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ManualsBrandsRFM ManualsComputer equipmentDN-2400E

molbox™ RFM™

(Ver 1.10 and Higher)

Reference Flow Monitor

Operation and Maintenance Manual

Summary of content (172 pages)

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molbox™ RFM™ (Ver 1.
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High pressure liquids and gases are potentially hazardous. Energy stored in these liquids and gases can be released unexpectedly and with extreme force. High pressure systems should be assembled and operated only by personnel who have been instructed in proper safety practices. © 1998 - 2007 DH Instruments, a Fluke Company All rights reserved. Information in this document is subject to change without notice.
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TABLE OF CONTENTS TABLE OF CONTENTS TABLE OF CONTENTS ............................................................... I TABLES .................................................................................. V FIGURES................................................................................ VI ABOUT THIS MANUAL ............................................................ VII 1. INTRODUCTION ................................................................. 1 1.1 PRODUCT OVERVIEW ..................
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3. OPERATION ..................................................................... 21 3.1 GENERAL OPERATING PRINCIPLES ...................................................................................................................................... 21 3.1.1 3.1.2 3.1.3 3.1.3.1 3.1.3.2 3.1.4 3.1.5 3.1.6 3.1.6.1 3.1.6.2 3.2 MAIN RUN SCREEN ....................................................................................................................
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TABLE OF CONTENTS 3.6 [SPECIAL] ................................................................................................................................................................................... 76 3.6.1 3.6.1.1 3.6.1.2 3.6.1.3 3.6.1.4 3.6.1.5 3.6.2 3.6.2.1 3.6.3 3.6.3.1 3.6.4 3.6.5 3.6.5.1 3.6.5.2 3.6.5.3 3.6.5.4 3.6.5.5 3.6.6 3.6.6.1 3.6.6.2 3.6.6.3 3.6.7 3.6.8 3.6.9 4. REMOTE OPERATION ....................................................... 95 4.1 4.2 OVERVIEW.......................
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 5.6 OVERHAUL ............................................................................................................................................................................... 144 5.6.1 5.6.1.1 5.6.1.2 5.6.1.3 5.6.1.4 5.6.1.5 5.6.1.6 5.6.1.7 5.6.1.8 5.6.1.9 6. TROUBLESHOOTING .......................................................149 6.1 7. OVERVIEW................................................................................................
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TABLES & FIGURES TABLES Table 1. molbloc-L Pressure Dependent Calibration Types ........................................................................ 5 Table 2. molbloc-L Ranges with Low Pressure Calibrations ....................................................................... 6 Table 3. molbloc-L Ranges with High Pressure Calibrations ...................................................................... 7 Table 4. molbloc-S Flow at Various molbloc Upstream Pressures ................................
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL FI G U R E S Figure 1. molbox RFM Front Panel............................................................................................................ 13 Figure 2. molbox RFM Rear Panel ............................................................................................................ 14 Figure 3. molbox RFM Internal Pneumatic Schematic – MICRORANGE OPTION RPT ACTIVE/INACTIVE ..........................................................................
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ABOUT THIS MANUAL ABOUT THIS MANUAL This manual provides the user with the information necessary to operate a molbox RFM, Reference Flow Monitor. It also includes a great deal of additional information provided to help you optimize molbox RFM use and take full advantage of its many features and functions. Before using the manual, take a moment to familiarize yourself with the Table of Contents structure: All first time molbox RFM users should read Section 2.
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1. INTRODUCTION 1. INTRODUCTION 1.1 PRODUCT OVERVIEW molbox RFM is a support unit for making low mass flow measurements using molbloc mass flow elements. molbox RFM reads calibration data off the molbloc EEPROM and measures molbloc upstream and downstream pressure using built-in high accuracy Reference Pressure Transducers (RPTs). An ohmic measurement system reads the resistance of the molbloc platinum resistance thermometers from which molbloc temperature is calculated.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1.2 SPECIFICATIONS 1.2.1 GENERAL SPECIFICATIONS Power Requirements Fuse Operating Temperature Range Storage Temperature Range Vibration Weight Dimensions Microprocessor Communication Ports Reference Pressure Transducers (RPTs) Ohmic Measurement System 85 to 264 VAC, 47 to 440 Hz, 18 VA max. consumption 1A/250V, slow blow, 5x20mm, NSN: 5920008930491 15 to 35 °C -20 to 70 °C Meets MIL-T-28800D 2.55 kg (5.6 lb) max. 8 cm H x 22.5 cm W x 20 cm D (3.1 in. x 8.
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1. INTRODUCTION 1.2.2.2 DIFFERENTIAL RPT (MICRORANGE OPTION) Piezoresistive silicon Type 0 to 12.5 kPa differential (0 to 1.8 psid) Range 0.14 Pa (0.00002 psi) Resolution ± 0.01 % FS Repeatability ± 0.05 % FS for one year. Taring sequence eliminates zero error. Accuracy 1.2.3 TEMPERATURE MEASUREMENT SPECIFICATIONS Specifications are for molbloc mounted Platinum Resistance Thermometers (PRT) combined with molbox RFM resistance measurement system and temperature calculation.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1.2.4.1.1 molbloc-L FLOW MEASUREMENT SPECIFICATIONS, MICRORANGE OPTION The microrange option (see Section 1.2.2.2) improves molbloc-L flow measurement specifications below 10 % FS of the molbloc range.
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1. INTRODUCTION The molbloc-L pressure dependent calibration types are summarized in Table 1. Table 1. molbloc-L Pressure Dependent Calibration Types CALIBRATION TYPE OPERATING PRESSURE NOMINAL DIFFERENTIAL PRESSURE AT MAX. FLOW 1E5 MOLBLOC ALL OTHER MOLBLOCS Full mod, low pressure 200 to 325 kPa absolute (29 to 48 psia) upstream of molbloc 5 kPa (.725 psi) 50 kPa (7.5 psi) Full mod, high pressure 325 to 525 kPa absolute (48 to 76 psia) upstream of molbloc Not available 50 kPa (7.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1.2.4.1.3 molbloc-L Ranges with Low Pressure Calibrations Table 2.
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1. INTRODUCTION 1.2.4.1.4 molbloc-L Ranges with High Pressure Calibrations Table 3.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1.2.4.1.5 molbloc-L DIMENSIONS molbloc-L SIZES [mm(in.)] 5E3 AND LOWER 1E4, 3E4 1E5 A 58.50 (2.303) 74.50 (2.933) 74.50 (2.933) B 16.00 (0.630) 24.00 (0.945) 24.00 (0.945) C 32.00 (1.260) SQ 48.00 (1.890) SQ 48.00 (1.890) SQ D 68.84 (2.750) 80.00 (3.150) 80.00 (3.150) E 19.06 (0.750) 28.00 (1.102) 28.00 (1.102) F 124.00 (4.881) 157.00 (6.181) 164.00 (6.458) G 1/4 in. VCR M 1/4 in. VCR M 1/2 in.
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1. INTRODUCTION 1.2.4.2 molbloc-S The flow range and operating pressure associated with molbloc-S operation depend on the molbloc used and its calibration options (see Section 1.2.4.2.2) Measurement Update Rate Range Resolution 1 second Depends on molbloc-S pressure dependent calibration type (see Section 1.2.4.2.2) 0.01 % of FS Linearity ± 0.25 % of reading Repeatability ± 0.10 % of reading 1 ± 0.30 % of reading 2 ± 0.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Table 4. molbloc-S Flow at Various molbloc Upstream Pressures FLOW [slm @ 0°C] WHEN molbloc-S UPSTREAM PRESSURE IS:[1][2] molbloc-S DESIGNATO R 20 kPa (3psia) 50 kPa (7 psia) 100 kPa (15 psia) KF [sccm/kPa] Minimum without vacuum[3 150 kPa (22 psia) 200 kPa (30 psia) 250 kPa (36 psia) 500 kPa (70 psia) ] 5E1-S 50 1 2.5 5 7.7 7.5 10 12.
