Agilent Technologies E1301B Synchronizing an External Computer Instruments, Enter 70909A, 60 END

Synchronizing an

External Computer

and Instruments

The *OPC? and *OPC commands (operation complete commands) allow you to maintain synchronization between an external computer and an instrument. The *OPC? query places an ASCII character 1 into the instrument’s output queue when all pending instrument operations are finished. By requiring the computer to read this response before continuing program execution, you can ensure synchronization between one or more instruments and an external computer.

The *OPC command sets bit 0 (Operation Complete Message) in the Standard Event Status Register when all pending instrument operations are finished. By enabling this bit to be reflected in the Status Byte Register, you can ensure synchronization using the GPIB serial poll function.

Example: Synchronizing an External Computer and Two Instruments using the OPC? query.

This example uses a D to A Converter module (DAC) at secondary address 09 and a Scanning Voltmeter at secondary address 03. The application requires the DAC to output a voltage to a device under test. After the voltage is applied, the voltmeter measures the response from the device under test. The *OPC? command ensures that the voltage measurement will be made only after the voltage is applied by the DAC.

10 OUTPUT 70909;"SOUR:VOLT1 5;*OPC?"

!Configure DAC to output 5 volts on channel 1; place 1 in output

!queue when done

20 ENTER 70909;A

!Wait for *OPC? response

30 OUTPUT 70903;"MEAS:VOLT:DC? (@104)"

!Measure DC voltage on device under test

40ENTER 70903;A

!Enter voltage reading

50 PRINT A

!Print reading

60 END

6-12 Controlling Instruments Using GPIB