Operator's Manual Model 370 Digital Pressure Gauge
Table of Contents INTRODUCTION About this Manual ....................................................................................... iii SECTION ONE Installing the Model 370 .............................................................................. 1 SECTION TWO: SUMMARY OF FUNCTIONS 2.1 Keyboard Functions ............................................................................ 3 2.2 Display Symbol .................................................................................... 4 2.
Appendices Appendix I.1 I.2 I.3 I.4 I.5 I.6 I: SETUP FUNCTIONS Formatting Baud Rate ....................................................................... 23 Disabling Beeper ............................................................................... 24 Programmable Stability Indicator ...................................................... 24 Omitting Engineering Units ................................................................ 25 Software Revision Number ........................................
Introduction Congratulations, and thank you for purchasing a SETRA Model 370 high accuracy Digital PressureGauge. Its ease of operation and durable construction will provide years of reliable service. While thegauge is easy to operate, it is advisable to read this guide carefully before use. It is designed to help you take full advantage of the functions and performance of the gauge. This guide is divided into five major sections: Section One explains installation and power requirements for the Model 370.
OUTLINE DRAWING Side View 5.5 140 6.0 152 8.55 217 7.2 183 Rear View 7.5 191 o o AC Power 8.
Section One INSTALLING THE MODEL 370 The Setra Digital PressureGauge, Model 370, is a highly accurate pressure measurement system utilizing the patented SETRACERAM sensor, advanced microcomputer based electronics, and sophisticated firmware, resulting in a 0.02% FS system accuracy.
Portability and Accuracy Right Where You Need It Display min/max 6 digit LCD with Annunciators for Alarms, Min/Max values and Engineering Units. Tracks Minimum and Maximum Values Encountered. f(p) Programmable NonLinear Function Key for Barometric Ranges. Converts True Barometric Pressure To Sea Level Pressure. Digital Pressure Gage O.K. User Programmable Indication of Pressure Signal Stability. SEA LEVEL HI LO ALARM units ft mmbar in hg H2O PSI -888888 O.K.
Section Two SUMMARY OF FUNCTIONS 2.1 KEYBOARD FUNCTIONS print Send information to a printer or other peripheral. conv Convert engineering units being displayed. set points Display HI and Lo Alarm setpoints. zero Enter relative or absolute tare value. min max Display minimum and maximum value encountered. clear Clear the number or key sequence being entered or displayed. f(p) Convert true pressure to SEA-LEVEL pressure (absolute pressure).
2.2 DISPLAY SYMBOLS OK The readings are within the user defined stability requirement. hPa The reading shown is given in hectopascals. PSI The reading shown is given in pounds per square inch. inHg The reading shown is given in inches of mercury. mbar The reading shown is given in millibars. mmHg The reading shown is given in millimeters of mercury. inH2O The reading shown is given in inches of water. mmH2O The reading shown is given in millimeters of water.
2.3 DISPLAY MESSAGES UnAbLE The gauge is unable to execute the requested function in its current configuration. Clear the display and continue. OFLO The display is over-ranged because excess pressure is applied or because the user-defined conversion exceeds the number of digits available in the display. FLASHING DISPLAY The pressure applied exceeds the rated range of the sensor. BUSY The gauge is acquiring a stable reading.
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Section Three DIGITAL PRESSURE GAUGE FUNCTIONS 3.1 ENTERING A NUMBER OR FUNCTION To enter a number or function, simply press the key or keys which correspond to the numbers or functions you wish to enter. 3.2 CLEARING A NUMBER OR FUNCTION To clear a function or number you have begun to enter, press the CLEAR key. This automatically returns the gauge to display mode, without affecting any other functions which may be in use. To reset the Model 370 to its power up condition, press "-", then CLEAR.
3.4 CONVERTING ENGINEERING UNITS The Model 370 will measure pressure in any engineering units, including six built-in pressure conversions, two built-in altitude conversions, and a user definable conversion. To convert from one unit to another, simply press the CONV key repeatedly until the units you want are in the display. The order of units is as follows: hPa - PSI - mbar - mmHg - inHg - mmH2O - inH2O - ft - m - units. To return directly to the units the gauge was calibrated in, press "-" then CONV.
3.6 SETTING AND USING ALARM SETPOINTS The Model 370 has an alarm capability which will indicate when the pressure applied has exceeded a high or a low setpoint. The annunciators are an audible tone, a display message of "HI ALARM", and a message sent through the communications port. To examine the current value of the setpoints, press SETPOINTS.
3.7 USING THE TARE AND ZERO FUNCTION The TARE function on the Model 370 gives you a way of setting the displayed reading to zero or of subtracting a specified offset so that you can monitor changes in pressure relative to a known starting point. This is done by creating a tare value which will be subtracted before each updated reading is displayed. To set the display to zero, press ZERO.
3.8 PRINTING INFORMATION Your Setra Digital Pressure Gauge is designed to print information when connected to a printer, using the following procedure: 1. Set the printer up as described in its' manual. 2. Connect the RS-232 cable from the printer to the Model 370. 3. Make sure the printers on-line light is on. 4. Press PRINT to send the reading in the Model 370 display to the printer. NOTE: When using a printer set the baud rate of the gauge to match that of the printer (see Appendix I).
