Remote Control
R&S
®
ZNA
747
User Manual 1178.6462.02 ─ 12
As soon as all commands preceding
*OPC
have been completed, the instrument gen-
erates an SRQ.
Example: Generate an SRQ when a limit is exceeded
1. Set bit 3 in the SRE (summary bit of the
STATus:QUEStionable
register, set
after
STATus:PRESet
)
2. Set bit 10 in the
STATus:QUEStionable:ENABle
register (summary bit of the
STATus:QUEStionable:LIMit1
register)
3. Set bit 1 in the
STATus:QUEStionable:LIMit1:ENABle
register
The R&S
ZNA generates an SRQ when the event associated with bit 1 of the
STATus:QUEStionable:LIMit1:ENABle
register occurs, i.e. when any point on
the first trace fails the limit check.
Example: Find out which event caused an SRQ
The procedure to find out which event caused an SRQ is analogous the procedure to
generate an SRQ:
1.
STB?
(query the contents of the status byte in decimal form)
If bit 3 (QUEStionable summary bit) is set, then:
2.
STAT:QUES:EVENT?
(query STATus:QUEStionable register)
If bit 10 (QUEStionable:LIMit1 summary bit) is set, then:
3. Query
STAT:QUES:LIMit1:EVENT?
(query
STATus:QUEStionable:LIMit1
register)
If bit 1 is set, then the first trace failed the limit check.
The SRQ is the only possibility for the instrument to become active on its own. Each
controller program should set the instrument such that a service request is initiated in
the case of malfunction. The program should react appropriately to the service request.
7.5.4.2
Serial Poll
In a serial poll, the controller queries the STatus Bytes of the devices in the bus system
one after another. The query is made via interface messages, so it is faster than a poll
by means of
*STB?
.
The serial poll method is defined in IEEE 488.1 and used to be the only standard pos-
sibility for different instruments to poll the status byte. The method also works for
instruments which do not adhere to SCPI or IEEE 488.2.
The serial poll is mainly used to obtain a fast overview of the state of several instru-
ments connected to the controller.
Status Reporting System
