Reference Information for Remote Control
R&S
®
SMA100B
517
User Manual 1178.3834.02 ─ 03
●
Truth values (Boolean values) are returned as
0
(for OFF) and
1
(for ON).
Example:
Setting command:
HCOPy:DEV:COL ON
Query:
HCOPy:DEV:COL?
Response:
1
●
Text (character data) is returned in a short form.
Example:
Setting command:
HCOPy:PAGE:ORIentation LANDscape
Query:
HCOP:PAGE:ORI?
Response:
LAND
●
Invalid numerical results
In some cases, particularly when a result consists of multiple numeric values, inva-
lid values are returned as 9.91E37 (not a number).
A.1.4 Command Sequence and Synchronization
IEEE 488.2 defines a distinction between overlapped and sequential commands:
●
A sequential command always completes executing before the next command
starts. Commands that are processed quickly are defined as sequential com-
mands. They are not implemented in the instrument. However, the execution time
of most of the commands is so short that they act as sequential commands, if they
are sent in separate command lines.
●
An overlapping command is still running when the next command starts. Usually,
an overlapping command takes a certain time to process its task, and thus allows
the program to execute other tasks, while it is still running. If overlapping com-
mands have to follow a specific order, for example to avoid incorrect measurement
readings, they must be executed in sequence. This is called synchronization
between the controller and the instrument.
Several setting commands within a command line are not necessarily processed in the
order they are received. Even if they are implemented as sequential commands. To fol-
low a particular sequence, send each command in a separate line.
As a rule, send commands and queries in different program messages.
A.1.4.1
Preventing Overlapping Execution
To prevent an overlapping execution of commands, one of the commands
*OPC
,
*OPC?
or
*WAI
can be used. All three commands cause a certain action only to be
carried out after the hardware has been set. The controller can be forced to wait for the
corresponding action to occur.
Additional Basics on Remote Control