3.9 REPETITIVE PRINTING It is sometimes desirable to record pressure measurements at fixed intervals of time. To print at fixed intervals, follow this procedure: 1. Connect a printer as outlined in Section 3.8. 2. Enter the number of seconds between readings. 3. Press PRINT. The gauge will print out a reading at the specified interval. 4. To cancel repetitive printing, press "-" then PRINT. To interpret the meaning of the symbols printed, see Appendix III - "RS-232C Serial Data Communications.
3.10 PRINTING SYSTEM STATUS To get a summary of the condition of all active functions, press SETUP, then press PRINT. A sequence of information will be printed indicating the range of the gauge and the status of any functions which are currently in use, as shown in this example. STATUS ELEV: MAX: MIN: HI ALARM: LO ALARM: ZERO: UNIT: 256 FT 14.4193 PSI 14.5188 PSI 15.8000 PSI 11.0000 PSI 1.0000 PSI 689.47 PSI The actual messages will vary depending on which functions are in use. 3.
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Section Four ADVANCED PRESSURE GAUGE FUNCTIONS 4.1 USER DEFINED ENGINEERING UNITS The Setra Digital Pressure Gauge has several built-in engineering units conversions which are accessed simply by pressing CONV. If you want to display pressure in units other than those provided, use the following procedure. Units can be directly changed by entering a factor (number to multiply by) or a divisor (number to divide by) and will be indicated in the display by "units". 1. Calculate the ratio you wish to enter.
2. the conversion ratio; 3. the command U, for CONVERT UNITS; 4. any combination of 5 alphanumeric characters, including spaces, to identify the engineering units. For example, if the transducer is currently reporting in PSI and the desired units are grams per square centimeter the ratio is 70.307g/cm2 per psi (a multiplier. Transmit: 70307Ug/cm2 the 370 will now report in g/cm2 to an interrogation.
4.2 DIGITAL ALTIMETER SETTING INDICATOR The Model 370 may be used to display corrected sea-level pressure by "reducing" true barometric pressure at a known elevation to what the pressure would be at sea-level at the same latitude and longitude. This function is only available on gauges with barometric or absolute pressure sensors. Before using the "SEA LEVEL" correction mode, you must first determine and enter the station elevation, which is the altitude above sea level at which the gauge is installed. 1.
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Section Five DISPLAYING ALTITUDE The Model 370 Digital Pressure Gauge can be used to display a variety of altitude measurements. It may be used as an altimeter calibrator, a standard altimeter, a true corrected altimeter (self corrected or remote), or as a relative altimeter. It may be used to indicate small relative changes in altitude through the use of the zero/tare function. This function is only available on gauges having absolute or barometric pressure sensors. 5.
5.2 DISPLAYING TRUE ALTITUDE The Model 370 can function as an altimeter displaying true altitude by correcting the above Standard Atmosphere conversion for the local barometric pressure. This correction can be setup two ways. If you are starting at a known station elevation, use the following procedure: 1. Press CONV until the gage is displaying pressure units (make sure not to select "ft" or "meters"). 2. Press SETUP, then press the f(p) key. The display will read "CAL FP". 3.
If you are not at a known elevation, the gauge may be used in true altimeter mode by obtaining an Altimeter Setting Indication (sea level corrected pressure) from a local airport or weather station, and following this procedure: 1. Press the CONV key until the engineering units of the known sea level pressure appears in the display. 2. Enter the known sea level pressure and press ZERO. The difference between the sea level pressure and the current pressure is displayed. 3.
5.3 MEASURING RELATIVE ALTITUDE To measure relative altitude in either Standard or True Altimeter Mode, a reference altitude may be established by setting the displayed reading to zero, or by offsetting it by a specified amount entered as a tare value. 1. Use one of the above procedures to display either Standard or True Altitude. 2. To set the displayed reading to zero, press ZERO. 3. To subtract an offset from the display, enter the amount of the offset and press ZERO. 4.
Appendix I SETUP FUNCTIONS I.1 FORMATTING BAUD RATE The Setra Digital Pressure Gauge is capable of interfacing with a wide variety of computers or other devices through the RS-232 serial communications port. Devices which are connected this way must be set up to communicate at the same rate of speed. To change the baud rate of the gauge (the rate at which the gauge sends information out through the port) so it agrees with that of the device connected to it, use the following procedure. 1.
I.2 DISABLING THE BEEPER The gauge emits a tone to verify the entry of a number or function. To disable the tone for silent operation, use the following procedure: 1. Press CONV until the gauge is displaying pressure units (make sure it is not displaying in "ft" or "meters"). 2. Press the "-" key. 3. Enter "9999". This is the beeper access code. 4. Press SETUP. The beeper is disabled. To reactivate the beeper, repeat Steps 2-4. I.
