HP 34401A User Manual page 138

Chapter 4 Remote Interface Reference
The SCPI Status Model
Using to Read the Status Byte
*STB?
The *STB? (status byte query) command is similar to a serial poll except
it is processed like any other instrument command. The *STB? command
returns the same result as an
"request service" bit (bit 6) is not cleared if a serial poll has occurred.
The *STB? command is not handled automatically by the
interface hardware and the command will be executed only after
previous commands have completed. Polling is not possible using the
*STB? command. Using the *STB? command does not clear the status
byte summary register.
To Interrupt Your Bus Controller Using SRQ
Send a bus device clear message.
Clear the event registers with the *CLS (clear status) command.
Set the *ESE (standard event register) and *SRE (status byte
register) enable masks.
Send the *OPC? (operation complete query) command and enter the
result to assure synchronization.
Enable your bus controller's
To Determine When a Command Sequence is Completed
Send a device clear message to clear the multimeter's output buffer.
Clear the event registers with the *CLS (clear status) command.
Enable "operation complete" using the *ESE 1 command (standard
event register).
Send the *OPC? (operation complete query) command and enter the
result to assure synchronization.
Send your programming command string, and place the *OPC
(operation complete) command as the last command.
Use a serial poll to check to see when bit 5 (standard event) is set
in the status byte summary register. You could also configure the
multimeter for an
SRQ
enable register, bit 5).
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serial poll except that the
IEEE-488
interrupt.
IEEE-488 SRQ
interrupt by sending *SRE 32 (status byte
bus
IEEE-488