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1. INTRODUCTION 1.2.4.2.2 molbloc-S PRESSURE DEPENDENT CALIBRATION TYPES See your molbloc’s Calibration Report to determine the calibration type of the molbloc you are using. Measurement uncertainty (accuracy) specifications for molblocs are valid only for gases with which the molbloc has been calibrated. All molbloc-S elements are calibrated in one standard gas, either air or N2, and may be calibrated in other gases. Calibrations with other gases are optional.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1.2.4.2.3 molbloc-S Dimensions molbloc-S SIZE [mm(in.)] 5E1-S A B C D E F G H I J K L 1E2-S 2E2-S 5E2-S 1E3-S 2E3-S 5E3-S 1E4-S 48.0 (1.89) SQ 48.0 (1.89)SQ 48.0 (1.89) SQ 48.0 (1.89) SQ 48.0 (1.89) SQ 48.0 (1.89) SQ 80.0 (3.15) SQ 24.0 (0.94) 24.0 (0.94) 24.0 (0.94) 24.0 (0.94) 24.0 (0.94) 24.0 (0.94) 40.0 (1.57) 40.0 (1.57) 48.0 (1.89) SQ 48.0 (1.89)SQ 48.0 (1.89) SQ 48.0 (1.89) SQ 48.0 (1.89) SQ 48.0 (1.89) SQ 80.0 (3.
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1. INTRODUCTION 1.2.5 FRONT AND REAR PANELS 1.2.5.1 FRONT PANEL The front panel assembly provides a 2 x 20 vacuum fluorescent display, a membrane keypad for local user interface and a SOFT ON/OFF key. 1. Display 2. Multi-function Keypad P 3. Remote Communication Indicator 4. SOFT ON/OFF Key and Indicator Figure 1.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1.2.5.2 REAR PANEL The rear panel assembly provides pressure and electrical connections to a molbloc mass flow element, communications interfaces and the power connection module. 1. Quick connectors to molbloc pressure connections (color coded) 2. Electrical power connector (IEC320-313) 3. IEEE-488 (GPIB) connector for host communications 4. COM1 (RS232) connector for host communications 5. Electrical connection to molbloc 6.
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2. INSTALLATION 2. INSTALLATION 2.1 UNPACKING AND INSPECTION 2.1.1 REMOVING FROM PACKAGING molbox RFM is delivered, along with its standard accessories, in a corrugated container with polyurethane inserts to hold it in place. Remove the molbox RFM and its accessories from the shipping container and remove each element from its protective plastic bag. 2.1.2 INSPECTING CONTENTS Check that all items are present and have NO visible damage. A molbox RFM includes: Table 7.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL If the molbloc/molbox system is being used to calibrate other devices (DUTs), the molbloc may need to be connected upstream or downstream of the DUT to operate within the pressure limits of the molbloc’s calibration type (see Sections 1.2.4.1.2, 2.2.4.2.2) and to accommodate the pressure requirements of the DUT. See the molbloc’s Calibration Report to determine the calibration type of the molbloc you are using.
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2. INSTALLATION For the electrical/data connection, use the molbox to molbloc electrical/data connection cable (P/N 102096). Connect the cable to the molbloc and then to molbox RFM rear panel connector labeled “molbloc”. Avoid making molbloc electrical connections to molblocs while molbox RFM is plugged in. Damage to the molbloc EEPROM may result (see Section 5.5.5) 2.3.4 GAS SUPPLY AND FLOWPATH CONNECTIONS Connect a gas supply to the molbloc.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Operating at pressures other than those of the molbloc-L pressure dependent calibration type (see Section 1.2.4.1.2) or molbloc-S calibration type (see Section 1.2.4.2.2) may result in out of tolerance flow measurements. Refer to the molbloc Calibration Report to determine its calibration type. 2.3.
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2. INSTALLATION If the molbox RFM fails to reach the main run screen: Service may be required. Record the sequence of operations and displays observed and contact a DHI Authorized Service Provider (see Section 7.2). molbox RFM is always powered and active when power is supplied through the rear panel power connector. The front panel ON/OFF key controls a SOFT ON/OFF only (see Section 3.1.4). 2.4.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 2.4.5 CHECK/SET SECURITY LEVEL molbox RFM has a security system based on user levels. By default, the security system is set to “low”, which includes certain access restrictions, and there is no password required to change the security level (see Sections 3.6.2). As part of the molbox RFM startup, set your desired security level and a password.
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3. OPERATION 3. OPERATION 3.1 GENERAL OPERATING PRINCIPLES 3.1.1 molbloc-L AND molbloc-S OPERATION molbox RFM operates somewhat differently depending on whether a molbloc-L or molbloc-S is connected to it. mobloc-L and molbloc-S operation use different displays and flow calculations and some menu items are present for only one type of molbloc. Most molbox RFM settings, such as gas, units, K factor, etc., are common to both molbloc-L and molbloc-S operation.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Depending on the placement of the molbloc-S in relation to the DUT and other hardware, and the availability and capacity of a vacuum pump that may be used, the molbloc-S downstream pressure will vary in different applications.
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3. OPERATION 3.1.4 SOFT [ON/OFF] KEY molbox RFM is equipped with a SOFT [ON/OFF] key and indicator LED on the bottom left hand corner of the front panel. The purpose of the SOFT ON/OFF key is to put molbox RFM into a dormant mode in which the display is turned OFF but power is still supplied and OVERPRESSURE functions are still active. When molbox RFM is ON, the ON/OFF indicator is ON continuously. When molbox RFM is SOFT OFF, the ON/OFF indicator blinks every 5 seconds.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL To determine if a molbox RFM is equipped with the microrange option, check the model number on the product label on the bottom of the molbox RFM case. If the model number includes a “-M”, the microrange option is installed. The microrange option is only active during molbloc-L operation. Mirorange has no effect on molbloc-S operation or measurement specifications. 3.1.6 REFERENCE PRESSURE TRANSDUCER (RPT) OVERPRESSURE 3.1.6.
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3. OPERATION 3.2 MAIN RUN SCREEN The molbox RFM MAIN run screen is its home display that is reached upon power up and from which other functions and menus are accessed. It is the top level of all menu structures. It indicates the current measured flow as well as a variety of additional information, if desired. The appearance of the MAIN run screen differs depending on whether the active molbloc is a molbloc-L or a molbloc-S. 3.2.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL molbox RFM has a SCREEN SAVER function that causes the display to dim if NO key is pressed for 10 minutes. Pressing a key restores full power to the display. The screen saver activation time can be changed or screen saving can be completely suppressed (see Section 3.6.5.1). 3.2.2 molbloc-S OPERATION As with molbloc-L there are limits on some of the conditions that may exist if the user expects to make accurate flow measurements with molbloc-S.
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3. OPERATION 3.3 MANUAL OPERATION molbox RFM is designed to offer the optimum balance between simple, intuitive operation and the availability of a wide variety of functions with a high level of operator discretion. The local operator interface is through the front panel’s 2 x 20 character alpha-numeric display and a 4 x 4 multi-function keypad. Remote operation by RS232 or IEEE-488 interface is also available (see Section 4). 3.3.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.3.2 SOUNDS molbox RFM is equipped with a variable frequency tone device to provide audible feedback and alarms. Sounds are used for the following indications: 3.3.3 Valid key press Brief beep. Choice between three frequencies or NO sound is available (see Section 3.6.5.2). Invalid key press Descending two tone “blurp”. Choice of NO sound is available (see Section 3.6.5.2). Totalizing time complete Three, 2 second beeps (see Section 3.4.6.4).
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3. OPERATION Table 8. Summary of molbox RFM Direct Function Key Operations DIRECT FUNCTION KEYS ARE ACTIVE FROM THE MAIN RUN SCREEN SEE CORRESPONDING MANUAL SECTIONS FOR FULL DETAIL Menu of commonly used setup features including unit changes and stability setting. Menu of less frequently used internal functions and settings including preferences, resets, molbox calibration, remote interfaces, BPR (back pressure ratio) when using molbloc-S. Turn automatic microrange ON/OFF.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL process gas is toxic or corrosive or simply because it is not available or convenient to use. When the process gas cannot be used for calibration, it is common to use a different gas for testing or calibrating (the calibration gas). In this case, a factor representing the relationship between the calibration gas and the process gas for the test device may be applied so that the calibration gas simulates the process gas.
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3. OPERATION When the K function is ON, as indicated by a following the current flow unit in the first line of the MAIN run screen, the current molbox RFM flow indication equals: (flow as calculated by molbox RFM for the selected gas) x (the current K factor) So the indicated flow is actually in error (biased) relative to the true flow through the molbloc by the value of the K factor.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.4.2.1 molbloc-L OPERATION The molbox RFM gases available for use with molbloc-L at the time of this manual printing are listed in Table 9. Table 9.
