# Zero Adjust

Navigation: Valve Firmware > Pressure Sensor > # Zero Adjust |

Zero Adjust allows for the compensation of the sensor offset voltage.

Note: A maximum offset voltage of +/- 1.4 V can be compensated. |

Parameter | Description
Zero Adjust.Sensor Selection | Select the sensor for the zero adjust: •Sensor 1 + 2 •Sensor 1 •Sensor 2
Zero Adjust.Target Pressure | Normally this parameter is set to 0 in case the process chamber is fully evacuated (pressure <=1‰ of sensor full scale). If not you can align the sensor value to a known pressure (displayed on another readout in the system). In this case set Target Pressure to the known pressure. Note: Target Pressure is in the unit of pressure, see relevant interface: Example serial interface RS232/485 Scaling
Zero Adjust.Execute | 1: Start the zero adjust 2: Clear offset value After executing value return to 0
Sensor 1.Enable Sensor 2.Enable | 0: It’s not possible to execute a zero adjust. A present offset value is ignored 1: It’s possible to execute a zero adjust. A present offset value is respected.
Sensor 1.Offset Value [SFS] Sensor 2.Offset Value [SFS] | Value which is deducted from the measured sensor value. The value is related to sensor full scale (0.1 means 10% of sensor full scale)

Location:

CPA Parameters
Pressure Sensor.Zero Adjust Pressure Sensor.Sensor 1.Zero Adjust Pressure Sensor.Sensor 2.Zero Adjust Pressure Sensor.Sensor 1.Zero Adjust Pressure Sensor.Sensor 2.Zero Adjust à or use ‘Pressure Sensor’ window

Performing a zero adjust:

1.Turn the gas flow off

2.Fully open the valve

3.Wait until the sensor signal is not shifting anymore. Refer to manual of sensor manufacturer for warm up time.

4.Wait until process chamber is evacuated.

| Do not perform Zero Adjust, if the base pressure of your vacuum system is higher than 1‰ of sensor full scale. We recommend disabling Zero Adjust function or using of Zero Adjust.Target Pressure other than 0.0 in this case. Otherwise incorrect pressure reading is the result.

5.Perform zero with setting of Zero Adjust.Execute to 1

6.Check parameter Actual Pressure if the pressure is shifted as expected