Experimental Physics and
Industrial Control System

Ben Franksen <[email protected]> · Thu, 16 Sep 2010 18:34:47 +0200

On Donnerstag, 16. September 2010, Ralph Lange wrote:
> On 12.09.2010 10:23, Ben Franksen wrote:
> > On Sonntag, 12. September 2010, Xu, Chengcheng wrote:
> >> I am trying to test out the EPICS record's new DBE property.
> >
> > You mean the new CA event type called DBE_PROPERTY?
> >
> > To summarize: this nice new feature is not yet fully implemented
> > for all record types; also, camonitor misses an option to specify
> > the request type to make this useful. I tried to add it but it
> > doesn't work.
>
> Are you sure?
>
>  > ./bin/linux-x86/camonitor -h
>
>      Usage: camonitor [options] <PV name> ...
>
>        -h: Help: Print this message
>      Channel Access options:
>        -w <sec>:  Wait time, specifies CA timeout, default is
> 1.000000 second(s)
>        -m <mask>: Specify CA event mask to use, with <mask> being any
> combination of
>                   'v' (value), 'a' (alarm), 'l' (log/archive), 'p'
> (property). Default: va
>        -p <prio>: CA priority (0-99, default 0=lowest)
>      [...]

Sorry, my wording was not clear enough. Sure, camonitor has the -mp 
switch but not -d<dbrtype> (as you acknowledge below). This is what I 
meant. I was trying to add the -d option (to camonitor.pl) and 
initially had some problems, but solved them. See my follow-up message 
with a successfully hacked camonitor.pl.

> > Looking at 'camonitor -h' I see no option for specifying the DBR
> > type, so it seems that --apart from timestamp and status/severity--
> > properties are not supported yet.
>
> Correct.
>
> The camonitor tool is aimed at looking at the timestamped values of
> many PVs over time. To keep the output readable, it follows the rule
> "one line per update".
> To caget that rule does not apply, so it does support all available
> data types, producing a multi-line output for any of the complex
> types.
>
> I would think that camonitor for the complex structures would yield a
> hard to read, if not unusable output.
> Of course: If you have a valid use case, please file a bug report
> explaining your case and including ideas how the camonitor output
> should look like for the complex types. I will seriously consider it,
> that's for sure.

(1) The OP asked for it.
(2) What use is 'camonitor -mp' if I can't see the properties?
(3) I don't think it is hard to read. Try my hacked version of
    camonitor.pl, I use the same format (in fact the same code) as
    caget.pl. It's a bit bulky but note that properties typically don't
    change as frequently as the value.

On Donnerstag, 16. September 2010, Andrew Johnson wrote:
> We could provide an option to output the complex structures using
> JSON, 

What is the problem with using the same format as caget(.pl) uses?

> Having created the above example I realize one problem with the
> DBR_CTRL_xxx types is that they don't include a time-stamp, so
> they're not very good for monitoring values that change over time.

It is still useful. Most times I use camonitor I don't even look once at 
the timestamps. We can also use client-side timestamps.

Cheers
Ben

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System