STATus Command
PCR-WE Interface Manual
205
Status byte register
The status byte register stores STB and RQS (MSS) messages as defined by the
IEEE 488.1 standard. The status byte register can be read by using IEEE 488.1 serial
polling or the IEEE 488.2 common command *STB?.
When the controller executes serial polling, bit 6 responds with request service (RQS).
The status byte value is not changed by serial polling.
*STB? makes the device transmit the contents of the status byte register and the
master status summary (MSS) message.
*STB? does not change the status byte, MSS, and RQS.
Bit
Bit
weight
Bit name
Description
0
1
Reserved
Reserved for future use by IEEE 488. The bit value is
notified as zero.
1
2
Reserved
2
4
Error/Event Queue
If data exists in the error or event queue, this bit is set to
true.
3
8
Questionable Status
Register (QUES)
This bit is set to true when a bit is set in the QUEStion-
able event status register and the corresponding bit in the
QUEStionable status enable register is true.
4
16
Message Available
(MAV)
This bit is set to true when a request is received from the
digital programming interface and the product is ready to
generate the data byte.
5
32
Standard Event Status
Bit Summary (ESB)
This bit is set to true when a bit is set in the event status
register.
6
64
Request Service
(RQS)
This bit is set to true when a bit is set in the service re-
quest enable register and the corresponding bit exists in
the status byte. The SRQ line of the GPIB is set.
Master Status Sum-
mary (MSS)
This bit is set to true when any bit in the status byte reg-
ister is set to 1 and the corresponding bit in the service
request enable register is set to 1.
7
128
Operation Status Reg-
ister (OPER)
This bit is set to true when a bit is set in the OPERation
event status register and the corresponding bit in the OP-
ERation status enable register is set.
8-15
Not Used
Not used
