Fluke PM6685R Setting up the Counter to Report Status, Reading and Clearing Status, Status Byte

Using the Subsystems

as long as there is unfetched data in any of the status event registers.

–The Requested Service bit, RQS, is set true when a service request has been signalled. If you read the status byte via a Serial Poll, bit 6 represents RQS. Reading the status byte with a serial poll will set the RQS bit false, showing that the status byte has been read.

–The Master Summary Status bit, MSS, is set true if any of the bits that generates SRQ is true. If you read the status byte us- ing *STB?, bit 6 represents MSS. MSS re- mains true until all event registers are cleared and all queues are empty.

Setting up the Counter to Report Status

Include the following steps in your pro- gram when you want to use the status re- porting in CNT-8X:

–*CLS Clears all event registers and the er- ror queue

–*ESE <bit mask> Selects what condi- tions in the Standard Event Status register should be reported in bit 5 of the status byte

–:STATus:OPERation:ENABle <bit mask> Selects which conditions in the Operation Status register should be re- ported in bit 7 of the status byte

–:STATus:QUEStionable:ENABle <bit mask> Selects which conditions in the Questionable Status register should be reported in bit 3 of the status byte

–:STATus:DREGister0:ENABle <bit mask> Selects which conditions in Device Register 0 should be reported in bit 0 of the status byte

–*SRE <bit mask> Selects which bits in the status byte should cause a Service Request

A programming example using status re- porting is available in the Programming Examples in chapter 4.

Reading and Clearing Status

￿Status Byte

As explained earlier, you can read the sta- tus byte register in two ways:

Using the Serial Poll (IEEE-488.1 de- fined).

–Response:

–Bit 6: RQS message, shows that the counter has requested service via the SRQ signal.

–Other bits show their summary mes- sages

–A serial poll sets the RQS bit FALSE, but does not change other bits.

Using the Common Query *STB?

–Response:

–Bit 6: MSS message, shows that there is a reason for service request.

–Other bits show their summary mes- sages.

–Reading the response will not alter the status byte.

￿Status Event Registers

You read the Status Event registers with the following queries:

6-18 Status Subsystem