Re: Streamdevice/asyn Question

[Dirk Zimoch <dirk.zimoch@psi.ch>]

Szalata, Zenon M. wrote:
> Hi Dirk,
> These are text messages.  Here are a few: INVALID COMMAND ENTRY, NUMBER TOO BIG,
> POSITIVE NUMBER REQUIRED, NO PROBE, OVERFLOW, and a handful of other similar messages.  The device sends such messages in response to some command.  The command may expect a reply or it may not.  So, strictly speaking, these are not unsolicited, and yet they are not expected.

In this case, you can use a mbbi record in "I/O Intr" mode with a protocol like 
this:

in "%{INVALID COMMAND ENTRY|NUMBER TOO BIG|POSITIVE NUMBER REQUIRED|...}";

Whenever such a string is received, the mbbi processes and is set to the index 
of the error messages (starting with 0).

Does the device send "OK" when everything is fine? Then you may put "OK" at index 0.

An alternative would be an exception handler like this:

@mismatch {
  in "%(errorRecord.VAL){INVALID COMMAND ENTRY|...}";
}
some_command {
  out "do someting %d";
  in "OK";
}

If the command does not receive "OK", the @mismatch handler can re-parse the 
input and redirect it to an other record. However, if the command does not 
expect any reply, this approach does not work. (You can't have a mismatch on 
nothing.)

Dirk

> Thanks,
> Zen 
>
> -----Original Message-----
> From: Dirk Zimoch [mailto:dirk.zimoch@psi.ch] 
> Sent: Thursday, October 09, 2008 9:04 AM
> To: Szalata, Zenon M.
> Subject: Re: Streamdevice/asyn Question
>
> Hi Zen,
>
> Give some examples of your messages.
>
> Dirk
>
> Szalata, Zenon M. wrote:
> > I am writing a soft ioc for a gpib device using streamdevice with asyn.  The device in question can send an unsolicited text message, which I do not know how to handle.  I tried defining a record with SCAN "I/O Intr" but cannot make it work, mainly I think, because there are a number of such messages possible and they are all different.  Basically, I want to capture the message in a record and display it on an edm screen.
> > The streamdevice manual hints that a record with SCAN "I/O Intr" approach might work.  In the manual there is also a mention of mismatch exception handler.  There aren't enough details for me to know how to implement something that works.
> >
> > Thanks in advance,
> > Zen
>
> --
> Dr. Dirk Zimoch
> Paul Scherrer Institut, WBGB/006
> 5232 Villigen PSI, Switzerland
> Phone +41 56 310 5182

--
Dr. Dirk Zimoch
Paul Scherrer Institut, WBGB/006
5232 Villigen PSI, Switzerland
Phone +41 56 310 5182