RE: stream device - multiple values from a string

[<peter.owens@stfc.ac.uk>]

If you are using an older version of stream device you might have to explicitly specify the .VAL field.


-----Original Message-----
From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of S. Banerian
Sent: 02 July 2015 22:44
To: EPICS Tech Talk
Subject: stream device - multiple values from a string


I'm setting up an IOC to read/write to an RF amp that communicates over the net apropos of stream device.

For single value send/receives, I've not encountered any thing serious.

However, there are a few parameters that we need to read back that come from a single query.

background:
you sent it a string query, it sends back a reply.

what is sent over telnet:

/DEV659/DEMODS/0/SAMPLE: ?

what is received in reply:

/DEV659/DEMODS/0/SAMPLE: TS=2938752.083168305, X=0.0000022024, Y=-0.0000035017, F=25900801.32071, Phi=2.45412 (all on one line, no CR/LF)

With reference to
http://epics.web.psi.ch/software/streamdevice/doc/tipsandtricks.html#readmany
 (part C):

read_AB {out "GET A,B"; in "A=%f, B=%(\$1)f";}

my protocol file has:

readts{
    out "/DEV659/DEMODS/0/SAMPLE: ?";
    in  "/DEV659/DEMODS/0/SAMPLE: TS=%f, X=%(\$1)f, Y=%(\$2)f, F=%(\$3)f, Phi=%(\$4)f"; }

and the db file, with substitution in st.cmd DEVICE=DEMOD

record(ai, "$(DEVICE):ts") {
  field(SCAN, "1 second")
  field(DTYP, "stream")
  field(INP, "@zi.proto
readts($(DEVICE):x,$(DEVICE):y,$(DEVICE):f,$(DEVICE):phi) zi") }

record(ai, "$(DEVICE):x") {
}

record(ai, "$(DEVICE):y") {
}

record(ai, "$(DEVICE):f") {
}

record(ai, "$(DEVICE):phi") {
}


IOC shell startup errors observed:

Field 'DEMOD:x' not found

in format string: "%(DEMOD:x)f, Y=%(DEMOD:y)f, F=%(DEMOD:f)f, Phi=%(DEMOD:phi)f"

in command 'in'

in protocol 'readts'

while compiling protocol 'readts(DEMOD:x,DEMOD:y,DEMOD:f,DEMOD:phi)' for 'DEMOD:ts'

DEMOD:ts: Protocol parse error


I was considering trying to just read in the TS value and then ignore the rest of the line, then try to add in each value and ignore the rest, in sequence, to see if I could find the error.

I have tried changing the protocol file, hard coding in PV names instead of using macros, with db modification appropriate to that, but the iocsh errors were observed.



--
S. Banerian
UW Clinical Cyclotron
UW School of Medicine
206-598-0302
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