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3. OPERATION 3.4.2.2 molbloc-S OPERATION The molbox RFM gases available for use with molbloc-S at the time of this manual printing are listed in Table 10. Table 10. Available molbloc-S Gases GAS <1N2> Nitrogen <2Air> Air (dry and humid) In addition to dry air, molbox RFM supports measurement of ambient (humid) air flow with molbloc-S.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL The humid air correction applied to the molbloc measured flow is (from ASME FEDSM98-5309): qm(ratio) = a + bW + cW 2 + dW 3 where : a = 1.0000 b = −0.336872 c = 0.158514 d = 0.131924 If an incorrect value of W is entered (for example, using any non-zero W value while flowing dry air), an error will be introduced into the air flow measurement. W, humidity ratio, is different from relative humidity.
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3. OPERATION as well as units of volume flow (i.e., ccm). See Table 11 for a complete listing of the unit conversions available. molbox RFM can also display the measured flow in two different units of measure simultaneously (see Section 3.4.6.5). OPERATION The UNIT function is used to set the unit of measure of the molbox RFM flow display. To change the flow unit of measure press [UNIT]. 1sccm 2slm 3uccm The display is: 4pccm 5mg/s 6vlm Select the desired unit.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Volume flow is dependent on the actual temperature and pressure of the flowing gas at the point where volume flow is to be measured. Generally, this point is not at the molbloc, it is at another point in the flow system (e.g., at the device under test). At another point in the flow system, it is quite likely that the gas pressure and temperature are different from the gas pressure and temperature at the molbloc.
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3. OPERATION • User units (uxxx): The u prefix indicates user. This option is designed to provide support for volumetrically based mass flow units with a reference temperature other than 0 °C (see Section 3.4.3.3). Volumetrically based mass flow units preceded with the letter “u” (i.e., uccm, ulm) define standard conditions as pressure of 101.325 kPa (14.6959 psia) with the user specifying the reference temperature. User units take into account the true compressibility of the flowed gas.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL To measure flow in volume flow units (sometimes referred to as actual flow units), press [UNIT], under the UNIT function. If is not available, see Section 3.4.3.5. This selection accesses the menu of volume units available. Select the desired volume flow unit: 1. Current volume flow pressure. 2. Current volume flow temperature. Indicates if the current setting is to use the molbloc temperature. P101.325kPa Edit T21.
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3. OPERATION <#1> corresponds to the first of the six available selections under the UNIT function. Enter the number of the selection that you would like to change. The display becomes: Flow unit type: 1std 2user 3perfect 4vlm Select the flow unit type of the desired flow unit (see Table 11). Then select the desired unit. Table 11.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL • AUTOZ function: To periodically offset the molbox RFM RPTs relative to a reference pressure value in order to compensate for possible changes in the RPT zero between full recalibrations (see Section 3.4.4.4). • BPR function (present only in molbloc-S operation): To measure and display the molbloc-S back pressure ratio (BPR) while operating in a BPR mode, which does not continuously read and display BPR (see Section 3.4.4.5).
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3. OPERATION When the TARE function is activated, molbox RFM’s internal valves operate to pneumatically connect together the two absolute transducers, and both legs of the microrange option differential transducer if present, at the molbloc operating pressure. The user can select whether this pressure is the upstream or downstream molbloc pressure so that the tare can be made at the pressure that will be held stable during operation (generally by a regulator or because it is open to atmosphere).
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL The next display is: 1. The current pressure read by the upstream (left) and downstream (right) RPTs without taking into account the current tare value. These are untared readings in the current pressure units. 2. , flashing, to indicate that this is a TARE display showing the tare between the two absolute RPTs. 3. The difference between the untared upstream and downstream absolute pressure readings (upstream – downstream).
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3. OPERATION If the new tare is > 10 000 Pa, the new tare cannot be activated. Pressing [ENTER] or [ESCAPE] returns to the tare screen. It is likely that molbox RFM needs service or a grossly incorrect adjustment has been made to one or both of the RPTs. Microrange differential pressure RPT zero drift test (if microrange option present): When attempting to activate a new tare, molbox RFM checks the zero offset value of the microrange RPT. If the new tare is > 999 Pa, the new tare cannot be activated.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1. High Isolation: Open 2. Low Isolation: Closed 3. Bypass: Open 4. Mirorange Bypass: Open Figure 6. molbox RFM Internal Pneumatic Schematic – TARING molbloc-S OPERATION OPERATION To access the TARE function press [TARE], <1tare>. The display is: 1. The current pressure read by the upstream (left) and downstream (right) RPTs without taking into account the current tare value. These are untared readings in the current pressure units. 2.
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3. OPERATION the molbox RFM (see Section 3.4.2). When switching from the measurement of one gas to another, the old gas remaining in the circuit and the new gas being flowed may mix for some time so that the gas flowing through the molbloc is not purely the new gas. Erroneous measurements may result. For this reason, it is important to purge the lines upstream and downstream of the molbloc when changing gases.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL The purge time can be edited. Pressing [ENTER] causes molbox RFM to set its internal valving to the purge configuration (see Figure 14) and go to the PURGE display: 1. The current pressure read by the upstream (left) and downstream (right) RPTs in the current pressure unit of measure. 2. to indicate that this is a PURGE display. 3. Countdown seconds. of purge time remaining 202.347 kPaa 202.
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3. OPERATION 3.4.4.3.1 Leak Check molbox PURPOSE To check the internal molbox RFM pneumatic circuit for leaks. PRINCIPAL It is normally not necessary to run the MOLBOX LEAK CHECK procedure frequently. It is intended for troubleshooting purposes when there appears to be a leak or other molbox RFM measurement problem whose source cannot be identified by the SYSTEM LEAK CHECK or other troubleshooting means.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1. High Isolation: Closed 2. Low Isolation: Closed 3. Bypass: Closed 4. Mirorange Bypass: Closed if Active Open if Bypassed Figure 8. molbox RFM Internal Pneumatic Schematic – LEAK CHECK molbox Once the molbox RFM pressure connections are vented, press [ENTER]. 1. The pressure read by the upstream RPT (left), the downstream RPT (right) and the pressure unit of measure (middle). 2.
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3. OPERATION 3.4.4.3.2 Leak Check System PURPOSE To leak check the external system that is connected to the molbox RFM. PRINCIPAL It is recommended to run the SYSTEM LEAK CHECK whenever critical physical connections in the system attached to the molbloc are broken and reconnected. Critical connections are ones that are between the molbloc and the DUT, which, if they were to leak, would cause the flow through the molbloc and the DUT to differ.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1. Channel A High Isolation: Open 2. Channel A Low Isolation: Open 3. Bypass: Open 4. Microrange Bypass: Open Figure 9. molbox RFM Internal Pneumatic Schematic – SYSTEM LEAK CHECK – CHECKING OFFSET AND STABILITY molbloc-L operation Close an isolation valve downstream or plug the exhaust of the flow system that is being tested (downstream of the molbloc and the DUT if the molbloc/molbox is being used to test another device).
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3. OPERATION After 30 seconds, if the stability check is not passed, molbox RFM displays: • Leak is too large to If the pressure was not stable: continue • • If the molbloc temperature change was too great: Temp change was too If the offset between the RPTs was too great: Offset excessive great to find leaks check tare If any of the above three prompts occurs, check the external system for leaks and/or run the molbox RFM leak check before proceeding.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL To run the leak test, select <1run>. molbox RFM actuates internal valves to connect the upstream and downstream RPTs together, so they are both measuring an equal system pressure. (see Figure 10). 1. High Isolation: Open 2. Low Isolation: Open 3. Bypass: Open 4. Mirorange Bypass: Open Figure 10.
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3. OPERATION Next, close the isolation valve upstream of the molbloc so the gas supply is no longer open to the system being checked. Once the pressure has had time to stabilize, press [ENTER]. ENTER to start The next display is: 60 s leak check Press [ENTER] to begin the test The next display is: 1. The average pressure from the two molbox RFM absolute RPTs. 2. Current absolute pressure measurement in active pressure unit of measure. 3. SYSTEM LEAK CHECK count down in seconds. 199.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL The AutoZ function has no effect on the microrange (differential) RPT measurement (if present). PRINCIPAL AutoZ Purpose and Principle The main component of the change over time of the molbox RFM RPTs is change in zero or offset, independent of span. Offsetting or “rezeroing” molbox RFM RPTs relative to a reference between recalibrations allows measurement uncertainty specifications to be maintained with less frequent full calibrations.
