Tektronix 070-9197-00 User Manual

Status and Events

PS2520G and PS2521G Programmer Manual

The programmable power supplies contain two queues: the Output
Queue and the Error/Event queue.

Following IEEE 488.2 protocols, the programmable power supplies
store query responses in the Output Queue. The power supply clears
and resets this queue each time it receives a new command or query
message after a message terminator. The controller must read a query
response before it sends the next command (or query) or it loses
responses to earlier queries.

When an error or event occurs, the Error/Event Queue stores the
message and sets bit 2 of the Status Byte Register high. Enabling this
bit by using the 

  command causes the event to signal the

GPIB controller with a Service Request (SRQ) signal.

The Error/Event Queue stores and reports the messages on a
first-in-first-out basis. The 

 or the 

 query reads the next item from the
Error/Event Queue. If the Error/Event Queue overflows, the last
message is 

 "  !; the queue cannot store or

report subsequent messages until it is read or cleared.

Table 11 lists the SCPI error messages for the programmable power
supplies. The listing includes the equivalent front-panel error code
along with a description of the error message.