Using The Operation Complete Commands - HP E4418B Programming Manual

Using the Operation Complete Commands

The *OPC? and *OPC commands allow you to maintain synchronization
between the computer and the power meter. The *OPC? query command
places an ASCII character 1 into the power meter's output queue when all
pending power meter commands are complete. If your program reads this
response before continuing program execution, you can ensure
synchronization between one or more instruments and the computer.
The *OPC command sets bit 0 (Operation Complete) in the Standard
Event Status Register when all pending power meter operations are
complete. By enabling this bit to be reflected in the Status Register, you
can ensure synchronization using the HP-IB serial poll.
Procedure
• Send a device clear message to clear the power 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 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
power meter for an SRQ interrupt by sending *SRE 32 (status byte
enable register, bit 5).
HP E4418B/E4419B Programming Guide
Power Meter Remote Operation
Status Reporting
1-89