Specifications

Troubleshooting the RGA communications 6-11
SRS Residual Gas Analyzer
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 head during
programming:
1. Visual Clue
The first clue of a communication error can be obtained watching the Error LED while
communicating with the head.
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 head. 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.