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Kurt J. Lesker 979 Series Operation And Maintenance Manual

Atv (atmosphere to vacuum) transducer
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Series 979 Atmosphere to
Vacuum Transducer
Operation and
Maintenance Manual

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Summary of Contents for Kurt J. Lesker 979 Series

  • Page 1 Series 979 Atmosphere to Vacuum Transducer Operation and Maintenance Manual...
  • Page 3 Series 979 Atmosphere to Vacuum Transducer Part # 100014438 Series 979 ATV Transducer...
  • Page 4 For more information or literature, contact: Kurt J. Lesker Company 1925 Route 51 Clairton, PA 15025-3681 USA Phone: 1-412-387-9200 1-800-245-1656 Fax: 1-412-384-2745 ©2003 by the Kurt J. Lesker Company, All rights reserved. Series 979 ATV Transducer...

  • Page 5: Table Of Contents

    Table of Contents Package Contents ..............9 Symbols Used in this Manual ..........10 Safety Precautions ..............11 General Specifications ............13 Feature and Control Locations ..........14 About the 979 ATV Transducer ..........15 Typical Applications for the 979 ATV Transducer ..... 16 Installing the 979 ATV Transducer ...........
  • Page 6 Firmware Version Hot Cathode – FVHC ........... 28 Hardware Version MicroPirani – HV ..........28 Hardware Version Hot Cathode – HVHC ........... 28 Model – MD ..................28 Serial Number – SN ................. 29 Time On – TIM1, TIM2 ..............29 Transducer Status –...
  • Page 7 Accessories and Part Replacement ........47 Notes ..................48 Appendix: How the 979 ATV Transducer Works....... 49 Hot Cathode Ionization Sensor ............... 49 Pirani Sensor ..................50 MicroPirani Sensor ................. 51 Series 979 ATV Transducer...
  • Page 8 Series 979 ATV Transducer...

  • Page 9: Package Contents

    If any items are missing from the package, call Kurt J. Lesker Customer Service at 1-412-387-9200 or 1-800-245-1656. Do not return the product to Kurt J. Lesker unless specified to do so by Kurt J. Lesker Customer Service. Kurt J. Lesker customer service and support: Kurt J.

  • Page 10: Symbols Used In This Manual

    Symbols Used in this Manual CAUTION: Risk of electrical shock. CAUTION: Refer to the manual. Failure to heed the message could result in personal injury, serious damage to the equipment, or both. Calls attention to important procedures, practices, or conditions. Series 979 ATV Transducer...

  • Page 11: Safety Precautions

    Do not substitute parts or modify instrument. Do not install substitute parts or perform any unauthorized modification to the instrument. Return the instrument to an Kurt J. Lesker Calibration and Service Center for service and repair to ensure that all of the safety features are maintained.
  • Page 12 Allow only qualified technicians to service the transducer. Users should not remove covers, casing, or plug-in components. Injury may result. A qualified technician must perform any part replacement or internal adjustments. Keep the unit free of contaminants. Do not allow contamination of any kind to enter the unit before or during use.

  • Page 13: General Specifications

    General Specifications Measuring range 5x10 to atmosphere Set point range 5x10 to 100 Torr Analog out 1 to 9 VDC Maximum pressure 1000 Torr Repeatability (Typical) 1x10 to 10 Torr +/- 5% of reading to 100 Torr +/- 2% of reading 100 to atm +/- 10% of reading Accuracy (Typical) to 10...

  • Page 14: Feature And Control Locations

    Feature and Control Locations All user access is through the 15-pin D-sub connector. See the RS-485 Command Set section for more information. The POWER LED indicates when power is applied to the 979 ATV Transducer. The FILAMENT ON LED indicates when power is applied to the transducer filament.

  • Page 15: About The 979 Atv Transducer

    About the 979 ATV Transducer The 979 ATV Transducer is designed to measure vacuum chamber pressures as part of a user’s designed system processes. It combines a Hot Cathode sensor to measure pressures from 5x10 to 3x10 Torr and a MicroPirani sensor to measure pressures from 1x10 to atmosphere.

