Re: help! can the epics monitor many pv in the same time,thanks

["Dudley, David" <ddudley@bnl.gov>]

Is the question concerning the number of channels that can be monitored and archived (which as Leo said, is very large, into the many thousands), or are you asking specifically about ‘simultaneous monitoring’, grabbing many channels at exactly the same point in time?

EPICS can acquire and archive many, many channels, but each channel will be acquired at -slightly- different time.  As far as I know, you can’t do something like a triggered, simultaneous acquisition of a number of channels (say, 50…100) at precisely the same point in time without specific hardware capable of performing that function.  There are many devices (both commercially available, and custom manufactured) that can be interfaced to the EPICS system that can do that function, and provide that information to EPICS. 

Later-

David Dudley

ddudley@bnl.gov

On Mar 11, 2014, at 6:59 AM, Ralph Lange <Ralph.Lange@gmx.de> wrote:

Adding some links...

Hope this gets you started,
~Ralph


On Tue Mar 11 2014 11:29:27 GMT+0100 (CET), Dalesio, Leo
<dalesio@bnl.gov> wrote:

There are archiver appliances that are monitoring 10's of thousands of channels.

[1, 2, 3]

Care has to be taken about the rate of these monitors. Please read the EPICS Record Reference Manual

[4]

regarding how to deadband monitors for archiving alarms and value monitors. Please read the Application Developers Guide

[5]

and Channel Access Reference Manual

[6]

for ways to monitor and deal with managing these monitors.

[1] http://sourceforge.net/projects/epicschanarch/
[2] http://controlsystemstudio.org/
[3] http://epicsarchiverap.sourceforge.net/
[4] https://wiki-ext.aps.anl.gov/epics/index.php/RRM_3-14
[5] http://www.aps.anl.gov/epics/base/R3-14/12-docs/AppDevGuide.pdf
[6] http://www.aps.anl.gov/epics/base/R3-14/12-docs/CAref.html