Rohde & Schwarz SMU200A - GPIB Interface (IEC;IEEE Bus Interface)

Remote Control Basics
R&S
®
SMU200A
453Operating Manual 1007.9845.32 ─ 15
Command Long term Effect on the instrument
&GTL Go to Local Transition to the "local" state (manual control).
&GTR Go to Remote Transition to the "remote" state (remote control).
&GET Group Execute Trigger Triggers a previously active instrument function (e.g. a
sweep). The effect of the command is the same as with that
of a pulse at the external trigger signal input.
&LLO Local Lockout Disables switchover from remote control to manual control
by means of the front panel keys.
&NREN Not Remote Enable Enables switchover from remote control to manual opera-
tion by means of the front panel keys
&POL Serial Poll Starts a serial poll.
6.1.4 GPIB Interface (IEC/IEEE Bus Interface)
To be able to control the instrument via the GPIB bus, the instrument and the controller
must be linked by a GPIB bus cable. A GPIB bus card, the card drivers and the program
libraries for the programming language used must be provided in the controller. The con-
troller must address the instrument with the GPIB bus address (see chapter 6.1.4.2,
"GPIB Instrument Address", on page 454).
Characteristics
The GPIB interface is described by the following characteristics:
●
Up to 15 instruments can be connected
●
The total cable length is restricted to a maximum of 15 m; the cable length between
two instruments should not exceed 2m.
●
A wired "OR"-connection is used if several instruments are connected in parallel,
since the slowest instrument determines the speed.
6.1.4.1 GPIB Interface Messages
Interface messages are transmitted to the instrument on the data lines, with the attention
line (ATN) being active (LOW). They are used for communication between the controller
and the instrument and can only be sent by a computer which has the function of a GPIB
bus controller. GPIB interface messages can be further subdivided into:
●
Universal commands: act on all instruments connected to the GPIB bus without
previous addressing
●
Addressed commands: only act on instruments previously addressed as listeners
Universal Commands
Universal commands are encoded in the range 10 through 1F hex. They affect all instru-
ments connected to the bus and do not require addressing.
Remote Control Interfaces and Protocols