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Appendix

E: Status model Series 2600B System SourceMeter® Instrument

Reference Manual

E-18 2600BS-901-01 Rev. B / May 2013

Serial polling and SRQ

Any enabled event summary bit that goes from 0 to 1 sets bit B6 and generates a service request

(SRQ).

In your test program, you can periodically read the Status Byte to check if an SRQ has occurred and

what caused it. If an SRQ occurs, the program can, for example, branch to an appropriate subroutine

that will service the request.

SRQs can be managed by the serial poll sequence of the instrument. If an SRQ does not occur, bit

B6 (RQS) of the Status Byte Register remains cleared, and the program proceeds normally after the

serial poll is performed. If an SRQ does occur, bit B6 of the Status Byte Register is set, and the

program can branch to a service subroutine when the SRQ is detected by the serial poll.

The serial poll automatically resets RQS of the Status Byte Register. This allows subsequent serial

polls to monitor bit B6 for an SRQ occurrence that is generated by other event types.

For common commands and TSP commands, B6 is the MSS (Message Summary Status) bit. The

serial poll does not clear the MSS bit. The MSS bit stays set until all Status Byte Register summary

bits are reset.

SPE, SPD (serial polling)

For the GPIB interface only, the SPE and SPD general bus commands are used to serial poll the

System SourceMeter

instrument. Serial polling obtains the serial poll byte (status byte). Typically,

serial polling is used by the controller to determine which of several instruments has requested

service with the SRQ line.

Status byte and service request commands

The commands to program and read the Status Byte Register and Service Request Enable Register

are listed in Status byte and service request commands (on page E-18

). Note that the table includes

both common commands and their script command equivalents. For details on programming and

reading registers, see Programming enable and transition registers (on page

E-14) and Reading

registers (on page E-15).

To reset the bits of the Service Request Enable Register to 0, use 0 as the parameter value for the

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