Rohde & Schwarz SML01, Руководство по эксплуатации

Страница: 170 / 299

Status Reporting System R&S®SML / R&S®SMV03
1090.3123.12 E-6 5.22
Use of Status Reporting System
To make effective use of the status reporting system, the information collected there must be
transferred to the controller and further processed. There are several methods to this effect which are
described in the following. For detailed examples see chapter 7, "Programming Examples").
Service Request, Making Use of Hierarchy Structure
Under certain conditions, the instrument can send a service request (SRQ) to the controller. The service
request normally triggers an interrupt at the controller to which the control program can respond with
corresponding actions. Fig. 5-4 shows that an SRQ is triggered if one or several of the bits 2, 3, 4, 5 and
7 of the status byte are set and enabled in the SRE. Each of these bits combines the information of
another register, the error queue or the output buffer. By setting the ENABle parts of the status registers
accordingly, it is achieved that arbitrary bits of an arbitrary status register trigger an SRQ. To make use
of the possibilities of the service request, all bits of the SRE and ESE enable registers should be set to "1".
Examples (see also Fig. 5-4 and chapter 7, "Programming Examples"):
Use of command
*OPC
to generate an SRQ
Set bit 0 in the ESE (Operation Complete).
Set bit 5 in the SRE (ESB).
The instrument generates an SRQ after completion of its settings.
Indication of end of sweep by means of an SRQ at the controller
Set bit 7 (sum bit of STATus:OPERation register) in SRE.
Set bit 3 (sweeping) in STATus:OPERation:ENABle.
Set bit 3 in STATus:OPERation:NTRansition so that the transition of sweeping bit 3 from 1 to 0
(end of sweep) is recorded in the EVENt part.
The instrument generates an SRQ after completion of a sweep.
The SRQ is the only way for the instrument to become active on its own. Each controller program
should, therefore, set the instrument such that a service request is triggered in the event of a
malfunction. The program should react appropriately to the service request. A detailed example of a
service request routine is included in chapter 7, "Programming Examples".
Serial Poll
In a serial poll, just as with command
*STB
, the status byte of an instrument is queried. However, the
query is implemented by means of interface messages and is therefore clearly faster. The serial-poll
method has already been defined in IEEE 488.1 and used to be the only standard method for different
instruments to query the status byte. The method also works with instruments which do not adhere to
SCPI nor to IEEE 488.2.
The QuickBASIC command for executing a serial poll is
IBRSP()
. Serial polling is mainly used to obtain
a fast overview of the states of several instruments connected to the IEC/IEEE bus.