HP 34401A, Руководство пользователя

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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
•
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
interrupt by sending
*SRE 32
(status byte
enable register, bit 5).
Chapter 4 Remote Interface Reference
The SCPI Status Model
138