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3. OPERATION RPTs is available. Though it may not be practical and generally is not necessary, the best possible reference with which to run AutoZ in absolute measurement mode is a gas operated piston gauge (such as a DHI PG7601) applying an absolute pressure near atmospheric pressure to the molbox RFM test port. The best day to day reference is a properly calibrated DHI RPM4 with a BA100K RPT interfaced directly as an external device to the molbox RFM COM2 port.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL To edit the current Poffset values, press [TARE], <4AutoZ>, <3edit>. The display is: 1. 2. Edit field for the value of Poffset of the upstream (1, Hi) RPT. Edit field for the value of Poffset of the upstream (1, Hi) RPT. Poffset:18.7 Pa UP1 Poffset:-3.5 Pa DN2 Edit the Poffset value(s) as desired and press [ENT] to activate the new value(s). Press [ESC] to abandon changes. The value of Poffset is always displayed and entered in Pascal (Pa). 3.4.4.4.
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3. OPERATION When the run AutoZ selection is made, if a HEAD correction is currently active (see Section 3.6.8) the head correction is momentarily disabled while running AutoZ to avoid “zeroing out” the head value. The value of Poffset is always displayed and entered in Pascal (Pa). Run AutoZ by Entry AutoZ by entry allows the value of Pstd,0 (see Section 3.4.4.4, PRINCIPLE) to be entered directly from the molbox RFM front panel.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL If molbox RFM is able to communicate with an RPMx on its COM2 port, the display is: 1. Real time reading (without head correction) of upstream (1, Hi) RPT in unit of measure on line 2. 2. Real time reading (without head correction) of downstream (2, Lo) RPT in unit of measure on line 2. 3. Real time reading of the RPMx connected to molbox RFM COM2 to provide the value of AutoZ Poffset. 96.772 kPaa 96.778 Pstd,0:96.
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3. OPERATION OPERATION Select [TARE], <5BPR>. The display is: 1. 2. The current pressure read by the upstream (left) and downstream (right) RPTs without taking into account the current tare value. These are untared readings in the current pressure unit of measure. 259.312 kPa ↓99.5769 BPR 0.38 The current BPR (ratio of downstream to upstream absolute pressure). Press [ENTER] or [ESCAPE] to exit the BPR function and return to the previous RUN screen and BPR mode. 3.4.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL OPERATION – molbloc-L Operation Press [P&T] from any run screen. The display is: 1. Pressure read by the upstream RPT (left), the downstream RPT (right) and the pressure unit of measure (middle). 2. The current differential pressure in the current pressure unit of measure. indicates the value is differential pressure. indicates the measurement is from the microrange differential RPT (if present). 3. 97.788 kPa mDP 0.005 97.783 Re 0.
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3. OPERATION 3.4.6 [DISPLAY] PURPOSE To select, from a variety of choices, the information that is displayed in the molbox RFM main run display. PRINCIPLE molbox RFM supports a variety of ADVANCED FLOW MEASUREMENT functions that are generally displayed on the second (bottom) line of the molbox RFM display. In summary, the available DISPLAY functions included are: RATE: Calculates and displays the current rate of change of flow in current flow units/second (see Section 3.4.6.1).
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL OPERATION To select a DISPLAY function, press [DISPLAY] from the MAIN run screen. 1avg 2rate 3hi/lo The display is: 4total 5unit 6dev ↓ 7freeze 8clean The cursor is on the active DISPLAY function. Selecting a DISPLAY function returns to the MAIN run screen with the selected function active. See Section 3.4.6, PRINCIPLE for a summary of DISPLAY functions and Sections 3.4.6.1 through 3.4.6.8 for detailed information on each DISPLAY function.
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3. OPERATION To go to a DISPLAY other than RATE, press [DISPLAY] and make a new DISPLAY choice. 3.4.6.2 <2AVG> (AVERAGE) PURPOSE To activate the AVERAGE DISPLAY and/or adjust the period of time over which averaging occurs. See Section 3.4.6, PRINCIPLE. OPERATION To access the AVERAGE DISPLAY, press [DISPLAY] and select <2avg>. The display is: Averaging Period: 1. Edit field for averaging period in seconds. Default is 20. Minimum 3, maximum 999. 20 s Edit the averaging time period if desired.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.4.6.3 <3 HI/LO> PURPOSE To activate the HI/LO DISPLAY. See Section 3.4.6, PRINCIPLE. OPERATION To activate the HI/LO DISPLAY press [DISPLAY] and select <3hi/lo>. Selecting <3hi/lo> resets the HI/LO values and returns to the MAIN run screen with the HI/LO DISPLAY active. With the HI/LO DISPLAY active, the MAIN run screen is: 1. Standard MAIN run screen top line. 2. Highest flow observed since HI/LO reset. 3.
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3. OPERATION 1. Standard MAIN run screen top line. 2. Total mass or volume accumulated over elapsed totalizing run time. 3. Units of measure of mass or volume (derived from the current flow unit) of the totalized value (see Table 12). The units of measure are not shown if the screen space is needed to show a large totalized value. 4. * 101.45 sccm Σ0.00 scc N20 00:00:00 Elapsed totalizing time (hh:mm:ss). Always starts from zero and counts up until totalizing period elapses.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.4.6.5 <5UNIT> PURPOSE To activate the UNIT DISPLAY. See Section 3.4.6, PRINCIPLE. OPERATION To activate the UNIT DISPLAY, press [DISPLAY] and select <5unit>. The unit of measure that will be used for the second line of the MAIN run screen display must then be selected. The unit selection process is identical to that of the [UNIT] function key (see Section 3.4.3).
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3. OPERATION OPERATION To activate the DEVIATION DISPLAY, press [DISPLAY] and select <6dev>. The display is: Target: 1. Edit field to edit the target value from which the deviations is to be measured. 100.00 sccm Edit the desired target value. Pressing [ENTER] returns to the MAIN run screen with DEVIATION DISPLAY active using the entered target value. With the DEVIATION DISPLAY active the MAIN run screen is: 1. Standard MAIN run screen top line. 2. Target value in current flow unit of measure. 3.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL With the FREEZE DISPLAY active, the MAIN run screen is: 1. Standard MAIN run screen top line. 2. Flow measured in the current flow units when [ENTER] was pressed (displays 0.00 by default when FREEZE DISPLAY is first activated). * 101.75 sccm N20 F 99.24 Pressing [ENTER] causes the current flow measured by molbox RFM to be captured and displayed.
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3. OPERATION PRINCIPLE Use of the microrange feature improves molbox RFM flow measurements while using molbloc-L only. Microrange has no effect and is disabled during molbloc-S operation. The molbox RFM microrange option (if present) improves molbox RFM flow measurements when using a molbloc-L element below 10 % FS of its measurement range.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.4.8 [MOLBLOC] PURPOSE To initialize and/or rapidly identify a molbloc that is connected to molbox RFM. PRINCIPLE molblocs carry an EEPROM on which are stored the molbloc identification header, molbloc specific flow calibration coefficients and the zero offset of the molbloc platinum resistance thermometers.
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3. OPERATION Table 13. molbloc-L Size and Nominal Range Designations molbloc “NOMINAL RANGE” DESIGNATION molbloc-L SIZE DESIGNATION 10 sccm 1E1 50 sccm 5E1 100 sccm 1E2 200 sccm 2E2 500 sccm 5E2 1 slm 1E3 5 slm 5E3 10 slm 1E4 30 slm 3E4 100 slm 1E5 molbloc-S elements are also identified by size designations, each of which relate to a specific molbloc-S KF value. molbloc-S flow ranges depend on calibration type and the pressure limitations of the application and molbox used.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL The default (and maximum) resolution setting is 0.01 % of the molbloc full scale. The RES setting does not affect the resolution of flow information transmitted remotely. Remote information is always sent using flow resolution of 0.001% of molbloc full scale (0.0001% when microrange is active). OPERATION To access the resolution function press [RES]. Press the [←] to decrease the resolution and [→] to increase the resolution.
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3. OPERATION 3.5.2 <2presU> PURPOSE To select/change the unit of measure in which molbox RFM displays pressure values. OPERATION To set the unit of measure in which molbox RFM displays pressure values, press [SETUP] and select <2presU>. Pressure unit type: The display is: 1SI 2other 3user Select the unit type desired, then select the unit desired. After the unit selection, operation returns to the previous run screen with the selected pressure unit of measure active.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.5.4 <4MOLBLOC> PURPOSE To initialize a molbloc when it is connected to molbox RFM and/or to identify the molbloc currently connected to molbox RFM. To determine the gases with which the molbloc has been calibrated. PRINCIPLE molbox uses molbloc specific calibration information contained in the molbloc's EEPROM to determine whether it should operate in molbloc-L or molbloc-S mode and in its calculation of flow through the molbloc.
