Re: EPICS support for Fastech motors

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

H Rea,

You have set the asynTraceMask to enable lots of debugging.  That is OK, but it makes it hard to see the real errors from warning and informational messages.  For example these messages are printed with ASYN_TRACE_FLOW, they are not really errors.

2026/06/25 15:29:48.311 asynPortDriver:getDoubleParam: port=motorExit error getting parameter 9 MOTOR_ENCODER_POSITION, in list 0, value undefined
2026/06/25 15:29:48.311 asynPortDriver:getDoubleParam: port=motorExit error getting parameter 5 MOTOR_VELOCITY, in list 0, value undefined

This message

2026/06/25 15:07:46.444 asynMotorController:writeFloat64: Set driver motorExit, axis 0 move absolute to 0.000000, base velocity=500.000000, velocity=25000.000000, acceleration=245000.000000

is being printed here.  It is just an informational message.

https://github.com/epics-modules/motor/blob/f3d089bae20d04f8b9ed18fcfdc55274075d6a42/motorApp/MotorSrc/asynMotorController.cpp#L328

However, this message:

2026/06/25 15:07:46.445 asynMotorController:writeFloat64 error, status=1 axis=0, function=1, value=0.000000

is being printed here:

https://github.com/epics-modules/motor/blob/f3d089bae20d04f8b9ed18fcfdc55274075d6a42/motorApp/MotorSrc/asynMotorController.cpp#L428

Function=1 is a move absolute command, so it is consistent with the first message.  status=1 means that your driver's pAxis->move() function returned -1.  It was called from here:

https://github.com/epics-modules/motor/blob/f3d089bae20d04f8b9ed18fcfdc55274075d6a42/motorApp/MotorSrc/asynMotorController.cpp#L324-L325

If you set your asynTrace flags to ERROR|WARNING you will only see the more important messages.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Rea Domitrović via Tech-talk <tech-talk at aps.anl.gov>
Sent: Thursday, June 25, 2026 8:53 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: EPICS support for Fastech motors

 

Hi all,

thanks so much for pointing me in the right direction so far. I've got to the point where I've got the structure of a driver based on the MCB4B driver and with inspiration from the SmarAct driver; however, at runtime, I'm getting errors that I'm struggling to diagnose. If someone could help me understand, I would be most grateful. Relevant info is below. Best,

Rea Domitrović

Institut Ruđer Bošković

Zagreb, Croatia

Source code is here: https://github.com/redomitro/motorFastech

IOCinit output:

