Experimental Physics and
Industrial Control System

"Zhang, Dehong" <[email protected]> · Tue, 27 Aug 2013 16:51:24 -0700

Hi Dirk and Wesley,

Thank you very much for your helps!

I was not very sure whether I could, and how to, use the "$" anchor.  Your suggestions
made me try again -- it works!  Now my protocol is like:

STATUS  { ReplyTimeout = 50; ReadTimeout = 10; InTerminator =; in "%.1/BOS([0-9,P=\-]*EOS)\r\n$/"; }

Because I have
InTerminator =;
streamdevice will not remove the "\r\n".  The end of my string is really "EOS\r\n".

Thank you again, best regards,
Dehong

________________________________________
From: Dirk Zimoch [[email protected]]
Sent: Friday, August 23, 2013 7:11 AM
To: Zhang, Dehong
Cc: [email protected]
Subject: Re: streamdevice to find the last match

Dehong,

I am not sure if the payload data is the first number or the P= number
or both.

In any case with a %*/.*BOS*/ you should be able to find the last BOS in
your input. After that start reading your data. If P= is your data it
would look like this:

in "%*/.*BOS/*d,P=%dEOS\r\n";

BTW: ExtraInput = Ignore is almost always a bad idea. Use it only if
absolutely necessary.

Dirk

On 23.08.2013 09:55, Dirk Zimoch wrote:
> Hello Dehong,
>
> Is your record "I/O Intr"? I assume so because your STATUS protocol does
> not have any out command.
>
> In that case and if you set InTerminator = CR LF, you should actually
> get 2 messages and the record should be processed twice. Thus at the
> end, your record will have the correct value.
>
> Skipping intermediate results is tricky on the protocol level, because
> how should StreamDevice know that no more input is about to come? What
> if the gap between the messages is sometimes so big, that you actually
> get 2 messages?
>
> But In case you really always get a double message as below and want to
> read the second value only you can skip the first one:
>
> in "BOS%*d,P=%*dEOS\r\nBOS%d,P=%(otherrecord)dEOS\r\n"
>
> In case you may have an arbitrary number of messages connected and
> always want to skip all but the last, things become tricky. I have to
> make up a PCRE. The idea is to do a greedy search for everything up to
> "BOS" and then read the data. I will send you the PCRE later.
>
> Dirk
>
>
>
> On 22.08.2013 21:17, Zhang, Dehong wrote:
>> Hi Dirk and Friends,
>>
>> (Sorry if you get this 2 times. I had a wrong address with my previous
>> send)
>>
>> I run into 2 little problems: I wait for the hardware to send a
>> message like
>> "BOS123456,P=987654EOS\r\n".
>> Here BOS is my starting label and EOS the ending label.
>>
>> Due to timing, which I cannot control, sometimes I would receive 2
>> messages
>> together, like:
>> "BOS123456,P=987654EOS\r\nBOS345,P=987649EOS\r\n".
>> Here the first one was sent when the state was still changing, the
>> second one
>> was sent when the state stablizes. But the time in between is so short
>> that the
>> 2 messages just come out as one. How can I skip the first match, only
>> get the
>> second/last match?
>>
>> My protocal is like:
>> InTerminator = CR;
>> OutTerminator = CR LF;
>> ReplyTimeout = 800;
>> ReadTimeout = 100;
>> WriteTimeout = 100;
>> ExtraInput = Ignore;
>>
>> # Reports from the controller
>> STATUS { ReplyTimeout = 50; ReadTimeout = 10; InTerminator =; in
>> "%.1/BOS([0-9,P=]*EOS)/"; }
>>
>> I tried to use the "$" anchor, but cannot get it to work -- maybe
>> because "$" is a special
>> character in streamdevice.
>>
>> Related to this, sometimes the time in between is not so short that
>> the 2 messages
>> do come out separately, but the time in between is short enough so
>> that my stringin
>> record misses the second message. How can I avoid this? Tune the
>> ReplyTimeout,
>> ReadTimeout and InTerminator?
>>
>> Thank you for your advice. Best regards,
>> Dehong
>>
>
>

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System