  • Page 16: Typical Applications For The 979 Atv Transducer

    Typical Applications for the 979 ATV Transducer ♦ Measure high vacuum pressure. ♦ Control system pressure using digital communications or analog output as input to an automatic pressure controller. ♦ Measure foreline and roughing pressures generated by mechanical vacuum pumps. ♦...

  • Page 17: Installing The 979 Atv Transducer

    Installing the 979 ATV Transducer ATV Transducer Installation Location Locate the 979 ATV Transducer where it can measure chamber pressure. Install the device away from pumps and gas sources so it will give the most representative pressure values. If the Hot Cathode sensor is going to be baked out, the four screws on the panel closest to the flange will need to be removed (see the Bakeout section for details).

  • Page 18: Contamination

    Contamination Locate and orient the 979 ATV Transducer where contamination is least likely. For example, if the 979 ATV Transducer is mounted directly above a source of evaporation, the vapor could contaminate the sensor elements and cause the calibration to shift. Whenever possible, install the 979 ATV Transducer with the vacuum port facing down to keep particulates or liquids from entering the device.

  • Page 19: Electrical Connection

    Electrical Connection Use a cable with a female, 15-pin, high-density D-sub connector with strain reliefs to ensure proper electrical connection and to reduce stress on the connectors. Ensure a low impedance electrical connection between the 979 sensor body and the grounded vacuum system to shield the sensor from external electromagnetic sources.

  • Page 20: 979 Atv Transducer Electrical Connections Table

    979 ATV Transducer Electrical Connections Table The digital communications connections are pins 1 and 2. RS-485 uses pin 1 for RS485(-) and pin 2 for RS485(+). RS485 - RS485 + POWER + (24V) PIN 1 PIN 5 POWER - ANALOG OUT + ANALOG OUT - RELAY 1 N.O.
  • Page 21 Pressure reading gas dependence: The MicroPirani is based on measurement of thermal conductivity; therefore, the MicroPirani readout depends on the gas type and concentration. The MicroPirani is calibrated for Nitrogen gas, and will read a higher pressure when exposed to atmospheric air. The Hot Cathode sensor is based on measurement of gas ionization;...

  • Page 22: Operation

    Operation The 979 ATV Transducer operation parameters are preset at the factory. The table below shows the factory default settings. Use the commands described on the following pages to change parameter settings as necessary. The user interface to the 979 ATV Transducer is through RS-485 serial communications.

  • Page 23: Rs-485 Protocol

    RS-485 Protocol The 979 supports 2400, 4800, 9600, and 19200 baud rates (factory default: 9600). The data format is 8 data bits, no parity, and one stop bit. Standard Addresses Valid addresses are 3 digits, 001 to 253 (factory default: 253). Universal Addresses The 979 receives and responds to commands sent to address 254.

  • Page 24: Response Syntax (Ack/Nak)

    Response Syntax (ACK/NAK) The ASCII characters 'ACK' or 'NAK' preface the query or command response string. The ACK sequence signifies the message was processed successfully. The NAK sequence indicates there was an error. The response to a query or a successful command is: @<device address>ACK<data>;FF The response to a message with an error is: @<device address>NAK<NAK code>;FF...

  • Page 25: Rs-485 Command Set

    RS-485 Command Set The query and command formats shown in this section are examples; the values may vary for the user’s installation. Set Up Commands Active Filament – AF The AF command returns which of the Hot Cathode sensor’s two filaments is active, or selects between the sensor’s two filaments.

  • Page 26: Baud Rate - Br

    Baud Rate – BR The BR command returns or sets the baud rate of the communications protocol. The 979 responds to this command at the present baud rate; however, the user will need to change the baud rate on the host to ensure future commands are sent at the same rate.

  • Page 27: Rs Delay - Rsd

    RS Delay – RSD The RSD command enables or disables a delay of up to 5 milliseconds between recieve and transmit mode. Values: OFF, ON (default OFF) Query: @001RSD?;FF Query Response: @001ACKOFF;FF Command: @001RSD!ON;FF Command Response: @001ACKON;FF Test RS485 – TST The TST command flashes the filament power LED ON and OFF, in order to visually identify the unit.

