User`s manual

Relay Matrix Switch Command Reference 61Chapter 3
Clearing the Error Queue: An error number/message is removed from the
queue each time the SYSTem:ERRor? command is sent. The errors are
cleared first-in, first-out. When the queue is empty, each following
SYSTem:ERRor? command returns 0, "No error". To clear all error
numbers/messages in the queue, execute the *CLS command.
Maximum Error Numbers/Messages in the Error Queue: The queue holds
a maximum of 30 error numbers/messages for each switchbox. If the
queue overflows, the last error number/message in the queue is replaced
by -350, "Too many errors". The least recent error numbers/messages
remain in the queue and the most recent are discarded.
Example Querying the Error Queue
SYST:ERR?
!Query the error queue