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3. OPERATION OPERATION To adjust the stability limit press [SETUP] and select <5stab>. The display is: Flow stability test: 1. Entry field for setting the desired stability limit in the current flow unit of measure. Recalls the default stability limit or the last stability limit set. 0.5 sccm/s Edit the stability limit setting as desired. Pressing [ENTER] activates the new stability limit and returns to the current run screen.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL For example, to adjust a gas mix that is 95 % Nitrogen (N2) and 5 % Oxygen (O2): n Calculate the molecular weight of the mix. N2 molecular weight = 28.016 O2 molecular weight = 31.999 Mix molecular weight = (28.016 x 0.95) + (31.999 x 0.05) = 28.215 o Select N2, the highest concentration gas, as the molbox RFM gas. p Calculate: molecular weight of the mix molecular weight of the gas selecton on the molbox 28.215 28.016 = = 1.
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3. OPERATION <8head> Set the height for the pressure fluid head correction (see Section 3.6.8). <9BPR> Set the back pressure ratio (BPR) mode (for molbloc-S operation only) (see Section 3.6.9). OPERATION To access the SPECIAL menu, press [SPECIAL] from the MAIN run screen. 1reset 2level 3ul 4cal 5prefs 6remote ↓ The display is: 7log 8head 9BPR Select the desired function. See Sections 3.6.1 to 3.6.9 for detailed SPECIAL function descriptions. Some screens (e.g.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.6.1.1 <1SETS> PURPOSE/OPERATION To access Reset - Sets, press [SPECIAL] and select <1reset>, <1sets>. Reset - Sets clears and sets to default the user settings for various measurements. These include: • Flow unit of measure to sccm (see Section 3.4.3). • Pressure unit of measure to kPa (see Section 3.5.2). • Temperature unit of measure to °C (see Section 3.5.3). • Gas type to N2 (see Section 3.4.2). • Stability criterion to 0.
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3. OPERATION 3.6.1.3 <3COM> OPERATION/PURPOSE To access Reset - Com, press [SPECIAL] and select <1reset>, <3com>. Reset - Com clears and sets to default the molbox RFM communications ports (see Section 3.6.6). This includes: • COM1 and COM2 Baud rate: 2 400 Parity: Even Data bits: 7 Stop bits: 1 Terminating characters: , • IEEE-488 (GPIB) Address: 10 Terminating characters: , 3.6.1.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.6.2 <2level> PURPOSE To set user protection levels that restrict access to certain functions and to edit the password required for changing user levels. PRINCIPLE molbox RFM’s front panel user interface provides the means to access all molbox RFM user defined data, settings and functions including calibration data.
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3. OPERATION The High security level disables remote communications and returns an error message (“ERROR”) to all remote commands. All other security levels have NO effect on remote communications. The security levels are structured to support typical levels of operation. Specifically, the security levels prevent execution of the functions accessed by the key strokes marked by “•”. Table 16.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Table 17.
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3. OPERATION If there is an active password, the molbox RFM password entry screen appears. The user must enter the user defined password or the factory secondary password to proceed. When a password is entered correctly, operation proceeds to the <1change user level 2edit password> screen. RFM SN Password: nnn-xx pppppp The first field, , is the serial number of the molbox RFM, followed by a second field, , that counts the number of times that a secondary password has been used.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.6.3.1 UPPER LIMIT ALARM AND SEQUENCE When the pressure reaches the upper limit, molbox RFM continues normal operation but sounds an audible alarm. The alarm ceases if the pressure is decreased below the upper limit. When pressure reaches the overpressure limit, molbox RFM valves close, normal operation ceases and the display indicates: 670.250 kPa 651.
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3. OPERATION OPERATION To access the PREFS menu press [SPECIAL], and select <5prefs>. The display is: 1ScrSvr 2sound 3time 4ID See Sections 3.6.5.1 to 3.6.5.4 for detailed information on each PREFS function. 3.6.5.1 <1SCRSVR> PURPOSE To adjust the time setting of molbox RFM’s SCREEN SAVER function. PRINCIPLE molbox RFM has a SCREEN SAVER function which causes the display to dim after a front panel key is NOT pressed for a certain amount of time.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.6.5.3 <3TIME> PURPOSE To view and edit the molbox RFM internal time and date settings. OPERATION To access the TIME function press [SPECIAL] and select <5prefs>, <3time>. The display is: Edit: 1time 2 date 08:32:11 am 19980101 Select <1time> to edit the time. Edit hours, then minutes, then am/pm by pressing [ENTER] at each entry. Seconds go to zero when minutes are entered. Select <2date> to edit the date. YYYYMMDD format.
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3. OPERATION After the last of the twelve characters has been entered, the option is offered. Select <1no> to return to the ID edit screen. Select <2yes> to save the edited ID. The ID can also be set remotely from a computer which is quite a bit more convenient than entering characters from the keyboard (see Section 4.3.4). The ID cannot be cleared or reset by any RESET functions (see Section 3.6.1). 3.6.5.5 <5LOG> PURPOSE To view and/or clear the molbox RFM event log.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 3.6.6.1 COM1 AND COM2 The COMx ports can be set for the specific settings required by the user. The settings are baud rate, parity, data bits and stop bits. The available options are: Table 18. COM1 and COM2 Available Settings BAUD RATE 300, 600, 1 200, 2 400, 4 800, 9 600, 19 200 PARITY NONE, ODD or EVEN DATA BITS 7 or 8 STOP BITS 1 or 2 The default COMx settings are 2400, E, 7,1 for both COM ports.
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3. OPERATION The molbox RFM RS232 test can fail for three reasons: 1. The RS232 cable being used is incorrect (see Section 4.2.1.1 for information on the correct cable). 2. COM1 and COM2 do NOT have the same serial communications settings and therefore cannot communicate together (see Section 3.6.6.1 to set the COM ports). 3. COM1 or COM2 is defective. The reason for failed communications is almost always a cable or incorrect RS232 interface settings.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL OPERATION To access the MANUAL MICRORANGE function, press [SPECIAL] and select <7micro>. Manual microrange: The display is: 1off 2on If the manual microrange option is not installed, this menu will not appear. An
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3. OPERATION Use of the HEAD function to assure in tolerance measurements is most important when using molbloc-S at high pressures. Specifying the head height within ± 3 in. (7.5 cm) is adequate to assure that, even in the worst case, the uncertainty on the head correction will be insignificant relative to the tolerance of the measurement. OPERATION To access the HEAD function, press the [SPECIAL], <8head>. The display is: Edit head height: 1. Entry field for head height. 2.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 1. High Isolation: Open 2. Low Isolation: Open 3. Bypass: Closed 4. Microrange Bypass: Open Figure 11. molbox RFM Internal Pneumatic Schematic – molbloc-S OPERATION, BPR ON When the molbox RFM internal valves are positioned to allow both RPTs to measure the molbloc-S upstream pressure, the valve state is referred to as BPR OFF (see Figure 12). 1. High Isolation: Open 2. Low Isolation: Closed 3. Bypass: Open 4. Microrange Bypass: Open Figure 12.
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3. OPERATION For users who prefer to avoid automatic valving, there are two other BPR modes. BPR OFF mode keeps the molbox in the BPR OFF valve state at all times. BPR ON keeps the molbox in the BPR ON valve state at all times. BPR OFF mode should be used with caution, as it provides no monitoring of BPR to ensure that molbloc-S measurements are valid. When molbox RFM is used in BPR OFF mode, molbox cannot measure the molbloc-S downstream pressure and provides no monitoring or indication of the BPR.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL In Auto mode, when the valves are in BPR OFF state, flow is calculated from the average of the two RPT pressure readings as in BPR OFF mode. When the molbox RFM valves switch to the BPR ON valve state in Auto mode, the tare can no longer be dynamically calculated because the two RPTs are not measuring the same pressure.
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4. REMOTE OPERATION 4. REMOTE OPERATION 4.1 OVERVIEW Most of the molbox RFM’s front panel functions can also be executed by commands from a remote computer. The host computer can communicate with the molbox RFM using the molbox RFM COM1 RS232 port or the IEEE-488 port. The command syntax is the same for either port except when using the IEEE STD. 488.2 Common Commands. 4.2 INTERFACING Sending a command to the molbox RFM will place it into remote mode.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 4.2.1 RS232 INTERFACE To establish RS232 communications a standard “pin to pin” DB-9F to DB-9M RS232 cable must be used to connect the host COM port to molbox RFM COM1. The interface settings of both ports must be the same. molbox RFM supports an independent RS232 self-test to verify that the molbox RFM RS232 ports are operating correctly and the interface cable being used is valid.