  • Page 28: Status Commands

    Status Commands Device Type – DT The DT command returns the transducer device type. Query: @001DT?;FF Query Response: @001ACKMP-HC 979;FF Filament Status – FS The FS command returns the operating status of the active filament. To select between the sensor’s two filaments, see Active Filament – AF (Set Up Commands section).

  • Page 29: Model - Md

    Model – MD The MD command returns the 979 model number. Query: @001MD?;FF Query Response: @001ACK979;FF Serial Number – SN The SN command returns the 979 serial number. Query: @001SN?;FF Query Response: @001ACK000012345;FF Time On – TIM1, TIM2 The TIM1 command returns the number of hours the transducer has been on. The TIM2 command returns the number of hours each filament on the Hot Cathode has been on, or clears the time on both filaments to allow the user to replace the sensor.

  • Page 30: Transducer Temperature - Tem1, Tem2

    Transducer Temperature – TEM1, TEM2 The TEM1 command returns the MicroPirani on-chip sensor temperature in C. The TEM2 command returns the Hot Cathode on-chip sensor temperature C. If the temperature exceeds 70 C, the ambient temperature may be too high or the filament power is too high (nominal temperature rise is 30 C above ambient).

  • Page 31: Pressure Reading - Pr1, Pr2, Pr3

    Pressure Reading – PR1, PR2, PR3 The pressure reading command returns the measured pressure from either the MicroPirani (PR1), the Hot Cathode (PR2), or a combination of both (PR3). For pressures above 3x10 Torr, the PR3 reading is the same as PR1. For pressures below 1x10 Torr, the PR3 reading is the same as PR2.

  • Page 32: Enable Set Point - En1, En2, En3

    Set Point Direction – SD1, SD2, SD3 The set point direction command returns or sets the direction of the set point relay. If the value is BELOW, then the relay will be energized below the set point value. (See Set Point Value – SP1, SP2, SP3 and Hysteresis Value – SH1, SH2, SH3, above.) Values: BELOW, ABOVE (default: BELOW)

  • Page 33: Protect Set Point - Pro

    Protect Set Point – PRO The PRO command returns or sets the pressure value at which the Hot Cathode will turn itself off to prevent sensor damage. The protect set point cannot be disabled and is valid during degas. NOTE: If the control set point is enabled, do not set the protect set point below 3x10 Torr.

  • Page 34: Gas Type Calibration - Gt

    Gas Type Calibration – GT The GT command sets gas type for measurement on the MicroPirani. The MicroPirani measures thermal conductivity; using the gas calibration compensates for gas errors. Values: NITROGEN, AIR, ARGON, HYDROGEN, HELIUM, H20 (default: NITROGEN) Query: @001GT?;FF Query Response: @001ACKAIR;FF Command:...

  • Page 35: Degassing The Sensor

    Degassing the Sensor Sensitivity of the Hot Cathode sensor may drift if the sensor elements become contaminated with system process gasses. This becomes more of a problem the lower the pressure being measured (i.e., (≤10 Torr). To rid the sensor elements of the excess system process gasses, periodically degas the sensor.

  • Page 36: Sensitivities Relative To Nitrogen

    Sensitivities Relative to Nitrogen If using a gas other than air/nitrogen in the system, then the user will need to change the gas correction factor for the Hot Cathode to provide an accurate pressure reading (see Gas Correction – GC in the Set Up Commands section).

  • Page 37: Analog Output

    Analog Output The 979 ATV Transducer analog voltage signal pins are 5 (+) and 6 (-). Connect them to a differential input. The transducer provides 2 analog output scales: DAC1 is 0.5V/decade; DAC2 is 0.774V to 10V. Do not connect the negative side of the analog output (pin 6) to the power supply return (pin 4) or to any other ground.

