ET10 analog servo-driver

Post Reply
oursomatic
Posts: 18
Joined: Mon Mar 09, 2020 2:19 pm

ET10 analog servo-driver

Post by oursomatic »

Hello

I am starting to configure MyCnc for analog closed-loop drive with a ET10 board and I have no succes to activate PID closed-loop to start axis motor tuning.

Here is my situation

I have install live CD of Ubuntu mate with Mycnc pre-installed.

Profil = x1366m
Udp rj45 IP address = ok
Encoder counting = ok
Encoder scale = ok
Servo DAC +/-10v = ok ( 10,15v max )
Servo DAC 0v = 0.004V = ok
Drive enable = ok
Defaults Handler init PLC Parameter 6000,1 = ok
Default Handler exit PLC Parameter 6001,1 = ok
Jog axis speed = 200mm/min
Axis Acceleration = 50mm/s2
-------------------------------------------------
PID analog screen.

When I press x+ or x- servo motor turn in the correct directions ( X+ = encoder count + ) but following error is at maximal limit.

When servo motor are at idle state they have not any stiffness ( against manual counter action )
Like if PID was OFF

When i jog axis I got =

PID K0 = 00 >> motor speed is nul
PID k0 = 10 >> motor speed is slow // follow error is infinite
PID k0 = 100 >> motor speed is high // follow error is infinite


If I try different value for P / D / I the result is the same as before about stifness.

I have no closed-loop controls.

I forgot something but what ?

ivan
Posts: 278
Joined: Tue Apr 16, 2019 5:30 pm
Location: Ottawa, Canada

Re: ET10 analog servo-driver

Post by ivan »

It seems like you might be getting a positive feedback loop causing you to go to infinity. Try switching the coefficient from 10 to -10, or alternatively try flipping the encoder direction by switching the A and /A wires around. Let me know if that helps.

We will also be preparing a full video manual on setting up the closed loop system from the myCNC application in the next day or two - I'll link it in this thread once it's done.

oursomatic
Posts: 18
Joined: Mon Mar 09, 2020 2:19 pm

Re: ET10 analog servo-driver

Post by oursomatic »

No that did not help to flip wire or reverse DAC
same result with PID infinit error
and i have no Z index counting

oursomatic
Posts: 18
Joined: Mon Mar 09, 2020 2:19 pm

Re: ET10 analog servo-driver

Post by oursomatic »

Oh !!!!
it was the Analog outuput ! i flip the +/-
I have reverse the wire and it seem to react as it should.
I dont understand because i have try to reverse the motor direction from the software but its was not enougth......

oursomatic
Posts: 18
Joined: Mon Mar 09, 2020 2:19 pm

Re: ET10 analog servo-driver

Post by oursomatic »

Something i have noticed.

MOTION tab:
If i change the value "Speed" and "acceleration" i must CLOSE and RESTART myCNC to notice the change.
---------------------------------------------------------------------------------------------------------------------------------------------------

Can you give me explanation about acceleration value : ( value // min // max // step )
what is the relation between acceleration and feed / jog /rapid / speed

---------------------------------------------------------------------------------------------------------------------------------------------------

At this moment i am trying to tune X axis with 50 mm jog mouvement with the use of KP / KI but i would like to understand the Accelearation strategy of myCNC to perfect it at different speed ,feed and distance.

Thk

ivan
Posts: 278
Joined: Tue Apr 16, 2019 5:30 pm
Location: Ottawa, Canada

Re: ET10 analog servo-driver

Post by ivan »

Glad to hear the problem is fixed.

We have also uploaded a video with the setup process described in a little more detail, should you need it in the future:


youtu.be/x1eIrpvLecY

As for your questions: min/max specify the range for each global variable in the myCNC software (the full list of our Global Variables is available here: http://docs.pv-automation.com/mycnc/global_variables)

Those min/max values are typically set up one during the machine setup, and are not accessed by the operator. The acceleration itself is changed through the User Settings, and it should not be necessary to reload the system after changing the acceleration value:

Image

Post Reply