Keysight 34420A - Using *STB? to Read the Status Byte; To Interrupt Your Bus Controller Using SRQ; To Determine When a Command Sequence Is Completed

4 Remote Interface Reference
180 Keysight 34420A User’s Guide
Using *STB? to Read the Status Byte
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 IEEE-488 serial poll except that the “request service” bit (bit 6)
is not cleared if a serial poll has occurred. The *STB? command is not handled
automatically by the IEEE-488 bus 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 IEEE-488 SRQ interrupt.
To Determine When a Command Sequence is Completed
Either:
– Send the *OPC? (operation complete query) command and enter the result to
assure synchronization.
Or, to prevent holding the interface bus for commands that take longer to
execute (such as CALibrate commands), :
– Send a device clear message to clear the meter’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 your programming command string, and place the *OPC (operation
complete) command as the last command.