SRS Labs QMS 100 Series, User Manual

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3-8 Communication Errors
SRS QMS Gas Analyzer
Jumper Protection Violation
Some calibration related commands are subject to jumper protection. Jumper JP100 on the digital (i.e.
top) board of the RGA electronics box can be used to enable/disable some of the tuning features of the
instrument. The jumper setting is checked before the command is executed and if calibration is disabled,
the Error LED is flashed, Bit 5 of RS232_ERR and Bit 0 of STATUS are set, and the command is not
executed. The jumper setting provides very solid protection against inadvertently tampering with
important calibration parameters stored in the RGA’s memory. Please refer to the “RGA Command
Set” list to find out which calibration commands are jumper protected.
Troubleshooting the RGA communications
The RGA’s communication interface includes a complete set of tools for troubleshooting
communications between a host computer and the spectrometer’s ECU during programming:
1. Visual Clue
The first clue of a communication error can be obtained watching the Error LED while communicating
with the ECU.
The ERROR_LED is flashed on/off two times every time a communication error is
detected.
2. Error Queries
The presence of a communication error can also be detected queering the contents of the STATUS
byte in the RGA ECU. The query command ER? returns the value of the STATUS Byte for analysis,
and a communication error is present if Bit 0 of STATUS is found set. The specific problem is
determined querying the bits of RS232_ERR byte using the
EC? which clears the RS232_ERR byte
and Bit 0 of STATUS at the end of its execution to provide a clean error-reporting slate.
Communication errors accumulate in the RS232_ERR byte as they occur and the byte can only be
cleared by reading it with the EC? command.
Note: Please refer to the “Error Byte Definitions” section of this chapter for a complete listing of the
error and status bytes of the RGA. Also consult the “Error Reporting Commands” list for details on the
EC and ER commands.