Re: I implemented the Model 3 of EPICS motor driver support, but the VAL and RBV of motor record are zero after IOC reboot.

[LiangChih Chiang via Tech-talk <tech-talk at aps.anl.gov>]

I added epicsThreadSleep(1.0) after creating motor controller and axes.

I use camonitor to trace the VAL/RBV of motor records of three axes.
I rebooted ioc nine times.
Please see the following log.

I noticed that axes Z1 and Z2 successfully restored the VAL/RBV from the controller every time.

But the behavior of axis ThetaM is strange.
Two out of nine reboots, the VAL field of ThetaM record is successfully restored.
One out of nine reboots, the VAL field of ThetaM record is set to zero.
Six out of nine reboots, the VAL field of ThetaM record is set to (previous value - 0.02).

Why -0.02?


DCM:Z1.VAL                 2025-01-02 16:28:46.483683 -0.04  
DCM:Z1.RBV                 2025-01-02 16:28:46.483683 -0.0401  
DCM:Z2.VAL                 2025-01-02 20:41:47.713687 0.0657  
DCM:Z2.RBV                 2025-01-02 20:41:47.713687 0.0653  
DCM:ThetaM.VAL             2025-01-02 16:28:50.353358 7.53376  <--
DCM:ThetaM.RBV             2025-01-02 16:28:50.353358 7.53376  

ioc reboot

DCM:Z1.VAL                 2025-01-03 08:46:20.410653 -0.0401  
DCM:Z1.RBV                 2025-01-03 08:46:20.410653 -0.04  
DCM:Z2.VAL                 2025-01-03 08:46:20.350513 0.0653  
DCM:Z2.RBV                 2025-01-03 08:46:20.350513 0.0657  
DCM:ThetaM.VAL             2025-01-03 08:46:20.500699 7.53376   <-- same as previous
DCM:ThetaM.RBV             2025-01-03 08:46:20.500699 7.53376  

ioc reboot

DCM:Z1.VAL                 2025-01-03 08:54:04.045355 -0.04  
DCM:Z1.RBV                 2025-01-03 08:54:04.045355 -0.0401  
DCM:Z2.VAL                 2025-01-03 08:54:03.985246 0.0657  
DCM:Z2.RBV                 2025-01-03 08:54:03.985246 0.0653  
DCM:ThetaM.VAL             2025-01-03 08:54:05.156115 7.51376   <-- different -0.02
DCM:ThetaM.RBV             2025-01-03 08:54:05.156115 7.52741   <-- motor move
DCM:ThetaM.RBV             2025-01-03 08:54:05.335235 7.52131  
DCM:ThetaM.RBV             2025-01-03 08:54:05.505113 7.51621  
DCM:ThetaM.RBV             2025-01-03 08:54:05.675255 7.51376  
DCM:ThetaM.RBV             2025-01-03 08:54:05.845205 7.51361  
DCM:ThetaM.VAL             2025-01-03 08:54:05.845205 7.51376  
DCM:ThetaM.RBV             2025-01-03 08:54:05.995251 7.51356  
DCM:ThetaM.RBV             2025-01-03 08:54:06.495140 7.51371  
DCM:ThetaM.RBV             2025-01-03 08:54:06.795186 7.51376  
DCM:ThetaM.RBV             2025-01-03 08:54:06.965241 7.51381  

ioc reboot

DCM:Z1.VAL                 2025-01-03 09:00:47.829590 -0.0401  
DCM:Z1.RBV                 2025-01-03 09:00:47.829590 -0.04  
DCM:Z2.VAL                 2025-01-03 09:00:47.769508 0.0653  
DCM:Z2.RBV                 2025-01-03 09:00:47.769508 0.0657  
DCM:ThetaM.VAL             2025-01-03 09:00:49.279478 7.49377   <-- different -0.01999
DCM:ThetaM.RBV             2025-01-03 09:00:49.279478 7.49611   <-- motor move
DCM:ThetaM.RBV             2025-01-03 09:00:49.449660 7.49371  
DCM:ThetaM.RBV             2025-01-03 09:00:49.619596 7.49351  
DCM:ThetaM.VAL             2025-01-03 09:00:49.619596 7.49377  
DCM:ThetaM.RBV             2025-01-03 09:00:49.939543 7.49356  
DCM:ThetaM.RBV             2025-01-03 09:00:50.269661 7.49376  


