Remora - ethernet NVEM / EC300 / EC500 cnc board

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3 years 7 months ago #266436 by scotta
Replied by scotta on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
Took some digging, but finally found it. 
Code:
# load the real-time components     loadrt remora-eth     loadrt estop_latch     loadrt and2 # estop and comms enable and feedback     net nvem-estop             <= estop-latch.0.fault-in             <= remora.input.4     net user-enable-in         <= and2.0.out                         => iocontrol.0.emc-enable-in     net remora-status        <= remora.status                    => and2.0.in0     net estop-status        <= estop-latch.0.ok-out                => and2.0.in1          net user-enable-out        <= iocontrol.0.user-enable-out        => remora.enable     net user-enable-out                                             => estop-latch.0.ok-in     net user-request-enable <= iocontrol.0.user-request-enable    => remora.reset     net user-request-enable                                     => estop-latch.0.reset # add the remora and motion functions to threads     addf remora.read             servo-thread     addf estop-latch.0             servo-thread     addf and2.0                    servo-thread     addf motion-command-handler servo-thread     addf motion-controller         servo-thread     addf remora.update-freq     servo-thread     addf remora.write             servo-thread

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3 years 7 months ago #266629 by frayja2002
Replied by frayja2002 on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
Hi there

Thanks for that. I managed to get it working. I have attached what I ended up with in case it is useful to someone else.

I do have another question though. I am using a STM32 based NVEM controller on a small 2040 style mill. This is using NEMA 17 motors.

When I jog any of the axis (around 100mm) the axis stops short (about .04 of a mm) and then gradually moves to the commanded position. Just by counting this can take up to 2 sec. for the axis to stop moving.

Is this expected behavior & how do I go about diagnosing this?

Thanks
Alex.

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3 years 7 months ago #266630 by scotta
Replied by scotta on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
There is a deadband in the control loop which by default is deadband = 1 / data->pos_scale. This can be overwritten by a command line setting.

0.04mm must be very close to 1 step, so the control loop is trying to get it as close as possible.

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3 years 7 months ago #266631 by cakeslob
Replied by cakeslob on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
I have been wondering why more people havent asked about that. I figured they had higher step scales so it went unnoticed. It took me a while to figure out what was going on. I only found reference to it in a couple config files. This config has a deadband example
github.com/scottalford75/Remora/tree/mai...s/remora-closed-loop

1 / data->pos_scale, I dont know the math on that but it seems high because the default gives me unacceptable results. When I set deadband to something like .005mm, or half of 1 step it eliminates the issue.
github.com/cakeslob/upload_things/issues/1

I havent used deadband setting with openloop steppers before, what is the benefit of a higher deadband setting?

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3 years 7 months ago #266632 by scotta
Replied by scotta on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
1 / data->pos_scale should give a deadband of exactly one step

eg, from my 3D printer config. SCALE = 160 (steps/mm) giving a deadband of 0.00625mm

If the deadband is smaller than one step then the loop will hunt as it can never physically achieve the commanded position. This was an issue I ran into with the earlier versions of the Remora component.

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3 years 7 months ago #266649 by frayja2002
Replied by frayja2002 on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
So how would you apply this with a stepper system that doesn't have any feed back?

Thanks
Alex

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3 years 7 months ago #266699 by scotta
Replied by scotta on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
LinuxCNC actually does this with steppers, both the standard stepgen component and the Remora firmware close the loop by feeding back the number of steps outputted. Of course this cannot take into account any physical lost steps.

This is the difference between LinuxCNC and other software like Marlin or Klipper and is why you can get following errors with steppers with LinuxCNC.

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3 years 7 months ago #266700 by frayja2002
Replied by frayja2002 on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
Sorry, you are talking at to much of a high level for me.

How do I put this

1 / data->pos_scale

into my ini file to adjust it.
Should it actually be in the hal file?

Thanks

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3 years 7 months ago #266701 by scotta
Replied by scotta on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
No need to do anything. It's already how the Remora component code is unless overridden by setting a value on the deadband pin.

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3 years 7 months ago #266715 by cakeslob
Replied by cakeslob on topic Remora - ethernet NVEM / EC300 / EC500 cnc board
frayja, you would add these lines to each joint in the INI file and and the hal file

github.com/scottalford75/Remora/blob/mai...-loop/remora.hal#L50

github.com/scottalford75/Remora/blob/mai...-loop/remora.ini#L96

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