Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Mon, 30 Sep 2013 11:27:36 -0500

Hi Michael,

On 09/30/2013 10:54 AM, Michael Johnson wrote:

We have a new unix-side process at JLab with some interesting knowledge,
and we want to push this knowledge out to an interface. There will be a
lot of text and long lists - way past the EPICS String record
40-character limit.

Please offer any advice or pointers you have:

1) What EDM widgets are favored for this kind of large text output?

2) How does one push data to EDM when PVs do not fit requirements? File
I/O? IPC?

I believe all EPICS OPIs now support long strings, which are just

character arrays containing text (which in most cases should be

nil-terminated, but the client must not assume that). MEDM and EDM

certainly allow you to point a text widget to a waveform record or other

array field (the aSub record is also good for this) that is configured

to hold CHARs. In the case of MEDM you do have to configure the widget

display Format to "string", I'm not sure about EDM. Note that the

caput/caget/camonitor programs that come with base support long strings

with a -S option.

I can't tell you how the widget actually interprets the text, hopefully

EDM supports wrapping and line breaks, but I have no idea if it actually

does (I don't think MEDM can but I haven't tried it). It would seem

like someone might even be able to write a widget that could handle a

pluggable formatter to accept Markdown or even HTML, but I'm not sure if

it would really be worth doing that.

HTH,

- Andrew
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System