Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Thu, 9 Jul 2020 15:41:28 -0700

I've recalled some more details from my encounter with this device.

On 7/8/20 6:38 AM, Hu, Yong via Tech-talk wrote:
> ReadData {
>          out "DCV  10, 1E-6";
>          in "%f";
> }

The "DCV" command is the measurement range setup command.
By itself, this command does not a measurement will be
made.  It also may have side effects.

In particular, this device has a peculiar idea of "AUTO"
trigger mode (which is the default).  In this mode,
a GPIB read when the device input buffer is empty will
return the most recent measurement.

I found that this hard to follow (at least mentally,
if not with stream device) as command which are documented
as having no reply on success actually seem to.

The commands I used, both for the IOC I linked yesterday are:

> setup {
>     out "TARM HOLD;TRIG SYN;NRDGS 1,AUTO";
> }
> 
> # restore auto trigger
> detach {
>     out "TARM AUTO;TRIG AUTO;NRDGS 1,AUTO";
> }
> 
> sample {
>     out "TARM SGL";
>     in "%f";
> }

The associated database has the idea of attached (IOC control)
and detached (front panel control).  My application was
supporting a benchtop setup, and those involved were
comfortable with setting up modes and ranges in this way.

"TARM HOLD" is disabling triggering.  "TRIG SYN" is setting up
for single trigger.  "NRDGS 1,AUTO" is number of readings to
average (something like sampling period).

When in attached mode, the "sample" exchange is performed
periodically.  "TARM SGL" triggers a single acquisition,
and waits for a single result.

The detach action is putting things back to free running
trigger for front panel operation.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System