Adjusting The Gauge - Agilent Technologies FRG-700 User Manual

Technical Information

Adjusting the Gauge

The gauge is factory-calibrated. If used under different climatic conditions, through
extreme temperatures, aging or contamination, and after exchanging the sensor,
the characteristic curve can be offset and readjustment may become necessary.
The cold cathode measuring circuit, which is dominant for low pressures
(<1×10
Pirani measuring circuit can be adjusted. Any adjustment has a negligible effect on
the pressure range between approx. 10
Tools required
Procedure
1 If you are using a seal with centering ring and filter, check that they are clean or
replace them if necessary.
2 Put the gauge into operation (if possible, in the position, in which it will be used
later on).
3 Evacuate the vacuum system to p << 10
4 Turn the nameplate counter-clockwise until the mechanical stop is reached.
5
While depressing the pin with the cylindrical pin, adjust the <HV> potentiometer
32 Agilent Inverted Magnetron Pirani Gauge FRG-700 and FRG-702 User Manual
-3 mbar), is factory-calibrated and cannot be adjusted. By way of contrast, the
-2
mbar and 10
Screw driver 1.5 mm

Cylindrical pin ø≈3 mm

-4 mbar, and then wait 10 minutes.
2
mbar.