  • Page 38: Pressure To Voltage Table

    DAC1 Pressure to Voltage Table V olts V olts P ressure (Torr) P ressure (Torr) 0.50 3.95 1.0E -10 8.0E -04 0.65 4.00 2.0E -10 1.0E -03 0.80 4.15 4.0E -10 2.0E -03 0.95 4.30 8.0E -10 4.0E -03 1.00 4.45 1.0E -09 8.0E -03...
  • Page 39 To calculate Pressure from Voltage: V-7.75 P=10 Where: C=0 for mBar C=2 for Pascal C=-0.125 for Torr Series 979 ATV Transducer...
  • Page 40 DAC2 Pressure to Voltage Table Series 979 ATV Transducer...

  • Page 41: Leak Detection

    Leak Detection Its inherent sensitivity to gas type makes the 979 ATV Transducer useful for detecting leaks at rates greater than 10 std cc/sec of helium. It is a useful complement to a mass spectrometer leak detector, which locates smaller leaks.

  • Page 42: Bakeout/Sensor Replacement

    Bakeout/Sensor Replacement CAUTION: Disconnect the power supply before disassembly! Lethal voltages and currents may be present while the circuit is operating. Only a qualified technician should replace or adjust electronic components. Bakeout If building the system for the first time, or after performing routine maintenance, the system may need to be baked out to remove any water vapor.

  • Page 43: Sensor Replacement

    To re-assemble the electronics, use the disassembly steps in reverse order. Sensor Replacement Before disassembling the electronics for sensor replacement, use the Time On – TIM1, TIM2 command (described in the Status Commands section) to clear the filament time. To disassemble the electronics for sensor replacement, use the procedure in the Bakeout section.

  • Page 44: Maintenance And Troubleshooting

    Maintenance and Troubleshooting Maintenance and Troubleshooting Table i l a – – i l a i l a – e i l a l i g i l a l i e l i a l i Series 979 ATV Transducer...

  • Page 45: Cleaning The 979 Atv Transducer Case And Sensor Tube

    x i f Cleaning the 979 ATV Transducer Case and Sensor Tube The finish of the 979 ATV Transducer case is designed to resist many laboratory solvents; clean the case with water or alcohol. Take care to prevent a liquid from entering the electronic enclosure. Roughing pump oils and other fluids condensing or decomposing on the heated filament can contaminate the sensors elements.

  • Page 46: Sensor Test Resistance Values Table

    Sensor Test Resistance Values Table Resistance <2 Ω Filament 1 or 2 to same filament <1 Ω Grid to grid >20M Ω Grid to collector or either filament >20M Ω Any pin to the sensor body The figure below shows the locations of the pins. COLLECTOR GRID LOCATOR...

  • Page 47: Accessories And Part Replacement

    Accessories and Part Replacement Description Part Number Sensor with 2.75” CF K97921 Sensor with 1.33” CF K97911 Sensor with NW40 KF K97951 Sensor with NW25 KF K97941 Sensor with NW16 KF K97931 Operation and Maintenance Manual 100014438 Series 979 ATV Transducer...

  • Page 48: Notes

    Notes: Series 979 ATV Transducer...

  • Page 49: Appendix: How The 979 Atv Transducer Works

    Appendix: How the 979 ATV Transducer Works The Series 979 ATV Transducer is a combination of two different types of pressure sensors: the Hot Cathode and the MicroPirani. The Hot Cathode sensor measures pressure indirectly from ion currents, which is proportional to gas density and pressure.

  • Page 50: Pirani Sensor

    Pirani Sensor The Pirani sensor is a type of thermal conductivity sensor. It consists of a hot wire suspended from supports. This wire loses thermal energy in three ways: ♦ Thermal conduction through the gas, which is pressure dependent ♦ End loss to the supports ♦...

  • Page 51: Micropirani Sensor

    Implanted resistors Silicon R+ΔR R-ΔR Depletion region R-ΔR R+ΔR Diaphragm MicroPirani Sensor The MicroPirani sensor functions the same as a traditional Pirani sensor, but instead of a heated wire, a thin film Nickel resistive element is deposited onto a silicon substrate. This heated filament is maintained at a constant temperature above the ambient temperature of the substrate.
  • Page 52 Series 979 ATV Transducer...
  • Page 53 Series 979 ATV Transducer...
  • Page 54 Series 979 ATV Transducer...

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