INFICON MPG40x ATM to Ultra-High Vacuum Gauge - Manual (Page 25)

tina48e1-b (2008-10) MPG400-401.om
25
Problem Possible cause Remedy
Measuring signal
continually < 0.5 V
"Error low". No supply voltage. Turn on the power
supply.
Measuring signal
continually > 9.5 V
"Error high". Pirani measurement
element defective
(filament rupture). Replace the Pirani
element
(MPG400
→ 20)
(MPG401 → 23).
Electronics unit not cor-
rectly mounted. Mount the electronics
unit correctly
(MPG400
→ 20)
(MPG401 → 24).
The green lamp is ON and
the identification indicates
Pirani-only mode (mea-
suring signal continually
> 4.0 V)
"Pirani underrange". The cold cathode dis-
charge has not ignited. Wait until the gas dis-
charge ignites (in case of
contamination with insu-
lation layers, the cold
cathode may completely
fail to ignite).
(Cleaning
MPG400
→ 18
MPG401 → 21).
The MPG has only been
activated with
p < 3×10
—9 mbar.
Slightly increase the
pressure.
Measuring signal con-
tinually > 5 V or display
> 10
-3 mbar although
vacuum pressure is OK.
Pirani measurement cir-
cuit not adjusted, e.g.
due to severe contami-
nation. Readjust the Pirani
measurement circuit
(
→ 16). If adjustment
is impossible, replace the
Pirani element.
Measurement of heavy
gases.
Convert with the corre-
sponding formula
(
→ 30).
Severe outgassing in the
cold cathode measuring
chamber. Clean the measuring
chamber.
Measuring signal unstable. Gauge contaminated. Clean the gauge
(MPG400
→ 18)
(MPG401 → 21).
6.4 Troubleshooting