SRS Labs SR430, Manual

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80
Remote Programming
DCSL 0<lf> Set discriminator slope to
positive
DCLV 10E-3 <lf> Set the discriminator level
to 10 mV (10E-3 Volts)
*IDN? <lf> Queries the device
identification
SSCN <lf> Starts data acquisition
(same as [START] key)
RSCN? <lf> Queries the number of
records per scan
INTERFACE READY AND STATUS
The Interface Ready bit in the Serial Poll Status
Byte signals that the SR430 is ready to receive
and execute a command. When a command is re-
ceived, this bit is cleared indicating that an opera-
tion is in progress. While the operation is in
progress, no other commands will be processed.
Commands received during this time are stored in
a buffer to be processed later. Only GPIB serial
polling will generate a response while a command
is in progress. When the command execution ter-
minates, the Interface Ready bit is set again and
new commands will be processed. Since most
commands execute very quickly, the host comput-
er does not need to continually check the Interface
Ready bit. Commands may be sent one after an-
other and they will be processed immediately.
However, some commands, such as file com-
mands and math operations, may require a long
time to execute. In addition, the host program may
need to check that these operations executed
without error. In these cases, after the command is
sent, the Status Bytes should be queried.
When using the GPIB interface, serial polling may
be used to check Interface Ready bit in the Serial
Poll Byte while an operation is in progress. After
the Interface Ready bit becomes set, signalling the
completion of the command, then the ERR bit may
be checked to verify successful completion of the
command.
If the RS232 interface is used, or serial polling is
not available, then the *STB?, *ESR?, ERRS?,
and MCSS? status query commands may be used
to query the Status Bytes. Since the SR430 pro-
cesses one command at a time, the status query
will not be processed until the previous operation
is finished. Thus a response to the status query in
itself signals that the previous command is fin-
ished. The query response may then be checked
for various errors.
For example, the command line SVTR;ERRS?
<lf> will save the data to disk and return the Error
Status Byte when finished. The Disk Error bit may
be checked to make sure that the Save Trace
command terminated without error. Since the
Save Trace command may take a long time to ex-
ecute, it is important that the host computer inter-
face does not time out while waiting for the re-
sponse to the ERRS? query. In the case where
the host interface times out before the ERRS? re-
sponse, the host program must wait before send-
ing the ERRS? query.