Re: StreamDevice with Telnet port

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

Hi Abdalla,

In most cases ExtraInput = Ignore does more bad than good because it 
switches off part of the input checking.

If you get wrong inputs (e.g. "Running" instead of a number) this almost 
always related to protocols that do not consume all input that a command 
produces.

If for example a command sends a long, maybe multi-line string and you 
only parse the beginning until you find an "interesting" value, the 
remainder of the string is still somewhere.

StreamDevice tries to discard such "old input" at the beginning of every 
'out' command, but it is a race condition. If the device sends more 
input as a result of the previous command after the flush, it will be 
received instead of the real reply of the next command. This is also 
true for replies on set commands. If the device sends a reply after your 
sent a set command, you should read it and not "fire and forget" the set 
value. Otherwise the replay may mix with the data of the next command.

Thus first you should remove all the ExtraInput = Ignore.
Then find out which command replies something with "Running" which you 
may not have read. Try to connect with telnet and type the commands 
manually. In the protocol consume *everything* the device sends back.

For more details I need to know more about the device and what commands 
it knows. If possible send a link to the manual. Also your full protocol 
file would be helpful.

Dirk


On 11.03.2018 13:54, Abdalla  Ahmad wrote:
> Hi
>
> We have the Gamma QPC ion-pump controllers controlled via StreamDevice 
> through telnet, port 23. We have 4 parameters implemented, pressure, 
> voltage, current, and channel status. The problem is that the IOC gives 
> an error that the value received for the pressure PV is "Running", i.e. 
> "Input Running does not match format %E". Seems like at some point the 
> controller is not finishing a previous parameter and the IOC receives 
> something different than the current parameter requested.
>
> We have the following in the protocol file:
>
> OutTerminator = CR;
>
> InTerminator = CR;
>
> ReadTimeout = 2000;
>
> ReplyTimeout = 2000;
>
> And each parameter in the protocol file has ExtraInput = Ignore at the 
> end. Any help resolving this mismatching issue?
>
> Best Regards,
>
> Abdalla Ahmad
>
> Control Engineer
>
> SESAME
>
> Allan, Jordan.
>
> Tel: (+962-5) 3511348 , ext. 265
>
> Fax: (+962-5) 3511423
>
> Mob: (+962-7)88183296
>
> www.sesame.org.jo <http://www.sesame.org.jo/>