Re: StreamDevice reading waveforms

[Davide Marcato <davide.marcato@lnl.infn.it>]

I had a similar problem, I think that you can't parse two integers on the same line (the 'in' field of the protocol file), but I'm not sure, maybe someone more expert can explain.. 

I solved parsing the whole line as a string and then I converted it into two integers. Maybe you already know, but pay attention not to parse the separator "\n" as part of that string because because otherwise the waveform is not able to recognize it as the separator.

Davide

On 09/04/2015 23:01, Anthony Pietryla wrote:

I have a device which uses SCPI protocol and returns sets of waveforms in columns where I can request how many rows to return. For instance I can query the device for 3 values of position data and it will return 2 columns (X & Y) and 3 rows. I want to read the columns into separate waveform records. I am having problems with the protocol file for which I need help.

The database records and the protocol file are listed below. When I process the record only the first values (first row of data) are written to each record. With asyn debugging turned on the console shows all three sets of data:

epics> 2015/04/09 13:52:36.877 L0 wrote
TBT_XY 3

2015/04/09 13:52:36.878 L0 read
  2000   6000
  7143   4286
  4286   1429

caget shows only the first value stored:

caget -# 5 B:Spark:TBT_Horizontal

B:Spark:TBT_Horizontal 5 3333 0 0 0 0

caget -# 5 B:Spark:TBT_Vertical

B:Spark:TBT_Vertical 5 -1111 -3333 0 0 0

*******************

The protocol file has:

getTBT_XY {
   Separator = "\n";
   out "TBT_XY 3";
   in   " %(\$1TBT_Horizontal)d %(\$1TBT_Vertical)d";
   ExtraInput = Ignore;
}

**************

The database records are:

record(waveform, "$(P)$(R)TBT_Horizontal")
{
   field(DESC, "TBT Horizontal")
   field(DTYP, "stream")
   field(INP,  "@spark.proto getTBT_XY($(P)$(R)) $(PORT)")
   field(NELM, "262144")
   field(EGU,  "um")
   field(FTVL, "LONG")
}

record(waveform, "$(P)$(R)TBT_Vertical")
{
   field(DESC, "TBT Vertical")
   field(DTYP, "Soft Channel")
   field(NELM, "262144")
   field(EGU,  "um")
   field(FTVL, "LONG")
}

********************

When I comment out the “ExtraInput = Ignore;” line in the protocol file I get error messages:

2015/04/09 15:53:58.170 L0 wrote
TBT_XY 3

2015/04/09 15:53:58.170 L0 asynOctetBase interrupt
2015/04/09 15:53:58.171 L0 read
  3333  -1111
 -3333  -5556
 -2000      0

2015/04/09 15:53:58.271 L0 B:Spark:TBT_Horizontal: 29 bytes surplus input "<0a> -3333  -5556<0a> -200..."
2015/04/09 15:53:58.271 L0 B:Spark:TBT_Horizontal: after 13 bytes: "  3333  -1111"

caget -# 5 B:Spark:TBT_Horizontal

B:Spark:TBT_Horizontal 5 3333 0 0 0 0

caget -# 5 B:Spark:TBT_Vertical

B:Spark:TBT_Vertical 5 -1111 -3333 0 0 0

--
Anthony Pietryla
Principal Controls Engineer
Advanced Photon Source
Argonne National Laboratory

Phone: 630-252-7430
Fax: 630-252-6123

-- 
Davide Marcato
INFN - Laboratori Nazionali di Legnaro
Viale dell'Universita', 2
35020 LEGNARO (PD) - ITALY
Phone: +39 0498068454