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4. REMOTE OPERATION Table 20. COM2 DB-9M Pin Designation PIN # FUNCTION DESCRIPTION 2 RxD This pin accepts serial data from another molbox RFM or another device. 3 TxD This pin transmits serial data from the molbox RFM to another molbox RFM or another device. 4 DTR Data Terminal Ready. Held at +5 Volts. 5 Grn This pin is the common return for the TxD and RxD signals. IBM PC/XT DB-25F TO DB-9M CONNECTIONS 4.2.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 4.3.2 COMMAND SUMMARY Table 21. Command Summary SYNTAX PURPOSE *CLS Clears the status registers and all queues. *ESE(?) Read or set the Event Status Enable register. *ESR? Read the Event Status Register. *IDN? Identify the product and software version. *OPC(?) Read or set the Operation Complete register (not applicable to the RFM). *OPT? Read the molbox RFM options installed. *RST Reset user settings to factory defaults.
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4. REMOTE OPERATION Table 21. Command Summary (Continued) SYNTAX PURPOSE PR Read the next molbloc average pressure. PRDP Read the last measured microrange RPT pressure measurement (tare corrected). PRHI Read the last measured upstream pressure (tare corrected). PRLO Read the last measured downstream pressure (tare corrected). PURGE(=) Read the progress of or start the purge cycle. PUNIT(=) Read or set the pressure display unit. RANGE Read the range of the active molbloc.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Table 22.
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4. REMOTE OPERATION 4.3.4 COMMAND DESCRIPTIONS Each command description gives the full syntax showing usage. Ranges of parameters or parameter types are indicated. There are 2 types of commands. The Common and Status Commands support IEEE Std. 488.2, while the molbloc RFM commands access all other functions. 4.3.4.1 IEEE STD. 488.2 COMMON AND STATUS COMMANDS The molbox RFM supports a set of commands that are common to all instruments conforming to IEEE Std. 488.2 protocol.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL ∗ESR? Purpose Syntax Query Reply Remark Example Read the standard event register. “∗ESR?” n (0 to 255) The standard event register contents are cleared after reading. The reply is in decimal numeric form. Command: “*ESR?” Reply: 4” ∗IDN? Purpose Syntax Remarks Query Reply Example Identify the molbox RFM version, range, and serial number. “∗IDN?” The identification reply is made up of the manufacturer, the model, the serial number and the software version.
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4. REMOTE OPERATION ∗OPT? Purpose Syntax Remarks Query Reply Example Reads the list of installed molbloc RFM options. “∗OPT?” This query returns any registered option(s) installed in the molbox RFM. Each option is separated by a comma. A comma delimited text field of the installed options Command: Reply: Reply: “*OPT?” “NONE” (no options installed) “microrange” (microrange option installed) ∗RST Purpose Syntax Remarks Example Resets the molbox RFM settings to factory settings.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL ∗STB? Purpose Syntax Remarks Query Reply Example Read the status byte register. “∗STB?” The status byte register reflects the general status of the molbox RFM. The ‘MSS’ bit state is represented by bit 6. n (0 to 255) Command: Reply: “*STB?” “4” ∗TST? Purpose Syntax Remarks Query Reply Example 4.3.4.2 Read the power on self test status.
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4. REMOTE OPERATION ABORT Purpose To stop an active averaging, tare, purge or leak check cycle. Syntax Remarks “ABORT” This command should be used to ensure that molbox RFM is in a known state. The tare, purge, and leak check cycles put the RFM into a condition where it is not usable for normal flow measurement, so the “ABORT” command should be used before general operation of the unit begins if the previous state of the unit is not known.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL ALLR Purpose Syntax Remarks Read the next measurement of molbloc flow, the RFM upstream and downstream RPT pressure values, the molbloc temperature, and the optional microrange RPT pressure. “ALLR” The next available measurements are replied. This can take up to 1 second, since the molbox RFM waits for the next flow measurement before replying. The reply starts with the flow ready information. Then the flow value is given in the current flow units.
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4. REMOTE OPERATION BPR(=) Purpose Command: Query: Defaults Arguments Remarks Example Errors See Also Read or set the back pressure ratio (BPR) mode. This is only available when using a molbloc-S. “BPR =mode” “BPR=mode, suspend “BPR” “BPR=2,0” mode: ‘0’ BPR is kept “OFF” ‘1’ BPR is kept “ON” ‘2’ BPR is in “auto” mode. suspend: ‘0’ BPR normal operation ‘1’ BPR function is suspended, left in the current condition until set back to normal operation.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL DATE(=) Purpose Syntax Arguments Example Errors Read or set the internal clock date. “DATE” “DATE=yyyymmdd The year from 1980 to 2079. yyyy: The month from 1 to 12. mm: The day from 1 to the last valid day of the given dd: month. Command: “DATE=19981005” Reply: “19981005” ERR# 7: The time date is invalid. DEVICE=EXT Purpose Syntax Remarks Example Errors See Also To load the molbloc data into the molbox RFM.
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4. REMOTE OPERATION ERR Purpose Syntax Remarks Example See Also Read the last error message. “ERR” The “ERR” command provides more details about an error that has occurred. If the user receives an “ERR# nn” reply, the “ERR” command returns a brief description about the last error number that was replied. Command: “ERR” Reply: “Missing or improper command argument(s)” 4.3.3 FA= Purpose Syntax Arguments Remarks Example Errors See Also Start a single flow averaging cycle.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL FR Purpose Syntax Remarks Read the next measurement of flow through the molbloc as calculated by the molbox RFM. “FR” The next available flow value is read in the current flow units. This can take up to 1 second, since the molbox RFM waits for the next flow measurement before replying. The reply also contains ready information. Example The first 3 characters are reserved for the ReadyNot Ready status.
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4. REMOTE OPERATION FUNIT(=) Purpose Syntax Arguments Defaults Remarks Example Errors See Also Read or set the unit of measurement for the flow through the molbloc as calculated by the molbox RFM. “FUNIT=unit” “FUNIT” “FUNIT=sccm” unit: The flow unit used to display the measured flow. The flow unit displayed can be changed using this command. The flow unit must be supported by the molbox RFM. The flow unit protocol is the same as the front panel flow unit definitions.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL ID(=) Purpose Syntax Default Arguments Remarks Example See Also Read or set the user defined identification label. “ID=string” “ID” “ID=NONE” (no microrange option) string: An alphanumeric string up to 12 characters wide. The user defined ID label can be used to allow the user to “tag” the molbox RFM with a unique identifier. This ID is stored in non-volatile memory and cannot be erased by a power failure, system fault or reset.
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4. REMOTE OPERATION LEAKCK(=) Purpose Syntax Arguments Remarks Starts a molbox RFM or system leak check cycle or checks if a cycle is complete. “LEAKCK=type(,microrange)” “LEAKCK” type: “BOX” starts a leak check cycle on the molbox RFM internal circuit. The molbox must be prepared for the leak check by setting pressures and venting ports before the leak check is executed. “SYS” starts a leak check cycle on the system connected to the molbox RFM.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Errors See Also One of the arguments is not invalid. A leak check cycle has not been started. The microrange option is not installed in this RFM. A large leak exists. The temperature changed too much to test for a leak. The absolute RPT disagreement too great to test for a leak. Possible upstream leak. Possible downstream leak. Possible bypass leak. 3.2.4.
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4. REMOTE OPERATION Example Errors See Also “MICRORNG=AUTO” “AUTO” “MICRORNG” “OFF” (AUTO and MANUAL functions are disabled) “AUTO” (AUTO function is enabled) “ON” (MANUAL function is enabled) ERR# 7: The argument is invalid. ERR# 23: The microrange option is not installed in this molbox RFM. 3.1.2.6, 3.2.7, and 3.4.3 Command: Reply: Command: Reply: Reply: Reply: MOLBLOC Purpose Syntax Remarks Example Errors See Also Read the active molbloc header data.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL OHMS Purpose Syntax Remarks Example Errors See Also Read the resistance of the active molbloc’s PRTs in ohms. “OHMS” The most recent molbloc upstream and downstream PRT resistance measurement is returned in ohms. An error will be returned if there is a problem reading the molbloc PRTs. Command: “OHMS” Reply: “107.075 Ohms, 107.079 Ohms” ERR# 42: There is an error in the molbox RFM PRT measurement. 3.2.
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4. REMOTE OPERATION PCALDATE(=) Purpose Syntax Defaults Arguments Read or set the user RPT calibration dates.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL PRDP Purpose Syntax Remarks Example Errors See Also Read the last molbloc microrange transducer pressure. “PR” The last measured pressure from the optional microrange differential pressure transducer is read in the current pressure unit of measure. It is tare corrected. Depending on the molbloc pressure, the microrange transducer may be bypassed.