2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_MOVE_REL, index=0
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_MOVE_ABS, index=1
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_MOVE_VEL, index=2
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_HOME, index=3
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_STOP_AXIS, index=4
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_VELOCITY, index=5
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_VEL_BASE, index=6
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_ACCEL, index=7
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_POSITION, index=8
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_RESOLUTION, index=12
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_ENCODER_RATIO, index=13
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_PGAIN, index=14
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_IGAIN, index=15
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_DGAIN, index=16
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_HIGH_LIMIT, index=17
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_LOW_LIMIT, index=18
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_CLOSED_LOOP, index=19
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_STATUS, index=25
2026/06/25 15:29:48.311 asynPortDriver:drvUserCreate: drvInfo=MOTOR_UPDATE_STATUS, index=26
2026/06/25 15:29:48.311 motorExit 0 registerInterruptUser
2026/06/25 15:29:48.311 asynPortDriver:getDoubleParam: port=motorExit error getting parameter 9 MOTOR_ENCODER_POSITION, in list 0, value undefined
2026/06/25 15:29:48.311 asynPortDriver:getDoubleParam: port=motorExit error getting parameter 5 MOTOR_VELOCITY, in list 0, value undefined
2026/06/25 15:29:48.311 asynMotorController:readGenericPointer: MotorStatus = status34, position=425203751.000000, encoder position=0.000000, velocity=0.000000
2026/06/25 15:29:48.311 motorExit asynManager::queueLockPort locking port
2026/06/25 15:29:48.311 motorExit asynManager::queueLockPort created queueLockPortPvt=0x561069c8f7a0
2026/06/25 15:29:48.311 motorExit asynManager::queueLockPort created queueLockPortPvt=0x561069c8f7a0, event=0x561069c979e0, mutex=0x561069c97990
2026/06/25 15:29:48.311 motorExit asynManager::queueLockPort taking mutex 0x561069c97990
2026/06/25 15:29:48.311 motorExit asynManager::queueLockPort queueing request
2026/06/25 15:29:48.311 motorExit addr 0 queueRequest priority 0 not lockHolder
2026/06/25 15:29:48.311 motorExit schedule queueRequest timeout in 2.000000 seconds
2026/06/25 15:29:48.311 motorExit asynManager::queueLockPort waiting for event
2026/06/25 15:29:48.312 motorExit 0 autoConnect
2026/06/25 15:29:48.312 asynPortDriver:connect:, pasynUser=0x561069c83188
2026/06/25 15:29:48.312 asynManager::portThread port=motorExit callback
2026/06/25 15:29:48.312 motorExit asynManager::queueLockPortCallback signaling begin event
2026/06/25 15:29:48.312 motorExit asynManager::queueLockPortCallback waiting for mutex from queueUnlockPort
2026/06/25 15:29:48.312 motorExit asynManager::queueLockPort got event from callback
2026/06/25 15:29:48.312 EXIT:zpos devMotorAsyn::statusCallback new value=[p:425203751.000000,e:0.000000,s:22]
2026/06/25 15:29:48.312 asynMotorController:writeFloat64: Set driver motorExit, axis 0 encoder ratio=1.000000
2026/06/25 15:29:48.312 asynMotorController:writeFloat64:: axis=0, function=13, value=1.000000
2026/06/25 15:29:48.312 asynFloat64SyncIO wrote: 1.000000e+00
2026/06/25 15:29:48.312 motorExit queueUnlockPort
2026/06/25 15:29:48.312 motorExit asynManager::queueUnlockPort waiting for event
2026/06/25 15:29:48.313 motorExit queueUnlockPort unlock mutex 0x561069c97990 complete.
2026/06/25 15:29:48.313 devMotorAsyn::init_controller, EXIT:zpos set encoder ratio to 1.000000
2026/06/25 15:29:48.313 devMotorAsyn::init_controller, EXIT:zpos setting of position not required, position=425203751.000000, mres=0.000200, dval=0.000000, rdbd=0.0002002026/06/25 15:29:48.313 EXIT:zpos devMotorAsyn::update_values, needUpdate=1
2026/06/25 15:29:48.313 devMotorAsyn::build_trans: EXIT:zpos motor_cmnd=19, pact=0, value=375000.000000
2026/06/25 15:29:48.313 devAsynMotor::build_trans: calling queueRequest, pmsg=0x561069c97c40, sizeof(*pmsg)=24pmsg->command=14, pmsg->interface=1, pmsg->dvalue=375000.000000
2026/06/25 15:29:48.313 motorExit addr 0 queueRequest priority 0 not lockHolder
2026/06/25 15:29:48.313 devMotorAsyn::build_trans: EXIT:zpos motor_cmnd=20, pact=0, value=-375000.000000
2026/06/25 15:29:48.313 devAsynMotor::build_trans: calling queueRequest, pmsg=0x561069c97c90, sizeof(*pmsg)=24pmsg->command=15, pmsg->interface=1, pmsg->dvalue=-375000.000000
2026/06/25 15:29:48.313 motorExit addr 0 queueRequest priority 0 not lockHolder
2026/06/25 15:29:48.313 asynManager::portThread port=motorExit callback
2026/06/25 15:29:48.313 devMotorAsyn::asynCallback: EXIT:zpos pmsg=0x561069c97c40, sizeof(*pmsg)=24, pmsg->command=14,pmsg->interface=1, pmsg->ivalue=0, pmsg->dvalue=375000.000000, pasynUser->reason=17
2026/06/25 15:29:48.313 asynMotorController:writeFloat64: Set driver motorExit, axis 0 high limit=375000.000000
2026/06/25 15:29:48.313 asynMotorController:writeFloat64:: axis=0, function=17, value=375000.000000
2026/06/25 15:29:48.313 asynManager::portThread port=motorExit callback
2026/06/25 15:29:48.313 devMotorAsyn::asynCallback: EXIT:zpos pmsg=0x561069c97c90, sizeof(*pmsg)=24, pmsg->command=15,pmsg->interface=1, pmsg->ivalue=0, pmsg->dvalue=-375000.000000, pasynUser->reason=18
2026/06/25 15:29:48.313 asynMotorController:writeFloat64: Set driver motorExit, axis 0 low limit=-375000.000000
2026/06/25 15:29:48.313 asynMotorController:writeFloat64:: axis=0, function=18, value=-375000.000000

