Programming instructions

Programming the Status Register System
Accessing Status Register Information
Chapter 3108
If a program enables the controller to detect and respond to service requests, it should
instruct the controller to perform a serial poll when SRQ is true. Each device on the bus
returns the contents of its status byte register in response to this poll. The device whose RQS
bit is set to 1 is the device that requested service.
NOTE When you read the signal generator’s Status Byte Register with a serial poll,
the RQS bit is reset to 0. Other bits in the register are not affected.
If the status register is configured to SRQ on end-of-measurement and the
measurement is in continuous mode, then restarting a measurement (INIT
command) can cause the measuring bit to pulse low. This causes an SRQ when
you have not actually reached the “end-of-measurement” condition. To avoid
this, do the following:
1. Send the command INITiate:CONTinuous OFF.
2. Set/enable the status registers.
3. Restart the measurement (send INIT).
Status Register SCPI Commands
Most monitoring of signal generator conditions is done at the highest level, using the IEEE
488.2 common commands listed below. You can set and query individual status registers using
the commands in the STATus subsystem.
*CLS (clear status) clears the Status Byte Register by emptying the error queue and
clearing all the event registers.
*ESE, *ESE? (event status enable) sets and queries the bits in the Standard Event Enable
Register which is part of the Standard Event Status Group.
*ESR? (event status register) queries and clears the Standard Event Status Register
which is part of the Standard Event Status Group.
*OPC, *OPC? (operation complete) sets the Standard Event Status Register to zero so it
can monitor the completion of all commands. The query stops any new commands from
being processed until the current processing is complete, then returns a ‘1’.
*PSC, *PSC? (power-on state clear) sets the power-on state so that it clears the Service
Request Enable Register, the Standard Event Status Enable Register, and device-specific
event enable registers at power on. The query returns the flag setting from the *PSC
command.