Stanford Research Systems RGA100, Operating Manual And Programming Reference

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9-12 Built-in Hardware Checks
SRS Residual Gas Analyzer
If a problem is detected in any of these checks Bit 4 of STATUS is set, QMF_ERR is
updated, and the Error LED is turned on.
Filament’’s Background Protection mode
STATUS Bit affected: 1
Error Byte affected: FIL_ERR
Error Reporting Command: EF?
Error Codes prefix: FL
Power-on check?: No
The filament is by far the most carefully protected component of the RGA.
When a electron emission current is requested, the RGA biases the ionizer and activates
the filament’’s heater until the desired electron current is achieved. The Filament LED is
turned on to indicate the presence of emission and the filament’’s ““Background Protection
Mode”” is automatically enabled to continuously (675Hz) monitor the operation of the
filament.
The conditions detected during Background Filament Protection are:
x
Filament not present (burnt or not installed)
x
Unable to set the requested emission current.
If any of these two error conditions is detected while the filament is on, the heater is
immediately shut down and the specific problem is reported as follows:
1. Bit 1 of STATUS is set.
2. FIL_ERR is updated
3. Filament LED is turned off.
4. Error LED is turned on.
5. The Leak and Burnt LED’’s are updated according to the specific problem
encountered.
6. The Electron Multiplier is also turned off.
Once detected, a filament error can only be cleared by successfully turning on the
filament to a finite electron emission current. It is always good practice trying again, if
the first attempt to get emission failed. Please refer to the FL command in the ““RGA
Command Set”” to get more details on the operation of the filament.
Important: Background Filament Protection is also automatically enabled while the
ionizer is in the Degas Mode.