R&S FSMR, Operating Manual

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R&S FSMR Status Reporting System
1166.3363.12 5.33 E-1
Parallel Poll
In a parallel poll, up to eight instruments are simultaneously requested by the controller by means of a
single command to transmit 1 bit of information each on the data lines, i.e., to set the data line allocated
to each instrument to logically "0" or "1". By analogy to the SRE register which determines under which
conditions an SRQ is generated, there is a parallel poll enable register (PPE) which is ANDed with the
STB bit by bit as well considering bit 6. The results are ORed, the result is then sent (possibly inverted)
as a response in the parallel poll of the controller. The result can also be queried without parallel poll by
means of command "*IST".
The instrument first has to be set for the parallel poll using quick-BASIC command "IBPPC()". This
command allocates a data line to the instrument and determines whether the response is to be inverted.
The parallel poll itself is executed using "IBRPP()".
The parallel-poll method is mainly used in order to quickly find out after an SRQ which instrument has
sent the service request if there are many instruments connected to the IEC bus. To this effect, SRE
and PPE must be set to the same value. A detailed example as to the parallel poll is to be found in
chapter 7, Program Examples.
Query by Means of Commands
Each part of every status register can be read by means of queries. The individual commands are
indicated in the detailed description of the registers in Section 3.8.3. What is returned is always a
number which represents the bit pattern of the register queried. Evaluating this number is effected by
the controller program.
Queries are usually used after an SRQ in order to obtain more detailed information on the cause of the
SRQ.
Error-Queue Query
Each error state in the instrument leads to an entry in the error queue. The entries of the error queue
are detailed plain-text error messages which can be looked at in the ERROR menu via manual control
or queried via the IEC bus using command "SYSTem:ERRor?". Each call of "SYSTem:ERRor?"
provides an entry from the error queue. If no error messages are stored there any more, the instrument
responds with 0, "No error".
The error queue should be queried after every SRQ in the controller program as the entries describe the
cause of an error more precisely than the status registers. Especially in the test phase of a controller
program the error queue should be queried regularly since faulty commands from the controller to the
instrument are recorded there as well.