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4. REMOTE OPERATION PUNIT(=) Purpose Syntax Defaults Arguments Remarks Example Errors See Also Read or set the pressure display unit of measure. “PUNIT=unit” “PUNIT” unit: The text corresponding to the pressure unit of measure. The pressure unit protocol is the same as the protocol used for front panel entries and displays. This command determines what unit of measure is used to display pressure. Command: “PUNIT=MPA” Reply: “MPa” ERR# 7: The unit is invalid. 3.3.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL RATE Purpose Syntax Remarks Example See Also Read the next available rate of change of flow. ‘RATE” The next available rate change of flow in the current flow unit of measure per second is returned. Command: “RATE” Reply: “-0.01 sccm/s” 3.2.6.1, 3.1.2.4, and 3.3.5 RE Purpose Syntax Remarks Example See Also Read the value of Reynolds number representing the current flow through the molbloc as calculated by the molbox RFM.
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4. REMOTE OPERATION REMOTE Purpose Syntax Remarks Example See Also Enable remote local lockout operation. “REMOTE” A REMOTE command deactivates the front panel. All front panel controls will be disabled. The REMOTE command can only be canceled by a LOCAL command or by turning OFF the molbox RFM power then re-applying it. Command: “REMOTE” Reply: “REMOTE” “LOCAL” RES(=) Purpose Command Query Default Arguments Remarks Example Errors See Also Read or set the local flow display resolution.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL SR Purpose Syntax Remarks Example See Also Read the next available ready status. “SR” The current Ready/Not Ready status can be read directly using this command. If the reply is "NR" then the flow is Not Ready within the limits set by the stability settings. If the reply is "R" then the flow is Ready within the limits. The status is replied when the next flow measurement is finished.
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4. REMOTE OPERATION STDRES(=) Purpose Syntax Arguments Remarks Example Errors See Also Read or set the molbox’s two internal standard resistor values. “STDRES” “STDRES=R0100, R0110 R0100 : The 100 ohm standard resistor value (ohms). R0110 : The 110 ohm standard resistor value (ohms). The standard resistor values are used to periodically calibrate the PRT measurement system. These values are stored in the molbox’s factory data area, and should be modified with care.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL TARESETUP(=) Purpose Syntax Defaults Arguments Remarks Example Errors See Also © 1998-2007 DH Instruments, a Fluke Company To prepare the molbox RFM to be tared and to return the unit to normal operation after a tare has been completed. “TARESETUP=mode “TARESETUP” “TARESETUP=OFF” mode: “OFF” Allows normal operation of the molbox RFM. “UP” Connects both of the absolute RPTs to the upstream pressure.
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4. REMOTE OPERATION TARESET(=) Purpose Syntax Defaults Arguments Remarks Example Errors See Also To automatically tare the upstream and downstream RPT (and microrange RPT if present) or set the tare to a user defined value. “TARESET=tare(,microrange tare) “TARESET” “TARESET=0(,0)” tare: The tare value (-9999 to 9999 Pa). microrange The optional microrange transducer tare value (tare: 999 to 999 Pa).
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL TIME(=) Purpose Syntax Arguments Example Errors See Also Read or set the internal clock time. “TIME” “TIME=hh:mm:m hh:mmxs: The time to set in the format where hh is the hours from 1 to 12, mm is the minutes from 1 to 59 followed by “am” or “pm”. Command: “TIME=1:22am” Reply: “01:22am” ERR# 7: The time given is invalid. 3.4.5.3 TOTAL(=) Purpose Syntax Arguments Remarks Example Errors See Also Read the progress of or start a new totalize cycle.
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4. REMOTE OPERATION See Also 3.3.3, “TEMP” UDU(=) Purpose Syntax Arguments Defaults Example Errors See Also Read or set the user definable pressure unit. “UDU” “UDU=text, coef” text: The text to use to identify the unit. It can be up to 4 characters wide. This will be the text used to specify the unit if selecting it remotely, and that appears on the molbox RFM. coef: The coefficient to convert Pascal [Pa] to the user unit.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL VER Purpose Syntax Remarks Example Read the molbox RFM version. “VER” The software version of the molbox RFM can be read. This is useful for checking for the presence of the molbox RFM and for reference purposes. Command: “VER” Reply: “DH INSTRUMENTS, INC RFM Ver1.00” VLM(=) Purpose Syntax Defaults Arguments Remarks Example Errors See Also Read or set the volume flow unit of measure pressure temperature conditions. “VLM=pres(,temp)” “VLM” “VLM=101.
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4. REMOTE OPERATION 4.4 STATUS SYSTEM The status system includes the status reporting system which reports general molbox RFM events. The user can select which molbox RFM events will cause a status change event. These events are then reported to the status system (bit7 and bit3 of the status byte register), which also must be configured for the STATus subsystem to generate the service requests described in Section 4.4.1.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL status byte register (“∗STB?” or ”∗SRE n”) OPERation OPERation summary bit Bit7 (128) RQS/MSS Standard Event Status Register Bit6 (64) (“∗ESR?” or “∗ESE n”) ESB PON Bit5 (32) Bit7 URQ CMD EXE DDE QYE RQC OPC Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 MAV OUTPUT Bit4 (16) QUEUE N/A Bit3 (8) ERROR ERROR Bit2 (4) QUEUE N/A Bit1 (2) N/A Bit0 (1) Figure 13.
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4. REMOTE OPERATION • ERR: Error Queue not empty (Bit 2) • Indicates that at least one command error message is waiting in the molbox RFM IEEE-488 error message queue. Use the “SYSTem:ERRor?” query to get this message. 4.4.1.2 STANDARD EVENT REGISTER The molbox RFM contains an 8 bit Standard event register that reflects specific molbox RFM events that are not RPT dependent. Enabled events in this register will set or clear the ESB bit of the status byte register. Table 24.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION 5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION 5.1 PRODUCT OVERVIEW molbox RFM was designed for maintenance free operation. No maintenance is required other than: • Taring (zeroing) of Reference Pressure Transducers (RPTs). This function is not a separate MAINTENANCE function, it is part of regular operation (see Section 3.4.4.1).
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 5.2 CALIBRATION OF REFERENCE PRESSURE TRANSDUCERS (RPTS) 5.2.1 PRINCIPLE molbox RFM has two absolute Reference Pressure Transducers (RPTs): • One to measure molbloc upstream pressure • One to measure molbloc downstream pressure If molbox RFM is equipped with the microrange option (see Section 3.1.5), it also has a third low differential RPT.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION 5.2.1.1 PA AND PM COEFFICIENTS The coefficients used to adjust RPT readings are designated PA (a pressure adder or offset) and PM (a pressure multiplier or span set). The coefficients affect the RPT reading following: Corrected reading = (uncorrected reading • PM) + PA PA is expressed in pressure (always the SI unit, Pascal [Pa]). PM is dimensionless.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL DHI manufactures a variety of pressure standards suitable for calibration of molbox RFM RPTs. Contact DHI for additional information. 5.2.2.2 DIFFERENTIAL (MICRORANGE) RPT Gas operated pressure standard with the following characteristics: • Able to apply gauge pressure in 20 % increments between zero and 12.5 kPa (2 psi).
