EXCELLENCE IN MAGNETICS AND CRYOGENICS AMI MODEL 188CPS POINT-SENSING INSTRUMENT INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS American Magnetics, Inc. PO Box 2509, 112 Flint Road, Oak Ridge, TN 37831-2509, Tel: 865 482-1056, Fax: 865 482-5472 Rev.
Introduction The American Magnetics, Inc. (AMI) Model 188CPS Point Sensing Instrument system is a microprocessor-based solution designed to provide sensing for up to five (5) points for virtually any non-conducting liquid. Capacitance-based point sensing The system consists of a Model 188CPS Point Sensing Instrument, plate sensors, and connecting cables. The instrument sensing elements are typically parallel plate capacitors which are mounted on a stainless steel support tube.
Introduction 2
Introduction Front Panel Layout AMI &$/,%5$7,21 0RGHO &36 3RLQW 6HQVLQJ ,QVWUXPHQW 6(1625 6(1625 6(1625 6(1625 0$; 0,1 6(1625 1 2 1 Power switch and indicator LED 2 LED indicators 3 Recessed calibration push-buttons 3 3
Introduction Rear Panel Layout AMERICAN MAGNETICS, INC. OAK RIDGE, TN U.S.A. 115/230 VAC 50/60 Hz SELECTOR SW.
Introduction System Diagram REAR PANEL AMERICAN MAGNETICS, INC. OAK RIDGE, TN U.S.A. 115/230 VAC 50/60 Hz SELECTOR SW. INSIDE RELAY CONTACTS OSC1 OSC2 OSC3 OSC4 OSC5 1 2 3 4 5 EXTENSION CABLES RG-59/U COAXIAL CABLE, 6 FT. LENGTH STANDARD (VARIABLE) OSCILLATORS OSCILLATOR CABLES RG-59/U COAXIAL CABLE, 6 FT.
Introduction System Diagram 6
Introduction Specifications Instrument Specifications Input line voltage 115/230 or 100/200 VAC ±10% Input line frequency 50-60 Hertz, 1 phase Measurement accuracy ± 0.25 inches Dimensions 3.8" H x 8.4" W x 11.1" D, Standard 3.475" H x 19" W x 11.1" D, Rack Mount Weight 4.0 lbs. Standard; 4.9 lbs. Rack Mount Operating environment 15 - 50°C non-condensing Relay Contact Specifications Max switching VA 10 Max switching voltage 200 VDC Max switching current 0.5 A Max continuous current 1.
Introduction Manual Legend Instruction manual symbol: the product is marked with this symbol when it is necessary for you to refer to the instruction manual in order to protect against damage to the product or personal injury. Hazardous voltage symbol. Warning The Warning sign denotes a hazard. It calls attention to a procedure or practice, which if not correctly adhered to, could result in personal injury. Do not proceed beyond a Warning sign until the indicated conditions are fully understood and met.
Table of Contents 1 Installation ..........................................................................................11 2 Calibration..........................................................................................15 Principle of operation..................................................................................... 15 Calibration procedure .................................................................................... 15 Variations in the dielectric with changing density......
Table of Contents 10
1 Installation Warning Before energizing the instrument, the earth ground of the power receptacle must be verified to be at earth potential and able to carry the rated current of the power circuit. Using extension cords should be avoided, however, if one must be used, ensure the ground conductor is intact and capable of carrying the rated current.
Installation Installing the sensor 2. Rack mount the instrument if desired If the instrument has a rack mount chassis, follow the following procedure: a. Attach the rack mount adapter pieces to the instrument by first removing the four screws on the side of the instrument that attach the cover to the chassis. Attach the rack mount adapter pieces to the sides of the instrument by reinstalling the screws. b.
Installation Interconnect with oscillators Caution Moisture or contaminants in any of the BNC coaxial connectors can short out the sensor and cause a false ‘full’ level indication or other erroneous readings. A pack of non-conductive electrical connection lubricant (ECL) has been included with the liquid level sensor packaging to reduce the possibility of this occurring. If desired, apply a small amount of ECL to any of the BNC connectors that may be exposed to moisture.
