Keithley System SourceMeter 2601B, Справочное руководство

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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
command (for example,
*SRE 0
or
status.request_enable = 0
).
Status Byte and Service Request Enable Register commands
Command Description
*STB?
or
print(status.condition)
Read the Status Byte Register.
*SRE mask
or
status.request_enable = mask
Program the Service Request Enable Register where
mask
= 0 to 255.
*SRE?
or
print(status.request_enable)
Read the Service Request Enable Register.