Rohde & Schwarz NRT 1080.9506.02/.62, Руководство по эксплуатации

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NRT Status Reporting System
1080.9506.02 3.57 E-6
3.7.4.2 Serial Poll
In a serial poll, just as upon the command "
*STB
", the status byte of an instrument is queried. However,
the query is made via interface messages and is thus clearly faster. The serial-poll method has already
been defined in IEEE 488.1 and used to be the only standard possibility 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 quick-BASIC command for executing a serial poll is "
IBRSP()
". The serial poll is mainly used to
obtain a fast overview of the state of several instruments connected to the IEC bus.
3.7.4.3 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 a logic "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, considering bit 6 – AND as well. The results are ORed, the result is then sent (possibly
inverted) as a response to the parallel poll of the controller. The result can also be queried without par-
allel poll by means of the command "
*IST
".
The instrument first has to be set for the parallel poll using the 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 for a parallel poll can be found in 'Annex D,
"Programming Examples".
3.7.4.4 Query by Means of Commands
Each part of any status register can be read by means of queries. The individual commands are listed in
the detailed description of the registers in Section 3.7.3. 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.
3.7.4.5 Error Queue Query
Each error state in the instrument leads to an entry in the error queue. These entries are detailed
plain-text error messages. If a sensor is connected, the errors concerning this sensor can be accessed
in manual control via the UTIL – TEST – SENS menu. In general, the error queue is queried via the IEC
bus using the command "
SYSTem:ERRor?
". Each call of "
SYSTem:ERRor?
" provides one 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.
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