RE: Finding out what's commanding motor move?

[Mark Rivers via Tech-talk <tech-talk@aps.anl.gov>]

Hi Lewis,

 

You can use the casr command at the IOC shell to see what clients have connected to that PV.

 

epics> casr 2

Channel Access Server V4.13

2 clients connected:

    TCP client at 164.54.160.82:37920 'corvette':

        User 'epics', V4.13, Priority = 0, 150 Channels

        Channel: '13MCBOX:USBCTR:PulseGen2Run'

        Channel: '13MCBOX:USBCTR:PulseGen2Run'

        Channel: '13MCBOX:USBCTR:PulseGen2Run'

...

        Channel: '13MCBOX:USBCTR:Bi4.VAL'

        Channel: '13MCBOX:USBCTR:Bi4.VAL'

        Channel: '13MCBOX:USBCTR:Bi5.VAL'

    TCP client at 164.54.160.227:51915 'Tahoe':

        User 'rivers', V4.13, Priority = 0, 5 Channels

        Channel: '13MCBOX:MCS1:Dwell'

        Channel: '13MCBOX:MCS1:NuseAll'

        Channel: '13MCBOX:MCS1:EraseStart'

        Channel: '13MCBOX:MCS1:StopAll'

        Channel: '13MCBOX:MCS1:mca2'

CAS-TCP server on 0.0.0.0:5064 with

    CAS-UDP name server on 0.0.0.0:5064

        Last name requested by 164.54.160.202:61180:

        User '', V4.13, Priority = 0, 0 Channels

Sending CAS-beacons to 1 address:

    164.54.160.255:5065

 

In this case there are 2 clients, one of corvette and one on tahoe.

 

casr is part of EPICS base, and so you can run it without needing to restart the IOC.

 

 

Another utility is CaPutLog.

https://github.com/epics-modules/caPutLog/blob/master/docs/index.rst

 

That will log all Channel Access put operations.  It is a separate module, so you need to build your IOC with it.

 

Mark

 

-----Original Message-----
From: Tech-talk <tech-talk-bounces@aps.anl.gov> On Behalf Of J. Lewis Muir via Tech-talk
Sent: Friday, October 10, 2025 11:27 AM
To: EPICS Tech-Talk <tech-talk@aps.anl.gov>
Subject: Finding out what's commanding motor move?

 

Hi!

 

I've got an EPICS motor that appears to be being commanded to move in increments of 0.001 mm every ~0.9 s, sometimes pausing maybe once a minute for 3-5 s and then continuing, and I can't figure out where this is coming from.  Nothing should be commanding the motor to move.  Below is a short camonitor output showing this.  Has anyone seen this before, or does anyone know how I could track this down?

 

The environment is the following:

 

* Architecture: x86_64

* EPICS 7.0.8.1

* motor 7.3.1

* motorAcsMotion 2.2 (+ commits up to c2d67e7, + patches for 719d3ca and

  f4442ee)

* Motor controller: ACS SPiiPlusEC

 

I could restart the IOC or the motor controller and see if the problem goes away, but I'm also very puzzled by this and not wanting to lose my chance to figure out what is happening.

 

I wondered if maybe an MEDM client could have gone wrong, or maybe at some point a user had clicked the MEDM motor tweak button rapidly or who knows what, and something has queued up move requests, or an MEDM client has a bug and is sending requests.  I tried killing MEDM clients, but the behavior remains.  (It's possible, though, that I didn't kill all of the MEDM clients.)  And of course, this could have nothing to do with MEDM at all.

 

----

$ camonitor 17idb:m49.{VAL,RBV}

17idb:m49.VAL                  2025-10-10 09:49:09.164067 0.3198

17idb:m49.RBV                  2025-10-10 09:49:09.164067 0.319806

17idb:m49.VAL                  2025-10-10 09:49:09.811336 0.3208

17idb:m49.RBV                  2025-10-10 09:49:09.942664 0.320808

17idb:m49.RBV                  2025-10-10 09:49:10.048250 0.320799

17idb:m49.VAL                  2025-10-10 09:49:10.694218 0.3218

17idb:m49.RBV                  2025-10-10 09:49:10.823829 0.321805

17idb:m49.RBV                  2025-10-10 09:49:10.929981 0.321801

17idb:m49.VAL                  2025-10-10 09:49:11.575012 0.3228

17idb:m49.RBV                  2025-10-10 09:49:11.710083 0.322803

17idb:m49.RBV                  2025-10-10 09:49:11.816005 0.322795

17idb:m49.VAL                  2025-10-10 09:49:12.463081 0.3238

17idb:m49.RBV                  2025-10-10 09:49:12.488690 0.322803

17idb:m49.RBV                  2025-10-10 09:49:12.594706 0.323805

17idb:m49.VAL                  2025-10-10 09:49:13.346730 0.3248

17idb:m49.RBV                  2025-10-10 09:49:13.372604 0.323801

17idb:m49.RBV                  2025-10-10 09:49:13.478568 0.324807

17idb:m49.RBV                  2025-10-10 09:49:13.584573 0.324803

17idb:m49.VAL                  2025-10-10 09:49:14.229819 0.3258

17idb:m49.RBV                  2025-10-10 09:49:14.254400 0.324794

17idb:m49.RBV                  2025-10-10 09:49:14.360413 0.325805

17idb:m49.VAL                  2025-10-10 09:49:15.112347 0.3268

17idb:m49.RBV                  2025-10-10 09:49:15.138748 0.3258

17idb:m49.RBV                  2025-10-10 09:49:15.244889 0.326806

17idb:m49.RBV                  2025-10-10 09:49:15.351075 0.326794

----

 

Thank you!

 

Lewis