Output when attempting to caput absolute position:

2026/06/25 15:07:44.438 192.168.0.204:3001 UDP write 3
\xaa\v\a
2026/06/25 15:07:46.444 asynMotorController:writeFloat64: Set driver motorExit, axis 0 move absolute to 0.000000, ba                                                                                                                        se velocity=500.000000, velocity=25000.000000, acceleration=245000.000000
2026/06/25 15:07:46.445 asynMotorController:writeFloat64 error, status=1 axis=0, function=1, value=0.000000
2026/06/25 15:07:46.445 devMotorAsyn::asynCallback: EXIT:zpos pasyn{Float64,Int32}->write returned
2026/06/25 15:07:46.445 EXIT:zpos devMotorAsyn::update_values, needUpdate=1

---

From: Mark Rivers <rivers at cars.uchicago.edu>
Sent: Wednesday, June 17, 2026 21:07
To: Torsten Bögershausen; tech-talk at aps.anl.gov; Rea Domitrović
Subject: Re: EPICS support for Fastech motors

 

Hi Rea,

•  I see that driver developers prefer to use octet-based communication rather than use the manufacturer-provided libraries. Is there a reason why that is the case, or is it simply that octet-based communicaton is more universal?

Manufacturer libraries will be provided for specific operating system and specific versions of those OS. That can restrict where they can be deployed.  They may restrict redistribution, which prevents including them in the motor Github repository.  They almost certainly won't be supported on real-time OS like RTEMS or vxWorks.

• Further, the Fastech controller allows both octet-based communication and library-based communication, but octet-based communication requires the master to send a one-byte "sync number" which serves as an idempotence token. I assume it would be necessary to implement that myself; could I be using some sort of global variable, and how do I make sure that I never land on the same number twice in a row?

Many protocols have something like that.  You just have a member variable in your driver class that increments by 1 on each message it sends, and wraps back to 0 after 255.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Rea Domitrović via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, June 17, 2026 8:34 AM
To: Torsten Bögershausen <tboegi at edom.se>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: EPICS support for Fastech motors

Hi Torsten,

thanks for pointing me in the right direction. I'm looking at the manual and the source for other submodules now (motorSmarAct and motorAcs); I see that driver developers prefer to use octet-based communication rather than use the manufacturer-provided libraries. Is there a reason why that is the case, or is it simply that octet-based communicaton is more universal?

Further, the Fastech controller allows both octet-based communication and library-based communication, but octet-based communication requires the master to send a one-byte "sync number" which serves as an idempotence token. I assume it would be necessary to implement that myself; could I be using some sort of global variable, and how do I make sure that I never land on the same number twice in a row? Kind regards,

Rea

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From: Torsten Bögershausen <tboegi at edom.se>
Sent: Wednesday, June 10, 2026 1:49:41 PM
To: Rea Domitrović; tech-talk at aps.anl.gov
Subject: Re: EPICS support for Fastech motors

 

Hej Rea,

I haven't worked with them, no.
If you have Ethernet (not to be confused with EtherCAT),
I read the manual as if they use UDP for communication,
and knowing that you can write a simple model 3 driver, I think.
(Other suggestions are welcome of course)
/Torsten


On 2026-06-10 12:52, Rea Domitrović via Tech-talk wrote:
> Hi all,
>
>
> I'm working with some Fastech Ezi-Servo II Plus-E motors, and I was
> wondering if someone had already worked with them and/or made an EPICS
> driver or Motor submodule? This particular line of motors and
> drives uses an Ethernet interface. Kind regards,
>
>
> Rea Domitrović
>
> Institut Ruđer Bošković
>
> Zagreb, Croatia
>

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