Re: stream device driver parse question

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

Florian Feldbauer wrote:
> Hi,
>
> you can use the redirection mechanism of streamdevice.
> Just configure your ai1 record to use stream as DTYP and the protocol as 
> input:
>
> record (ai "ai1") {
>     field (DTYP, "stream")
>     field (INP,  "@myDev.proto getMsg dev1")
>     field (SCAN, "I/O Intr")
>  }
>
>
> Your protocol would look like this:
> getMsg {
>   in "*05CC%d#*05DD%(ai2.VAL)d#*05EE%(ai3.VAL)#"
> }

There is a "d" missing near the end ;-). But otherwise I would do the 
same: in "*05CC%d#*05DD%(ai2.VAL)d#*05EE%(ai3.VAL)d#";

Keep in mind that with redirection, the other two records ai2 an ai3 are 
processed by ai1. Thus do not set SCAN, DTYP or INP for them. Except if 
you want to scale the values from integer to floating point. Then 
redirect to .RVAL instead and use DTYP="Raw Soft Channel" and 
LINR="Linear" in those records and set ESLO according to your needs.

If you need to FLNK from these record to anything else, put the FLNK 
into ai1, because it will finish processing last and then all three 
records are guaranteed to have values.

The other alternative is not to use redirection and make all three 
records "I/O Intr". Then each record would use read its part of the 
message (in no particular order) and ignore the other values (with %*):

getData1 { in "*05CC%d#*05DD%*d#*05EE%*d#"; }
getData2 { in "*05CC%*d#*05DD%d#*05EE%*d#"; }
getData3 { in "*05CC%*d#*05DD%*d#*05EE%d#"; }

BTW, with "I/O Intr", StreamDevice has to poll for new input. Make sure 
that PollPeriod is short enough in order not to have a too long delay 
between the message and processing the record. The default value for 
PollPeriod is ReplyTimeout and the default value for ReplyTimeout is 1 
second. I usually choose approximately 1/10 of the expected send period 
of the device. A too short PollPeriod wastes CPU time.

Dirk

> I'm not sure though if one should define the length for the format 
> converters here?

Why? There is a # after the number that terminates the %d converter.

> Best regards,
> Florian
>
> Am 17.05.2012 07:15, schrieb Silver:
> > hi, all:
> >
> >    If the device send a string to IOC automaticlly, the data is like 
> > "*05CC1234#*05DD5678#*05EE1345#". I have three ai records as ai1,ai2,ai3.
> > I want to get "1234" of "*05CC1234#" to ai1, "5678" of "*05DD5678#" to 
> > ai2, "1345" of "*05EE1345#" to ai3, how can I implement it?
> >    thanks a lot in advance.
> >
> >
> > Best regards
> > Geyang  2012-05-17