Remote Control - Commands
R&S
®
NRP2
313User Manual 1173.9157.02 ─ 03
6.13.20.2 Serial Poll
Like the *STB? command, the serial poll is used to query the status byte of a device.
Querying is implemented by interface messages, however, and is therefore much
quicker. The serial poll method has already been defined in the IEEE 488.1 standard,
and used to be the only standard method of querying the Status Byte Register. This
method also works with devices that conform neither to SCPI nor to IEEE 488.2. Serial
poll is mainly used to obtain a quick overview of the device status of several devices
connected to the IEC/IEEE bus.
6.13.20.3 Parallel Poll
In case of a parallel poll, up to eight devices are simultaneously requested by the con-
troller to transmit one bit of information on the data line, i.e. to set the data line assigned
to each device to logical 0 or 1. Analogously to the SRE register, which determines the
conditions for generating an SRQ, a Parallel Poll Enable Register (PPE) is available
which is ANDed bit-by-bit with the STB (taking into account bit 6). The results are ORed
and the result is then sent (possibly in inverted format) to the controller as a response to
a parallel poll. The result can also be read without a parallel poll by the query *IST?.
The parallel poll mode is mainly used to quickly find out which of the many devices con-
nected to the IEC/IEEE bus caused an SRQ. For this purpose, SRE and PPE must be
set to the same value.
6.13.20.4 Queries
Each part of a status register can be read out by queries. The queries are specified in
the description of the SCPI commands (command system STATus). The queries always
yield a number representing the bit pattern of the queried register. This number is eval-
uated by the controller program.
Queries are mainly used after an SRQ to obtain detailed information about the cause of
the SRQ.
6.13.20.5 Error Queue Query
Each error in the device causes an entry in the error queue. The entries in the error queue
are error messages in plain text. If a sensor is connected, sensor-specific errors can be
seen via manual control in the menu File(Error List or in remote control via "Error List...".
Usually, the error queue is read with the SCPI query SYSTem:ERRor?. Each
SYSTem:ERRor? query is answered by an entry from the error queue. If there are no
more error messages in the error queue, 0 = "No error" is returned by the device.
The error queue should be queried in the controller program after each SRQ since the
queue entries provide a more precise description of the error cause than the status reg-
isters. In particular, in the test phase of a controller program the error queue should be
queried at regular intervals since it also registers faulty commands from the controller to
the device.
STATus
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