Manually move ThetaM to 7.553761  

DCM:ThetaM.VAL             2025-01-03 09:04:05.044900 7.55378  
DCM:ThetaM.VAL             2025-01-03 09:04:05.045646 7.55376  
DCM:ThetaM.RBV             2025-01-03 09:04:05.371519 7.49566  
DCM:ThetaM.RBV             2025-01-03 09:04:05.541574 7.50071  
DCM:ThetaM.RBV             2025-01-03 09:04:05.711567 7.50711  
DCM:ThetaM.RBV             2025-01-03 09:04:05.881592 7.51536  
DCM:ThetaM.RBV             2025-01-03 09:04:06.061484 7.52551  
DCM:ThetaM.RBV             2025-01-03 09:04:06.231575 7.53506  
DCM:ThetaM.RBV             2025-01-03 09:04:06.402009 7.54296  
DCM:ThetaM.RBV             2025-01-03 09:04:06.571571 7.54866  
DCM:ThetaM.RBV             2025-01-03 09:04:06.741529 7.55221  
DCM:ThetaM.RBV             2025-01-03 09:04:06.911574 7.55296  
DCM:ThetaM.VAL             2025-01-03 09:04:06.911574 7.55376  
DCM:ThetaM.RBV             2025-01-03 09:04:07.071671 7.55301  
DCM:ThetaM.RBV             2025-01-03 09:04:07.241982 7.55326  
DCM:ThetaM.RBV             2025-01-03 09:04:07.561637 7.55381  
DCM:ThetaM.RBV             2025-01-03 09:04:07.881647 7.55346  
DCM:ThetaM.RBV             2025-01-03 09:04:08.211724 7.55356  
DCM:ThetaM.RBV             2025-01-03 09:04:08.531501 7.55376  

ioc reboot

DCM:Z1.VAL                 2025-01-03 09:05:56.102804 -0.04  
DCM:Z1.RBV                 2025-01-03 09:05:56.102804 -0.0401  
DCM:Z2.VAL                 2025-01-03 09:05:56.042681 0.0657  
DCM:Z2.RBV                 2025-01-03 09:05:56.042681 0.0653  
DCM:ThetaM.VAL             2025-01-03 09:05:56.174482 7.55376   <-- same as previous
DCM:ThetaM.RBV             2025-01-03 09:05:56.174482 7.55376   <-- but motor move
DCM:ThetaM.RBV             2025-01-03 09:05:57.012778 7.55206  
DCM:ThetaM.RBV             2025-01-03 09:05:57.502889 7.54196  
DCM:ThetaM.RBV             2025-01-03 09:05:57.822823 7.54366  
DCM:ThetaM.RBV             2025-01-03 09:05:57.992678 7.54791  
DCM:ThetaM.RBV             2025-01-03 09:05:58.162720 7.55171  
DCM:ThetaM.RBV             2025-01-03 09:05:58.342759 7.55266  
DCM:ThetaM.RBV             2025-01-03 09:05:58.492806 7.55271  
DCM:ThetaM.RBV             2025-01-03 09:05:58.662711 7.55371  
DCM:ThetaM.RBV             2025-01-03 09:05:58.962828 7.55376  
DCM:ThetaM.RBV             2025-01-03 09:05:59.132771 7.55381  
DCM:ThetaM.RBV             2025-01-03 09:06:02.762853 7.55386  