Installation Configuring power 7. Connect the instrument to the appropriate power receptacle Warning The Model 188CPS operates on 50-60 Hz power and may be configured for 115 or 230 VAC (100 or 200 VAC for Asian markets). The power requirements for each instrument is marked on the calibration sticker on the bottom of the instrument. Be sure your instrument is configured for your power source prior to plugging in the line cord.
2 Calibration Principle of operation The capacitance-based method of measuring a point operates by measuring the frequency of an oscillator, which is contained in the oscillator/transmitter unit. The calibration MIN and MAX settings correspond to the maximum and minimum oscillation frequencies, respectively, for a given gas/liquid configuration. As the liquid level varies in relation to the location of a plate sensor, the value of the plate sensor capacitance varies within a minimum and maximum value.
Calibration Calibration procedure Caution Three short beeps indicates a checksum failure of internal non-volatile memory. A checksum failure prevents the instrument from recovering calibration data. If this failure occurs, do not continue to use the instrument and contact an AMI Technical Support Representative for further assistance. 3. Fill the target vessel so that all plate pairs installed on the sensor are fully immersed in the liquid. 4.
Calibration Calibration procedure Variations in the dielectric with changing density For cryogenic liquids, the dielectric of the liquid and/or gas will change with a change in density. The amount of change is dependent on the properties of the specific cryogen. Figure 2-1 illustrates the variations in dielectric for nitrogen vs. pressure under saturated conditions.
Calibration Calibration procedure 18
3 Operation 1. Energize the instrument After completion of the Installation procedures, energize the instrument by placing the power toggle switch in the POWER position. As a power-up test, all LEDs will energize (green color), all relays contact pairs will close, and the instrument will sound a constant tone for 1.5 seconds. At the end of the power-up test, a series of beeps will occur. One beep indicates the calibration has been successfully recovered from internal memory.
Operation Sensor contamination 3. Observe the state of the front panel LEDs and rear panel relay contact pairs When a plate sensor is immersed in liquid, the corresponding front panel LED will energize as a green color and the rear panel relay contact pair will close. If a plate sensor is exposed to gas, the corresponding front panel LED will energize as an amber color and the rear panel relay contact pair will open.
Operation Sensor contamination Cold sensors exposed to humidified air can show erroneous readings due to the fact that the air contains moisture which can condense between the cold sensing plates. A small film of water can cause a shorted or partially shorted condition, which results in false readings. As the sensor warms, the moisture may evaporate and the sensor will again read correctly. This is a physical phenomenon and does not indicate any problem with your AMI level equipment.
Operation Sensor contamination 22
4 Troubleshooting Power switch LED not on 1. Ensure that the instrument is energized from a power source of proper voltage. Warning If the instrument has been found to have been connected to an incorrect power source, return the instrument to AMI for evaluation to determine the extent of the damage. Frequently, damage of this kind is not visible and must be determined using test equipment.
Troubleshooting Erratic or erroneous reading 3. Verify the input voltage selector switch on the instrument’s printed wiring board is in the proper position for the available power receptacle at the customer’s facility. Checking the input voltage selector requires removal of the top cover of the instrument. Observe the same safety procedures as presented in step 2. Erratic or erroneous point-sensor reading 1.
Troubleshooting Warranty Warranty All products manufactured by AMI are warranted to be free of defects in materials and workmanship and to perform as specified for a period of one year from date of shipment. In the event of failure occurring during normal use, AMI, at its option, will repair or replace all products or components that fail under warranty, and such repair or replacement shall constitute a fulfillment of all AMI liabilities with respect to its products.
Troubleshooting Return Authorization 26
Index B beeps W warranty 19 25 C calibration 15 accuracy 17 MAX 16 MIN 15 preparation 15 F features 1 front panel layout 3 I input voltage configuration 14 L LED amber 20 green 20 OFF 19, 20 red 20 M method of measurement P principle of operation 15 15 R rack mounting 12 rear panel layout 4 relay contacts specs 7 return authorization 25 S sensor connection 12 sensor contamination 20 sensor installation 12 specifications 7 system diagram 5 T troubleshooting erratic display 24 power LED off 23 repl
Index 28
