Stanford Research Systems RGA100, Operating Manual And Programming Reference

Page: 132 / 362

6-28 Programming the RGA Head
SRS Residual Gas Analyzer
RGA and the ID string is never returned (i.e. receive timeout). The STATUS byte
returned by the ER command has the bit 0 set as expected for a communications problem.
The specific communications problem is diagnosed using the EC? command. Bit 0 of
RS232_ERR is found set indicating that a bad command is being detected by the RGA.
The user checks the communications program and finds out that, due to mistyping, the
IM? string is being sent to the RGA instead of ID?. The problem is easily corrected.
Error Checking Programming tips
x
Keep a close eye on the Error LED’’s while programming the RGA. Diagnose
problems as soon as they are detected.
x
Even though a lot of internal checks are performed by the microprocessor, not all
possible internal error conditions are accounted for.
x
The values of the Error Bytes often change after an Error Byte query command is
executed. Some query commands update the byte value after performing a fresh test
on the hardware, while others clear error bits, after they are read, to provide a clean
error-reporting slate. Please see the Error Reporting Commands list for details.
x
It is good programming practice to check the value of the STATUS byte whenever it
is returned at the end of command execution.
x
In cases were a hardware error is reported at the end of a command attempt the
command one more time before declaring a hardware problem.