Tektronix KEITHLEY SourceMeter 2606B Reference Manual page 263

Section 10: Status model
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Bit B5, Event Summary Bit (ESB): When set, indicates that an enabled standard event has
occurred.
•
Bit B6, Request Service (RQS)/Master Summary Status (MSS): When set, indicates that an
enabled summary bit of the Status Byte Register is set. Depending on how it is used, bit B6 of the
Status Byte Register is either the Request for Service (RQS) bit or the Master Summary Status
(MSS) bit:
▪
When using a USB or VXI-11 serial poll sequence of the 2606B to obtain the status byte
(serial poll byte), B6 is the RQS bit. See
using the serial poll sequence.
▪
When using the *STB? common command or status.condition to read the status byte, B6 is
the MSS bit.
•
Bit B7, Operation Summary (OSB): When set, indicates that an enabled operation event
has occurred.
Service Request Enable Register
The Service Request Enable Register controls the generation of a service request. This register is
programmed by the user and is used to enable or disable the setting of bit B6 (RQS/MSS) by the
Status Summary Message bits (B0, B1, B2, B3, B4, B5, and B7) of the Status Byte Register. As
shown in Status Byte Register, a logical AND operation is performed on the summary bits (&) with the
corresponding enable bits of the Service Request Enable Register. When a logical AND operation is
performed with a set summary bit (1) and with an enabled bit (1) of the enable register, the logic "1"
output is applied to the input of the logical OR gate and, therefore, sets the MSS/RQS bit in the
Status Byte Register.
You can set or clear the individual bits of the Service Request Enable Register by using the *SRE
common command or status.request_enable. To read the Service Request Enable Register,
use the *SRE? query or print(status.request_enable). The Service Request Enable Register
clears when power is cycled or a parameter value of 0 is sent with a status request enable command
(for example, a *SRE 0 or status.request_enable = 0 is sent). The commands to program and
read the SRQ Enable Register are listed in
page 10-17).
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 occurred and what
caused it. If an SRQ occurred, the program can, for example, branch to an appropriate subroutine
that services the request.
10-16
Model 2606B System SourceMeter® Instrument Reference Manual
Serial polling and SRQ
Status byte and service request commands
2606B-901-01 Rev. C November 2021
(on page 10-16) for details on
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