Keithley 2015, Service Manual, Page: 146 / 158

B-20 Calibration Reference
Error queue
As with other Model 2015 errors, any calibration error will be reported in the bus error queue.
You can read this queue by using the :SYST:ERR? query. The Model 2015 will respond with the
appropriate error message, as summarized in Table B-5.
Status byte EAV (Error Available) bit
Whenever an error is available in the error queue, the EAV (Error Available) bit (bit 2) of the
status byte will be set. Use the *STB? query or serial polling to obtain the status byte, then test
bit 2 to see if it is set. If the EAV bit is set, an error has occurred, and you can use the
:SYST:ERR? query to read the error and at the same time clear the EAV bit in the status byte.
Generating an SRQ on error
To program the instrument to generate an IEEE-488 bus SRQ when an error occurs, send the
following command: *SRE 4. This command will enable SRQ when the EAV bit is set. You can
then read the status byte and error queue as outlined above to check for errors, and to determine
the exact nature of the error.