• Created : 
  • Modified : 
  • Category :  Agilent Knowledge Portal
  • Entry Type :  Article
  • Product Type :  GC Systems
  • Component :  GC System
  • Product Name :  6850 GC System 6890 GC System 7820 GC System 7890 GC System 8850 GC System 8860 GC System 8890 GC System
  • Task :  Troubleshooting
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How to Zero a Flow or Pressure Sensor in EPC Modules

Answer

This Information Applies to: Agilent GC systems.

Issue

The EPC gas control modules contain flow and pressure sensors that are calibrated at the factory. Zero offset requires periodic updating. Zeroing flow or pressure sensors may resolve discrepancies in EPC readouts if a value appears incorrect to the setpoint. 

Steps to Follow

For 6890, 7890, and 7820A GC systems

 

  
Caution: For flow sensors, verify that the gas is connected and flowing (turned on). For pressure sensors, disconnect the gas supply line at the back of the GC. Turning it off is not adequate; the valve may leak.

To zero a specific flow or pressure sensor

  1. Press [Options], scroll to Calibration, and press [Enter].
  2. Scroll to the module to be zeroed and press [Enter].
  3. Set the flow or pressure:
    • For flow sensors, verify that the gas is connected and flowing.
    • For pressure sensors, disconnect the gas supply line at the back of the GC.
  4. Scroll to the desired zero line.
  5. Press [On/Yes] to zero or [Clear] to cancel.
  6. Reconnect any gas line disconnected in step 3 and restore operating flows. 

To zero all pressure sensors in all modules

  1. Press [Service Mode], scroll to Diagnostics, and press [Enter].
  2. Scroll to Electronics and press [Enter].
  3. Scroll to Pneumatics and press [Enter].
  4. Disconnect the gas supply lines at the back of the GC. (Turning them off is not adequate; the valves may leak.)
  5. Scroll to Zero all pressure sensors.
  6. Press [On/Yes] to zero or [Clear] to cancel.
  7. Reconnect all gas supply lines and restore operating pressures.

 

For 8860, 8850 and 8890 GC systems

 

  
Caution: For flow sensors: Verify that the gas is connected and flowing (turned on). For pressure sensors: Disconnect the gas supply line at the back of the GC. Turning it off is not adequate; the valve may leak.

To zero a specific flow or pressure sensor

  1. From the Touchscreen or browser interface, press/click Settings > Calibration, then select the desired pneumatic zone to zero.
  2. Click On or Reset, next to the desired sensor to zero it.
    • For flow sensors, verify that the gas is connected and flowing.
    • For pressure sensors, disconnect the gas supply line at the back of the GC.
  3. Reconnect any gas line disconnected in the previous step and restore operating flows.

 

 
Learn how to effectively operate your Agilent GC system: 
GC-0GEN-1002v GC Basics e-learning course available from Agilent education
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