Remote Control
R&S
®
CMW500
165
User Manual 1173.9463.02 ─ 02
during command recognition and execution. The receipt of a
DCL
clears the input buffer
and immediately initiates a message to the command recognition.
6.5.2 Command Recognition
The command recognition stage analyzes the data received from the input unit. It pro-
ceeds in the order in which it receives the data. Only a
DCL
is serviced with priority, e.g.
a
GET
(Group Execute Trigger) is only executed after the commands received before.
Each recognized command is immediately transferred to the data set but not executed
immediately.
The command recognition detects syntax errors in the commands and transfers them to
the status reporting system. The rest of a command line after a syntax error is still exe-
cuted, if possible. After the syntax check, the range of the numerical parameters is
checked, if required.
If the command recognition detects a delimiter or a
DCL
, it also requests the data set to
perform the necessary instrument hardware settings. Subsequently it is immediately pre-
pared to process further commands. This means that new commands can already be
serviced while the hardware is still being set ("overlapping execution").
6.5.3 Data Base and Instrument Hardware
The expression "instrument hardware" denotes the part of the instrument fulfilling the
actual instrument function - signal generation, measurement etc. The controller is not
included. The data base manages all the parameters and associated settings required
for the instrument hardware.
Setting commands lead to an alteration in the data set. The data set management enters
the new values (e.g. frequency) into the data set, however, it only passes them on to the
hardware when requested by the command recognition. This can only occur at the end
of a command line, therefore the order of the setting commands in the command line is
not relevant.
The commands are only checked for their compatibility among each other and with the
instrument hardware immediately before they are transmitted to the instrument hardware.
If the instrument detects that execution is not possible, an "execution error" is signaled
to the status reporting system. All alterations of the data set are canceled, the instrument
hardware is not reset. Due to the delayed checking and hardware setting, however,
impermissible instrument states can be set for a short period of time within one command
line without this leading to an error message (example: simultaneous routing of the same
generator signal to different output connectors). At the end of the command line, however,
a permissible instrument state must have been reached again.
Before passing on the data to the hardware, the settling bit in the
STATus:OPERation
register is set (cf. section
). The hardware executes the settings and
resets the bit again as soon as the new state has settled. This fact can be used to syn-
chronize command servicing.
Queries induce the data set management to send the desired data to the output unit.
Command Processing