I.4 OMITTING ENGINEERING UNITS Some applications may require frequent switching from one engineering unit to another. The Model 370 can be setup to omit one or more of the built-in engineering units to reduce the number of times CONV must be pressed to get from one unit of measure to the next. 1. Press CONV until the gauge is displaying pressure units (make sure it is not displaying in "ft" or "meters"). 2. Press the "-" key. 3. Enter "2222". This is the Engineering Units access code. 4. Press SETUP.
I.6 SELF DIAGNOSTICS The Model 370 has a built-in self diagnostic procedure. This procedure prompts an operator to verify that the gauge is fully operational, (but does not verify proper calibration), by checking the keyboard, the keyboard decoder, the display, and a checksum test on internal memory. 1. Press CONV until the gauge is displaying pressure units (make sure it is not displaying in "ft" or "meters"). 2. Press the "-" key. 3. Enter "8888". This is the Diagnostic access code. 4. Press SETUP.
Appendix II CALIBRATION The zero and span of the Model 370 Digital Pressure Gauge may be calibrated using the following procedures. A high accuracy primary pressure standard is recommended as the calibration source, since the high accuracy of the Model 370 will be adversely affected if the calibration pressure is not of equal or greater accuracy. The calibration procedure will require the same pressures, in the same engineering units (usually PSI), as were originally calibrated at the factory.
lI.2 SPAN CALIBRATION To perform the span calibration on the Model 370, it is necessary to apply both the zero and the full scale pressures, as in the following procedure: 1. Make certain the gauge is in a stable temperature environment for several hours before calibration. 2. Press SETUP, then press SPAN. The display will read "APPLY" and the pressure required for zero calibration. 3. Apply the indicated pressure from a high accuracy standard. 4. Press SETUP.
Appendix III RS-232 SERIAL DATA COMMUNICATIONS The Setra Model 370 Digital Pressure Gauge is equipped with a bidirectional RS-232 interface which allows communications between the gauge and other devices which are also equipped with an RS-232 interface. This section provides detailed technical information showing how to operate the Model 370 remotely from a computer. To perform printing operations to a serial printer, Section 3.7 "Printing Information" and Appendix I.
III.2 SENDING COMMANDS TO THE GAUGE All the functions of the Model 370 may be executed by sending the appropriate command from the computer to the gauge. The commands are standard alphabetic characters which correspond to keys on the front keypad of the gauge. The table below also lists the ASCII and hexadecimal values of the codes for those interested in more technical programming. FUNCTION CODE Setup Clear Conv Min/Max F(p) Setpoints Zero Span Print S C U M B A Z F P . Verify .
III.3 RECEIVING DATA FROM THE GAUGE There are several types of messages which the gauge may send in response to the various commands. The immediate response to the PRINT command interrogation is the most common message. It is a string of characters consisting of the reading on the display and other information. The format of that string of characters is shown below: + 1 2 3 .
III.4 IMMEDIATE AND REPETITIVE PRINT MODES Two print modes are available on the Model 370, as discussed in Sections 3.8 and 3.9. The immediate print interrogation, used in the example above, is the preferred method of getting pressure data to a computer program. The repetitive print mode is intended for sending data to a printer or data logger at a time interval which is user definable (Section 3.9). III.
III.7 RS-232 INTERFACE HARDWARE The RS-232 Communication Standard describes in detail the requirements and conventions of RS-232. For most applications, the information given here is sufficient to solve any problems. The Setra Digital Pressure Gauge implements the majority of the RS-232 communications standards, but does not provide handshaking lines (such as busy, DSR, or DTR).
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Appendix IV ACCESSORIES AND OPTIONS IV.1 BATTERY / RECHARGER OPTION The Model 370 Digital Pressure Gauge can be operated as a portable instrument with the battery/recharger option. The battery option is designed to allow a standard 8 hour workshift, followed by a 16 hour recharge cycle. The battery option is a rechargeable 12 VDC Nicad battery, and an automatic internal battery charger which functions whenever the gauge is plugged into an AC outlet.
IV.2 IN CASE OF DIFFICULTY If a problem persists which cannot be solved by reading the appropriate sections of this manual, contact a SETRA Applications Engineer for assistance at the toll free number: 1-800-257-3872 IV.3 OPTIONS 1. Internal rechargeable battery pack. 2. 19 inch rack mount kit.
Pressure Ranges Model 370 Specifications Type of Pressure Barometric Pressure Range Display 600 to 1100 mbar 600.00 to 1100.00 800 to 1100 mbar 800.00 to 1100.00 Absolute 0 to 10 psia 10.0000 0 to 20 psia 20.0000 0 to 50 psia 50.0000 0 to 100 psia 100.000 Proof Pressure: 150% of full scale pressure range. Altitude Range1 -1000 to 13,800 ft. -1000 to 6,400 ft. 10,300 to 100,000 ft. -1000 to 100,000 ft. -1000 to 100,000 ft. -1000 to 100.000 ft.
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Appendix V WARRANTY INFORMATION V.
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Published by: Setra Systems, Inc. 159 Swanson Road, Boxborough, MA 01719 Telephone (800) 257-3872 or (978) 263-1400 Telefax (978) 264-0292 Web: www.setra.
