Operating instructions

R&S ESCI Messages
1166.6004.12 5.7 E-1
Messages
The messages transferred via the data lines of the IEC bus (see Chapter 8, IEC/IEEE-Bus Interface)
can be divided into two groups:
– interface messages and
– device messages.
IEC/IEEE-Bus Interface Messages
Interface messages are transferred on the data lines of the IEC bus, the "ATN" control line being active.
They are used for communication between controller and instrument and can only be sent by a
controller which has the IEC/IEEE bus control. Interface commands can be subdivided into
– universal commands and
– 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 Chapter 8, IEC/IEEE-Bus Interface – Interface Functions.
Device Messages (Commands and Device Responses)
Device messages are transferred on the data lines of the IEC bus, the "ATN" control line not being
active. ASCII code is used.
A distinction is made according to the direction in which they are sent on the IEC/IEEE bus:
– Commands are messages the controller sends to the instrument. They operate the device
functions and request informations.
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 reset of the
instrument or setting the center frequency.
Queries cause data to be provided for output on the IEC/IEEE
bus, e.g. for identification of the device or polling the
marker.
2. According to their definition in standard IEEE 488.2:
Common Commands are exactly defined as to their function and
notation in standard IEEE 488.2. They refer to
functions such as management of the standar-dized
status registers, reset and selftest.
Device-specific
commands refer to functions depending on the features of the
instrument such as frequency setting. A majority of
these commands has also been standardized by the
SCPI committee (cf. Section "SCPI Introduction")).
– Device responses are messages the instrument sends to the controller after a query. They can
contain measurement results, instrument settings and information on the
instrument status (cf. Section "Responses to Queries").
Structure and syntax of the device messages are described in the following Section.