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Page 27
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Operation
D397-01-880 Issue E
4.8.7
Active Inverted Magnetron (AIM) Gauge control
Note:
This section covers both standard (AIM-S) and linear (AIM-X) output gauges including low magnetic field
(-SL or -XL) and bakeable (type DN40CF) versions.
Note:
For a detailed specification and instructions regarding the use of the AIM-S and AIM-X gauges, refer to the
appropriate instruction manual (D146-41-885 or D146-61-880).
Active Inverted Magnetron (AIM) gauges are gas-dependent, cold-cathode ionisation gauges that measure pressures
in the range 1 x 10
-2
to 1 x 10
-9
mbar (7.5 x 10
-3
to 7.5 x 10
-10
Torr). There are a number of variants, offering standard
(AIM-S) and linear (AIM-X) outputs, low external magnetic field (AIM-SL and AIM-XL) variants for use on sensitive
scientific instruments and special bakeable tubes for use in UHV applications.
There are no additional setup options for AIM. (Refer to Default setup options (all gauges)
.
Please refer to
for the error and diagnostic information for the AIM gauge.
Table 19 - Error diagnostic monitoring ASG
Diagnostic message
Description
Over Range
(Gauge output >11.000 V)
Indicates that either the measured gas pressure is outside the range of the gauge, or
that there is a fault with the gauge.
Clear the error message, reduce the process pressure to within the range of the
gauge, scroll to the gauge display line and press 'Cycle'. If the gauge fails to give a
pressure readout it should be replaced.
ASG Cant Zero
Indicates that the gauge output is outside the range -100 mV to +100 mV.
The most likely cause of this error is either attempting to zero the gauge at too high a
pressure or a gauge fault.
Attempt to zero the gauge again and if the fault persists, the gauge should be
replaced.
Table 20 - Error/diagnostic monitoring AIM
Diagnostic messages
Description
Over Range
(Gauge output >11.000 V)
Indicates that the measured gas pressure is outside the range of the gauge or
the wrong gas type has been selected.
Check the gas selected is correct, switch off the gauge, clear the error, reduce
the process pressure to within the range of the gauge and press 'Cycle'.
If the error persists, there is a fault with the gauge and the electronics module
should be replaced.
Under Range
(Gauge output <0.025 V)
Indicates that there is a fault with the gauge or cable. Replace the cable and if
the fault persists, the electronics module should be replaced.
Striking
Indicates that the gauge is attempting to strike.
TIC will continue in this mode for up to 15 minutes.
Not Struck
Indicates that the gauge failed to strike within 15 minutes.
This is most likely to be because of the gauge tube becoming contaminated.
The gauge tube should be inspected for signs of contamination or debris. If the
anode and cathode are not bright, the gauge should be cleaned or the
electrodes replaced (D145-45-802 or D146-61-802) as described in the AIM
instruction manual.