ioc reboot

DCM:Z1.VAL                 2025-01-03 09:09:37.385148 -0.0401  
DCM:Z1.RBV                 2025-01-03 09:09:37.385148 -0.04  
DCM:Z2.VAL                 2025-01-03 09:09:37.325204 0.0653  
DCM:Z2.RBV                 2025-01-03 09:09:37.325204 0.0657  
DCM:ThetaM.VAL             2025-01-03 09:09:38.354986 0         <-- different, zero!
DCM:ThetaM.RBV             2025-01-03 09:09:38.354986 7.55181   <-- motor move
DCM:ThetaM.RBV             2025-01-03 09:09:38.535008 7.54706  
DCM:ThetaM.RBV             2025-01-03 09:09:38.704917 7.54026  
DCM:ThetaM.RBV             2025-01-03 09:09:38.875048 7.53131  
DCM:ThetaM.RBV             2025-01-03 09:09:39.045385 7.52046  
DCM:ThetaM.RBV             2025-01-03 09:09:39.215134 7.50731  
DCM:ThetaM.RBV             2025-01-03 09:09:39.385166 7.49361  
DCM:ThetaM.RBV             2025-01-03 09:09:39.555112 7.48036  
DCM:ThetaM.RBV             2025-01-03 09:09:39.725153 7.46636  
DCM:ThetaM.RBV             2025-01-03 09:09:39.894942 7.45281  
DCM:ThetaM.RBV             2025-01-03 09:09:40.064989 7.43961  
DCM:ThetaM.RBV             2025-01-03 09:09:40.234971 7.42526  
DCM:ThetaM.RBV             2025-01-03 09:09:40.405113 7.41221  
DCM:ThetaM.RBV             2025-01-03 09:09:40.585072 7.39761  
DCM:ThetaM.RBV             2025-01-03 09:09:40.755044 7.38401  
DCM:ThetaM.RBV             2025-01-03 09:09:40.925113 7.37066  
DCM:ThetaM.RBV             2025-01-03 09:09:42.095077 7.31426  
DCM:ThetaM.VAL             2025-01-03 09:09:42.095077 7.31426  <-- I stop the motor.
DCM:ThetaM.RBV             2025-01-03 09:09:46.705116 7.31421  

ioc reboot

DCM:Z1.VAL                 2025-01-03 09:12:18.906995 -0.04  
DCM:Z1.RBV                 2025-01-03 09:12:18.906995 -0.0401  
DCM:Z2.VAL                 2025-01-03 09:12:18.846984 0.0657  
DCM:Z2.RBV                 2025-01-03 09:12:18.846984 0.0653  
DCM:ThetaM.VAL             2025-01-03 09:12:21.346979 7.29431   <-- different −0.01995
DCM:ThetaM.RBV             2025-01-03 09:12:21.346979 7.29431   <-- motor move

ioc reboot

DCM:Z1.VAL                 2025-01-03 09:18:20.230656 -0.0401  
DCM:Z1.RBV                 2025-01-03 09:18:20.230656 -0.04  
DCM:Z2.VAL                 2025-01-03 09:18:20.170608 0.0653  
DCM:Z2.RBV                 2025-01-03 09:18:20.170608 0.0657  
DCM:ThetaM.VAL             2025-01-03 09:18:20.311337 7.27437   <-- different −0.01994
DCM:ThetaM.RBV             2025-01-03 09:18:20.311337 7.29431   <-- motor move
DCM:ThetaM.RBV             2025-01-03 09:18:21.150538 7.29231  
DCM:ThetaM.RBV             2025-01-03 09:18:21.320404 7.28771  
DCM:ThetaM.RBV             2025-01-03 09:18:21.500407 7.28171  
DCM:ThetaM.RBV             2025-01-03 09:18:21.670389 7.27681  
DCM:ThetaM.RBV             2025-01-03 09:18:21.840686 7.27421  
DCM:ThetaM.RBV             2025-01-03 09:18:22.010457 7.27406  
DCM:ThetaM.VAL             2025-01-03 09:18:22.010457 7.27437  
DCM:ThetaM.RBV             2025-01-03 09:18:22.330451 7.27421  
DCM:ThetaM.RBV             2025-01-03 09:18:22.660350 7.27431  
DCM:ThetaM.RBV             2025-01-03 09:18:22.960309 7.27436  
DCM:ThetaM.RBV             2025-01-03 09:18:23.130896 7.27441  

ioc reboot

DCM:Z1.VAL                 2025-01-03 09:22:00.722740 -0.04  
DCM:Z1.RBV                 2025-01-03 09:22:00.722740 -0.0401  
DCM:Z2.VAL                 2025-01-03 09:22:00.662695 0.0657  
DCM:Z2.RBV                 2025-01-03 09:22:00.662695 0.0653  
DCM:ThetaM.VAL             2025-01-03 09:22:02.912859 7.25442   <-- different −0.01995
DCM:ThetaM.RBV             2025-01-03 09:22:02.912859 7.25441   <-- motor move

