INFICON HPG400 ATM to High-Vacuum Gauge - Manual (Page 37)

tina31e1 (2004-05) HPG400 v1.om
37
6 Maintenance, Repair
DANGER
Caution: contaminated parts
Contaminated parts can be detrimental to health and environment.
Before beginning to work, find out whether any parts are contaminated.
Adhere to the relevant regulations and take the necessary precautions
when handling contaminated parts.
The gauge is factory-calibrated. Through the use in different climatic conditions,
fitting positions, aging or contamination and after exchanging the sensor (
→ 42)
a shifting of the characteristic curve can occur and readjustment can become nec-
essary. Only the Pirani part can be adjusted.
Adjustment is necessary if
• at atmospheric pressure, the output signal is <9.75 V or the display reads
< atmospheric pressure.
• when the vacuum system is vented, the output voltage reaches 9.75 V 1)
before
the measured pressure has reached atmospheric pressure (gauges with display
will show the error "5" at atmospheric pressure (Pirani sensor warning
→ 27).
• at atmospheric pressure, the digital value of the RS232C interface is
< atmospheric pressure.
• at atmospheric pressure, the digital value received by the bus controller of the
fieldbus gauges (DeviceNet or Profibus) is < atmospheric pressure.
• when the vacuum system is vented, the digital value of the RS232C interface
reaches its maximum before the measured pressure has reached atmospheric
pressure.
• when the vacuum system is vented, the digital value received by the bus con-
troller of the fieldbus (DeviceNet or Profibus) reaches its maximum before the
measured pressure has reached atmospheric pressure.
1)
The output signal is internally limited to +10.2 V.
Adjustment procedures for HPG400-SD/-SP and HPG400 gauges differ
and will be described separately.
The following procedures are described:
• HV adjustment Pirani
• ATM adjustment Pirani
• Pin approx. ш1.3 Ч 50 mm (e.g. a bent open paper clip)
The Pirani part is automatically adjusted by the hot cathode part when the gauge is
activated and a pressure value of 1 … 3×10
-3
mbar is reached for the first time.
6.1 Maintenance
6.2 Adjusting the Gauge
6.2.1 Pirani Adjustment
(HPG400)
Required tools
HV adjustment Pirani