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION the low side is connected to the DOWN (LO) port (see Figure 15). Open the DOWN (LO) port to atmosphere by installing the accessory quick connector. If the calibration standard has a “low”, “minus” or “reference” port, consider connecting it to the molbox RFM DOWN (LO) port to assure that the calibration standard and molbox RFM are at the same ambient pressure.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 5.2.4.1 VIEWING RPT OUTPUTS OPERATION To view the molbox RFM RPT outputs press [SPECIAL] and select <4cal>, <1pressure>. Select RPT: 1upstrm The display is: 2dnstrm 3micro The <3micro> option is not present if the molbox RFM does not have the microrange option (see Section 3.1.5). Select the desired RPT and then select <1run>. Selecting <3micro> causes a warning message to appear concerning possible overpressure of the microrange RPT.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION 1. High Isolation: Open 2. Low Isolation: Closed 3. Bypass: Open 4. Mirorange Bypass: Open Figure 14. molbox RFM Internal Pneumatic Schematic – RUN UPSTREAM OR DOWNSTREAM ABSOLUTE RPT CALIBRATION 1. High Isolation: Open 2. Low Isolation: Open 3. Bypass: Closed 4. Mirorange Bypass: Closed Figure 15.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 5.2.4.2 VIEWING AND EDITING RPT PA, PM AND CALIBRATION DATE PURPOSE To view or edit PA and PM calibration coefficients (see Section 5.2.1.1) and the calibration date for each Reference Pressure Transducer (RPT). Capability to view and edit the values of the reference resistors used by molbox RFM’s ohmic measurement system (see Section 5.3) is also provided here. This capability is normally used only by a DHI Authorized Service Provider.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION The value of PA is always in Pascal [Pa]. The value of PM is dimensionless. 5.2.5 RPT CALIBRATION/ADJUSTMENT PROCEDURE WITHOUT USING CALTOOL FOR RPTS SOFTWARE Most users should use CalTool for RPTs software to assist in the calibration of molbox RFM reference pressure transducers. CalTool for RPTs and its documentation are provided on the General Accessories Disk delivered with molbox RFM.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL The value of PA must be entered in the pressure unit Pascal [Pa]. If your calibration data is in a unit other than Pascal, the calculated value of PA will be in the other unit and must be converted to Pascal before it is entered. If you are not familiar or comfortable with the mathematics for PA and PM manipulation, it is recommended you verify the as left readings as suggested in Step w above.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION Because the ohmic measurement system is set up to measure two PRTs, there are two reference resistors in the molbloc simulator. Their resistance is not identical so there are actually two reference temperatures printed on the molbloc simulator and an average temperature which correspond to the three temperatures on the molbox RFM [P&T] temperature display (see Section 3.4.5).
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL The DHI flash software loading utility and molbox RFM embedded software are available for download from the “SOFTWARE” section of DHI’s worldwide web site at www.dhinstruments.com. 5.5 RELOADING molbloc EEPROM FILE molbloc EEPROMs are programmed with: • A molbloc identifying header with range identifier, S/N and calibration date. • molbloc specific flow calibration coefficients for N2, and other gases if entered.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION 5.6.1 INTERNAL VIEW 1. 2. 3. 4. 5. 6. 7. 8. 9. Valving assembly Upstream (HI) absolute reference pressure transducer (RPT) Downstream (LO) absolute reference pressure transducer (RPT) Optional microrange differential reference pressure transducer (RPT), not present if microrange option not included (see Section 3.1.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 5.6.1.1 UPSTREAM ABSOLUTE RPT Measures absolute pressure on the UP (HI) molbloc pressure connection port. Connected pneumatically to the valving assembly and electrically to the main board (COM4) (see Section 5.6.1.8). 5.6.1.2 DOWNSTREAM ABSOLUTE RPT Measures absolute pressure on the DOWN (LO) molbloc pressure connection port. Connected pneumatically to the valving assembly and electrically to the main board (COM5) (see Section 5.6.1.8) 5.6.1.
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5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION 1. High Isolation: Normally Closed 2. Low Isolation: Normally Closed 3. Bypass: Normally Closed 4. Mirorange Bypass: Normally Open Figure 17. molbox RFM Valving Assembly Schematic 5.6.1.8 MAIN BOARD The main board is controlled by the micro board (see Section 5.6.1.6). The main board supports the 12 V drivers for the valving assembly solenoid excitation, the ohmic measurement system and the beeper.
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6. TROUBLESHOOTING 6. TROUBLESHOOTING 6.1 OVERVIEW molbox RFM is a sophisticated flow measuring instrument with advanced on-board features and functions. Before assuming that unexpected behavior is caused by a system defect or breakdown, the operator should use this manual and other training facilities to become thoroughly familiar with molbox RFM operation.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Table 25. Troubleshooting Checklist (Continued) SYMPTOM PROBABLE CAUSE SOLUTION Displays <******> where a numerical value should go. Number to be displayed is too large for allocated space. Usually due to an erroneous setting or measurement causing an out of limit value to be calculated. Check settings that may be causing an out of limit measurement and adjust if necessary. (3.4.5, 3.4.1, 3.5.
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6. TROUBLESHOOTING Table 25. Troubleshooting Checklist (Continued) PROBABLE CAUSE SOLUTION Flow indication appears to be incorrect. SYMPTOM Reference pressure transducer(s) (RPT) are inoperable or out of calibration. Use [P&T] to view pressure indications. Recalibrate RPTs if necessary. (3.4.5 and 5.2) Flow indication appears to be incorrect. The gas selected is not the gas flowing through the molbloc. Select the correct gas. (3.4.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Table 25. Troubleshooting Checklist (Continued) SYMPTOM PROBABLE CAUSE SOLUTION UNABLE TO MAKE MOLBLOC-S FLOW MEASUREMENTS OVER FULL EXPECTED FLOW RANGE. molbloc-S back pressure too high The downstream pressure on molbloc-S must always be significantly lower than the upstream pressure to maintain critical flow. When upstream pressure is reduced, the back pressure ratio may become too high to make valid flow measurements. (3.1.
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6. TROUBLESHOOTING Table 25. Troubleshooting Checklist (Continued) SYMPTOM PROBABLE CAUSE SOLUTION Flow rate is changing but display of flow is not and the bottom right hand corner of the display is a numerical countdown followed by . AVERAGE DISPLAY function is ON and pressure display is updating only with the average value at the end of each averaging cycle. Go to a DISPLAY function other than AVERAGE or press [+/-] to get the instantaneous value AVERAGE DISPLAY. (3.4.6.
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7. APPENDIX 7. APPENDIX 7.1 CONVERSION OF NUMERICAL VALUES molbox RFM performs all internal calculations in SI units. Numerical values input or output in other units are converted to SI immediately after entry and back to other units just before output as needed. The tables below provide the conversion coefficients used by molbox RFM to convert numerical values expressed in SI units to corresponding values expressed in other units. 7.1.1 PRESSURE Table 26.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL 7.1.3 FLOW Table 28. Conversions From kg/s To sccm At 0 °C For Various Gases TO CONVERT FROM KG/S TO SCCM AT 0 °C MULTIPLY BY Air (Air) 4.64109 E+07 Argon (Ar) 3.36398 E+07 Butane (C4H10) 2.22112 E+07 Carbon Dioxide (CO2) 3.03490 E+07 Carbon Monoxide (CO) 4.79862 E+07 Carbon Tetrafluoride (CF4) 1.52386 E+07 Ethane (C2H6) 4.42602 E+07 Ethylene (C2H4) 4.75813 E+07 Fluoroform (CHF3) 1.90128 E+07 Helium (He) 3.
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7. APPENDIX Table 30. Conversions From Volumetrically Based Flow Units At 0 °C To Corresponding Units At Another Temperature (uxxx) TO CONVERT VOLUMETRICALLY BASED UNITS AT 0 °C TO CORRESPONDING UNITS AT ANOTHER TEMPERATURE, Θ, (UXXX) sccm MULTIPLY BY (TN + θ )⋅ Ζ (P ,(T slm N slh N +θ )) TN ⋅ Ζ N scfm scfh sm3m sm3h Where: θ= Alternate reference flow temperature [°C]. TN = 27315 . K PN = 101325 Pa Z ( PN ,(TN +θ )) ;Z N gas dependent compressibility factors Table 31.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Table 32. Conversion From mole/s To pccm TO CONVERT MOLE/SEC TO PCCM MULTIPLY BY ANY GAS 1.34483 E+06 The “p” in pccm indicates “perfect” in which a gas compressibility factor of 1 is assumed for all gases. In early 1996, SEMI, a semiconductor industry group, adopted standard E12-96 which specified that this definition be used for volumetrically base mass flow units. Table 33.
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7. APPENDIX 7.2 WARRANTY STATEMENT Except to the extent limited or otherwise provided herein, DH Instruments, a Fluke Company (DHI) warrants for one year from purchase, each new product sold by it or one of its authorized distributors, only against defects in workmanship and/or materials under normal service and use. Products which have been changed or altered in any manner from their original design, or which are improperly or defectively installed, serviced or used are not covered by this warranty.
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8. GLOSSARY 8. GLOSSARY Absolute As in “absolute pressure”. Pressure expressed relative to vacuum. BPR Back Pressure Ratio. The ratio of the downstream pressure to the upstream pressure on a molbloc-S critical flow based molbloc element. The BPR is used to determine whether Critical Flow conditions exist so that molbloc-S flow measurements are valid. Critical flow Also known as “sonic flow”.
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molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL Rate A DISPLAY function in which the current rate of change of the flow in flow units/second is displayed. A measure of stability of the flow. See also Stability Limit. Ready/Not Ready Indication of when flow is stable within the stability limit and below the flow Reynolds number limit. See also Stability Limit. Reynolds Number A ratio of the inertia forces to the viscous forces in a flowing fluid.