Command Reference
R&S
®
ZNL/ZNLE
577
User Manual 1178.5966.02 ─ 07
●
Service request (SRQ) initiated by the measuring device
●
Serial poll of all devices in the bus system, initiated by the controller to find out who
sent a SRQ and why
●
Parallel poll of all devices
●
Query of a specific instrument status by means of commands
●
Query of the error queue
Service Request
The R&S
ZNL/ZNLE can send a service request (SRQ) to the controller. Usually this
service request causes an interrupt, to which the control program can react appropri-
ately.
Initiating an SRQ
As shown in section
, an SRQ is initiated if one or several
of bits 2, 3, 4, 5 or 7 of the status byte are set and enabled in the SRE. Each of these
bits summarizes the information of a further register, the error queue or the output buf-
fer.
The ENABle parts of the status registers can be set such that arbitrary bits in an arbi-
trary status register initiate an SRQ. To use the possibilities of the service request
effectively, all bits in the enable registers SRE and ESE should be set to "1".
Example: Use *OPC to generate an SRQ
1. Set bit 0 in the ESE (Operation Complete).
2. Set bit 5 in the SRE (ESB).
3. Insert
*OPC
in the command sequence (e.g. at the end of a sweep)
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
ZNL/ZNLE 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.
VNA Remote Control Basics
www.allice.de
Allice Messtechnik GmbH