ioc reboot

DCM:Z1.VAL                 2025-01-03 09:33:58.400417 -0.0401  
DCM:Z1.RBV                 2025-01-03 09:33:58.400417 -0.04  
DCM:Z2.VAL                 2025-01-03 09:33:58.340350 0.0653  
DCM:Z2.RBV                 2025-01-03 09:33:58.340350 0.0657  
DCM:ThetaM.VAL             2025-01-03 09:33:59.330344 7.23447   <-- different −0.01995
DCM:ThetaM.RBV             2025-01-03 09:33:59.330344 7.25241   <-- motor move
DCM:ThetaM.RBV             2025-01-03 09:33:59.500272 7.24781  
DCM:ThetaM.RBV             2025-01-03 09:33:59.680584 7.24186  
DCM:ThetaM.RBV             2025-01-03 09:33:59.850291 7.23701  
DCM:ThetaM.RBV             2025-01-03 09:34:00.020355 7.23431  
DCM:ThetaM.RBV             2025-01-03 09:34:00.190267 7.23416  
DCM:ThetaM.VAL             2025-01-03 09:34:00.190267 7.23447  
DCM:ThetaM.RBV             2025-01-03 09:34:00.510337 7.23431  
DCM:ThetaM.RBV             2025-01-03 09:34:00.840415 7.23441  
DCM:ThetaM.RBV             2025-01-03 09:34:01.140389 7.23446  
DCM:ThetaM.RBV             2025-01-03 09:34:01.310255 7.23451  

On Thu, Jan 2, 2025 at 11:26 AM LiangChih Chiang <yehnan174 at gmail.com> wrote:

Hi,

>To explain a little more, it is important that the driver has completed the first poll cycle for the position and status of each axis before iocInit.  

>This is because the motor record looks at those positions during iocInit, and if there are non-zero it uses those values as the current position.  

>You can add the following to your startup script after you create the controller and axes to sleep for 1 second.

>epicsThreadSleep(1.0)

I did add epicsThreadSleep(1.0).

There are 5 motors(axis 1 to 5) connected to the motor controller.

After epicsThreadSleep(1.0) added, it seems that the VAL/RBV of motor records of axis 2 to 5 can be successfully loaded back from the controller after IOC reboot.

But the behavior of axis 0 (this axis is the most important) is strange.

After IOC reboot, the motor record of axis 0 will move.

It seems that the VAL field is set to a new value

and I can't figure out the relationship between the new and old values.

The axis 0 is the main axis(Bragg angle) of a double crystal monochromator,

and it has corresponding pseudo motor to represent the Energy of x-ray beam.

On Wed, Nov 20, 2024 at 11:04 PM Mark Rivers <rivers at cars.uchicago.edu> wrote:

To explain a little more, it is important that the driver has completed the first poll cycle for the position and status of each axis before iocInit.  This is because the motor record looks at those positions during iocInit, and if there are non-zero it uses those values as the current position.  You can add the following to your startup script after you create the controller and axes to sleep for 1 second.

epicsThreadSleep(1.0)

Let us know if this does not fix the problem.

Mark

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Torsten Bögershausen via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, November 20, 2024 5:15 AM
To: LiangChih Chiang <yehnan174 at gmail.com>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: I implemented the Model 3 of EPICS motor driver support, but the VAL and RBV of motor record are zero after IOC reboot.

 

Hej,

without having seen ypur code, I would speculate that you run
into a not-unknown issue using Model 3 motors, connected via
a serial cable, USB or Ethernet?

The value that the motorRecord needs is read from the driver,
wich must have been able to read it from your hardware.
Here are ESS we have a patched motor, which can handle this.
If you use the upstream version, the easist workaround may be
to add a sleep() after the createController() line in your st.cmd

HTH
/Torsten


On 2024-11-20 09:47, LiangChih Chiang via Tech-talk wrote:
> Hello, EPICS mates.
>
> I implemented the Model 3 of EPICS motor driver support for some motor
> controller,
> but the VAL and RBV of the motor record are zero after IOC reboot.
>
> I think the motor record doesn't restore the values of motor pulse and
> encoder count from the motor controller after IOC reboot.
>
> What member functions of asynMotorController and asynMotorAxis classes
> should I implement?
>
>
> Best regards.
>