Remote Control - Fundamentals R&S
NRP
1144.1400.12 5.4
E-3
Communication on Data Lines
The IEC/IEEE bus is the most common remote interface for measuring devices. It has also been
implemented in the R&S NRP. The remote controller and the R&S NRP communicate by means of
messages. The messages sent on the data lines (
Æ
section "
Interfaces
", page
6.124
) can be divided
into two groups:
•
Interface messages
•
Device-dependent messages
Interface Messages
Interface messages are transmitted on the data lines of the IEC/IEEE bus when the ATN control line is
active. Interface messages allow the controller and the device to communicate and can only be sent by
a controller which serves as the IEC/IEEE-bus controller. Interface commands can be further classified
as
•
common commands
•
addressed commands
Common commands affect all devices connected to the IEC/IEEE bus without requiring an address,
whereas addressed commands only affect devices addressed as a listener. The interface messages
relevant for the device are described in the annex
Æ
"
Interface Messages
", page
6.127
.
Device-Dependent Messages (Commands and Responses)
Device-dependent messages are transmitted on the data lines of the IEC/IEEE bus when the ATN
control line is not active. The ASCII code is used. Device-dependent messages are classified
according to the direction in which they are sent:
Commands
are messages sent by the controller to the R&S NRP. They control the device functions and request
information. The commands are classified
according to the effect they have on the device:
Setting commands
trigger device settings, e.g. an device reset or a configuration of
the trigger system.
Queries
cause device data to be provided in the output queue, where they
can be fetched via the IEC/IEEE bus. Queries are available for
most of the setting commands. They are obtained by adding a
question mark to the setting command.
