Teledyne 2002 instruction manual Zero Coefficient Adjustment

An important point to be noted is the fact that after the adjustment, the new calibration coefficient is only in temporary memory. If the instrument were unplugged at this point, it would revert back to the original displayed value upon restarting. Place the Model 2002 back in the RUN mode to store all of the current calibration coefficients in permanent memory.

To perform a full calibration on the Model 2002 system, first use the Zero Coefficient Adjustment Procedure. Followed by the Midrange Coefficient Adjustment Procedure, and finally perform the Atmosphere Coefficient Adjustment Procedure.

Zero Coefficient Adjustment

The zero coefficients corrects for the constant power level which is present over the entire pressure range. Typically, this adjustment corrects for low pressure errors. The instrument will need to be re-zeroed often if measurements are being made in the 10-4 Torr range, especially if the ambient temperature changes. The transducer may have a temperature coefficient of up to 2x10-4 Torr/oC. The instrument remote zero input will allow an external gauge such as an ion gauge to automatically re-zero the Model 2002 whenever the pressure drops below the desired pressure level (if it has a TTL output).

NOTE: Do not attempt to zero the Model 2002 in pressures above 10-2 Torr; the microprocessor will not accept a zero above this pressure.

To manually adjust the zero uses the following procedure:

1.If possible, evacuate the vacuum system into the low 10-6 Torr (1.33x10-6 mbar) range or as low as possible below 10-4 Torr.

2.Allow the sensor to operate in this condition for a minimum of 15 minutes.

149-072011 Model 2002 Vacuum Gauge Page 11 of 38