R&S NRP2 - Page 190

Remote Control Fundamentals
R&S
®
NRP2
172User Manual 1173.9157.02 ─ 03
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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 instrument are described in chapter A.1.5,
"Interface messages", on page 351.
5.6.2 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:
5.6.2.1 Commands
Commands are messages sent by the controller to the R&S NRP2. They control the
device functions and request information. The commands are classified
according to the effect they have on the device:
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Setting commands
trigger device settings, e.g. an device reset or a configuration of the trigger system.
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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.
according to their definition in the IEEE 488.2 and SCPI 1999.0 standard:
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Common commands
are precisely defined in the IEEE 488.2 standard in terms of function and notation.
They relate to functions such as the management of standardized status registers,
resetting and self test.
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Device-specific commands
relate to functions that depend on device characteristics such as the frequency set-
ting. Many of these commands are also standardized by the SCPI Consortium (
chapter 5.7.1, "SCPI Standard", on page 173). The standard allows device-specific
extensions of commands.
Parallelism
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Overlapping commands
can be executed while another command is being executed.
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Sequential commands
can only be executed when the execution of all other commands is completed.
In the R&S NRP2, only the remote control commands INIT:IMM and CAL:ZERO:AUTO
ONCE can overlap with other commands.
Communication on Data Lines