Stanford Research Systems RGA100, Operating Manual And Programming Reference

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Programming the RGA Head 6-27
SRS Residual Gas Analyzer
LED is turned off and the Error LED is turned on. The problem is immediately diagnosed
visually as a failure in the 24V External P/S check. A multimeter could be used to check
the output of the external power supply and determine the nature of the problem;
however, the computer could also be used to diagnose the problem using the query
commands:
The ER query command returns a STATUS Byte with bit 6 set indicating a 24V P/S
problem. The EP query command is then used to query PS_ERR. Bit 6 of PS_ERR is
found set (Error Code: PS6) indicating that the P/S output is less than the acceptable
minimum of 22 V.
This error is also immediately reported by the RGA Windows software as an Error Code:
PS6, and the RGA Troubleshooting section can be consulted to solve the problem.
Example #2:
The RGA is idling between scans, waiting for commands from the computer, when
suddenly a vent-valve is accidentally opened and the vacuum system is pressurized. The
Background Filament Protection mode immediately detects the problem and turns off the
filament. The change is easily detected because the Filament LED turns off, and the Error
and Leak LED’’s simultaneously turn on.
A visual inspection of the red LED’’s is all that is needed in this case to detect and
diagnose the problem; however, a computer could do the same diagnosis with the help of
the query commands:
The ER? command, used to monitor the STATUS byte regularly, returns a non-zero byte
value. Further analysis, shows that bit 1 is set indicating a filament problem. The EF?
command is then used to read in the value of FIL_ERR. Bit 6 is found set indicating that
the filament was unable to set the requested emission current and had to be shut down
(Error Code: FL6). The problem is quickly diagnosed as an overpressure using the RGA
Troubleshooting chapter directions.
The error is also immediately reported by the RGA Windows software as Error Code:
FL6, and the RGA Troubleshooting section can be consulted to solve the problem.
Example #3:
The RGA is turned on and, after all the internal checks are performed, the green Power
LED and the Error LED are turned on. The red LED signals the operator that a problem
was detected. A 24V P/S error is not expected since the Power LED is on. The ER?
command returns a STATUS byte with bit 4 set, pointing to a quadrupole mass filter
problem. The command EQ? is used to read in the QMF_ERR byte. Bit 7 is found set
indicating that the RF driver is unable to set the maximum RF value available to the RGA
(Error code RF7 in Troubleshooting Chapter). A quick visual inspection of the RGA head
shows that the ECU is not pushed all the way into the probe and no actual connection
exists between the rods and the RF driver.
This error is also immediately reported by the RGA Windows software as Error Code:
RF7, and the RGA Troubleshooting section can be consulted to solve the problem.
Example #4:
The user notes that the Error LED flashes every time the ID? command is sent to the