Status Byte And Service Request (Srq) - Keithley 2500 User Manual

Models 2500 and 2502 User's Manual

Status byte and service request (SRQ)

Service request is controlled by two 8-bit registers; the status byte register and the service
request enable register.
Figure 14-3
Status byte and service request (SRQ)
Service
Request
Generation
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Figure 14-3
Status Summary Message
RQS
*STB? ESB
OSB
(B6)
Serial Poll (B77) (B5)
MSS
&
OR
__
*SRE OSB ESB
(B7) (B6) (B5)
*SRE?
OSB = Operation Summary Bit
MSS = Master Summary Status
RQS = Request for Service
ESB = Event Summary Bit
MAV = Message Available
QSB = Questionable Summary Bit
EAV = Error Available
MSB = Measurement Summary Bit
& = Logical AND
OR = Logical OR
shows the structure of these registers.
__
MAV QSB EAV
(B4) (B3) (B2) (B1)
&
&
&
&
__
QSB
MAV EAV
(B4) (B3) (B2) (B1)
Status Structure
Read by Serial Poll
MSB
Status Byte
Register
(B0)
Read by *STB?
&
Service
MSB
Request
Enable
(B0)
Register
14-7