RE: Long string command to device

[Mark Rivers <rivers@cars.uchicago.edu>]

Hi Bo,

The waveform record can be used for both input and output.

This is from the documentation for StreamDevice for the waveform record:

************************
If FTVL=="CHAR" or FTVL="UCHAR":
    In this case, the complete waveform is treated as a large single string of size NORD. No separators are printed or expected.
    Output: x=range(VAL,0,NORD)
       The first NORD characters are printed, which might be less than NELM.
    Input: VAL=x, NORD=length(x)
        A maximum of NELM-1 characters can be read. NORD is updated to the index of the first of the trailing zeros. Usually, this is the same as the string length.
************************

Mark

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__________________________________
From: tech-talk-bounces@aps.anl.gov [tech-talk-bounces@aps.anl.gov] on behalf of Bo Jakobsen [lister@f77.dk]
Sent: Tuesday, September 20, 2016 3:34 AM
To: tech-talk@aps.anl.gov
Subject: Long string command to device

Hi,

I am working on modifying an EPICS interface for a LakeShore 336 (LS336)
temperature controller.
In that connection I need to send strings to the LS336 which extends 40
characters.

I found the following thread:
http://www.aps.anl.gov/epics/tech-talk/2016/msg00887.php
which discusses a similar problem, and suggests to use waveform records
and StreamDevice (which I am already using).

However, I am unable to get this to work.
As I read the documentation of waveform records they are only for input,
and hence does not allow to set the OUT field (I am using EPICS 3.14)

Can anyone help with a solution to this problem?

Best
Bo Jakobsen