Re: How can I use pvapy or p4p to monitor multiple PVS

["Veseli, Sinisa via Tech-talk" <tech-talk at aps.anl.gov>]

Hello,

Here are the pvapy examples that monitor multiple channels: 

https://github.com/epics-base/pvaPy/blob/master/examples/scaleN.py

https://github.com/epics-base/pvaPy/blob/master/examples/spamN.py

The above should work for tens of thousands pv's that update at a rate of 1Hz or so.

Also, the latest pvapy documentation can be found here: https://epics.anl.gov/extensions/pvaPy/production/index.html.

Best Regards,

Sinisa

--

Siniša Veseli

Scientific Software Engineering & Data Management

Advanced Photon Source

Argonne National Laboratory

sveseli at anl.gov

(630)252-9182

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of =?utf-8?b?56em5aSpIHZpYSBUZWNoLXRhbGsgPHRlY2gtdGFsa0BhcHMuYW5sLmdv?=@aps.anl.gov <=?utf-8?b?56em5aSpIHZpYSBUZWNoLXRhbGsgPHRlY2gtdGFsa0BhcHMuYW5sLmdv?=@aps.anl.gov>
Sent: Tuesday, October 13, 2020 7:18 AM
To: Rivers, Mark L. <rivers at cars.uchicago.edu>; Marty Kraimer <mrkraimer at comcast.net>; tech-talk <tech-talk at aps.anl.gov>
Subject: Re: How can I use pvapy or p4p to monitor multiple PVS

 

Thank you for your answer.I've solved my problem.
I need to loop to create an associated class object for each pv.Then use each class object to execute the monitor function.
For example
 |  for i in range(51):
 |	if pvnames[i] == 'xkSun:test50Scalar:aiExample1':
 |          globals()['pv' + str(i)] = pv_monitor(pvnames[i])
 |          globals()['pv' + str(i)].my_monitor()
 |  def my_monitor(self):
 |     ctxt.monitor(self.pv, self.onChanges)

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Subject:
Re:
 How can I use pvapy or p4p to monitor multiple PVS
From:
Marty Kraimer via Tech-talk <tech-talk
 at aps.anl.gov>
To:
tech-talk at aps.anl.gov
Date:
Tue,
 13 Oct 2020 06:06:15 -0400
What Mark said should work.
Note that pvaPy also has methods: subscribe,unsubscribe,startMonitor,stopMonitor.
For example
 |             def echo(x):
 |                  print 'New PV value: ', x
 |              channel = Channel('exampleFloat')
 |              channel.subscribe('echo', echo)
 |              channel.startMonitor()

Marty

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Subject:
Re: How can I use pvapy
 or p4p to monitor multiple PVS
From:
Mark Rivers via Tech-talk <tech-talk
 at aps.anl.gov>
To:
"qt980319 at mail.ustc.edu.cn" <qt980319
 at mail.ustc.edu.cn>
Cc:
"sunxk at ustc.edu.cn" <sunxk
 at ustc.edu.cn>, "tech-talk at aps.anl.gov" <tech-talk
 at aps.anl.gov>
Date:
Tue, 13 Oct 2020 03:54:32 +0000
However, in the process of testing it, it was found that only a single PV can be monitored

In p4p can’t you just call the monitor() method multiple times, once for each PV that you want to monitor?

In pvapy can’t you just create a Channel object for each PV, and call it’s monitor() method?

Mark

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