R&S SMB Interface and Device Messages
1407.0806.32 5.9 E-2
Interface and Device Messages
The messages transferred via the data lines of the IEC/IEEE-bus (see Section "IEC/IEEE Bus
Interface") or via a TCP/IP network can be divided into two groups:
– interface messages and
– device messages.
Interface Messages
Interface messages are transferred on the data lines of the IEC/IEEE bus, the ATN control line being
active. They are used for communication between controller and instrument and can only be sent by a
computer which has the function of an IEC/IEEE bus controller.
Interface commands can be further subdivided into
- universal commands
- addressed commands
Universal commands act on all devices connected to the IEC/IEEE-bus without previous addressing,
addressed commands only act on devices previously addressed as listeners. The interface messages
relevant to the instrument are listed in Section "IEC/IEEE Bus Messages".
If an Ethernet connection is present, signalling via a hardware control line is not required. The
IEC/IEEE-bus interface commands are emulated (see "IEC/IEEE Bus Messages").
Device Messages (Commands and Device Responses)
Device messages are transferred on the data lines of the IEC/IEEE-bus, the "ATN" control line not
being active. ASCII character set is used.
If an Ethernet connection is present, signalling via a hardware control line is not required.
The device messages are equal for the different interfaces (IEC/IEEE bus and Ethernet). A distinction is
made according to the direction in which they are sent:
Commands
(Program
Messages)
are messages the controller sends to the instrument. They operate the device
functions and request information.
The commands are subdivided according to two criteria:
1. According to the effect they have on the instrument:
Setting commands
cause instrument settings such as a reset of the instrument
or setting the frequency.
Queries
cause data to be provided for output on the IEC/IEEE bus,
e.g. for identification of the device or polling a parameter
value. Queries are formed by directly appending a question
mark to the header.
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