R&S NRP
Remote Control - Commands
1144.1400.12 6.91
E-3
Parallel Poll
In case of a parallel poll, up to eight devices are simultaneously requested by the controller 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 connected to the
IEC/IEEE bus caused an SRQ. For this purpose, SRE and PPE must be set to the same value.
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 evaluated by the controller program.
Queries are mainly used after an SRQ to obtain detailed information about the cause of the SRQ.
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
Æ
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 registers. 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.
