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Thank you very much. Is there anything else that can be damaged down the line? I mean the DAC? 
 

Hi,From few month program SIM (not on the CNC) are stucking before controled movement (not G0). By chance, I have fond that reducing spindle speed unlock the program.
I take a look a the HAL configuration and check some values with HalShow. Starting from spindle-speed-cmd to spindle-at-speed, There is a calculation error between sim_encoder_0.speed input pin and encoder_0.velocity output pin.

Attached a calc file with some values of tested values
Version info : LCNC 2.9.8 Run In Place SIM on LinuxMint 22.3 (6.8.0-117-generic

I just tried increasing D and it seemed to increase the amplitude of the oscillation as I increased the value. 

I also wanted to verify the encoder is working correctly even though it appears to be working correctly in halscope. I hooked it up to an oscilloscope and got a chart I wasn't expecting. Channel A seems to be stopping at 0V on both the rising and following edge. channel B seems correct and bounced between +5V and -5V.

Would this cause any issues with counting on the mesa card?

cbaugher has shared is RP2035 version which used remora-core. A really neat implementation that has both ethernet and spi communication options. Uses PIO for the SPI and hardware QEI (Quadrature Encoder Interface).

github.com/cbaugher/Remora-RP2350-PIO/tree/main

Hard t tell but it does look the the velocity loop is unstabley

Just as a test have you tried adding some D term to the PID?

It was originally set up with a virtual tach signal coming from the Fanuc controller. The original manuals showed a tach voltage of 3V/1000RPM which I should have. I ran the motor on a bench power supply, bypassed the drive, calculated the motor speed with an oscilloscope connected to one of the encoder pins, then measured the output voltage on analogout3. my output seems to be scaled correctly and the voltages match the original drive documentation.

I believe I have the scaling and direction correct, but am wondering if I am running into some type of resonance between the virtual tach and commanded velocity.

Does that seem possible or correct?

Method 34 is using only the Z pulse of the encoder, no homing sensor is needed for this homing method.
The homing sensor is connected to any of the digitals input pins of the drive. It is not assigned by default, i. e. it is configurable.
I just tested homing using a homing sensor with homing method 19. But still, the drive behaves the same way as in the video - starts looking for the sensor at high velocity, when rising edge is triggerred the motors reverse at slow velocity, when falling edge is triggered the motor starts moving quite fast and position deviation errkr is triggered.

Did you connect the origin switch to the servo?
It's usually called the HOME switch.
The VECON manual is really terrible.
It doesn't say anywhere where to connect the limit switches and the origin (home) switch.

@leandrocontarini Could you share the bit files you are using?

The original part was a NE5230, which is now obsolete, a suitable replacement is a THS4281D or a OPA197IDR
 

I achieved some kind of success in homing the servo motors using the CiA402 home component. There is still a problem when the homing is executed in a certain situation. Basically, I am using homing method 34. Then using the halshow I set  the 'request-custom-homing' pin, the homing procedure starts but when the servo find its Z pulse it start moving quite fast. Perhaps it tries to reach a certain position but LinuxCNC reports 'joint 0 amplifier fault' and the servo drive error is 'Position deviation is too large'. You can see videos of what is happening - one video in normal velocity and one in slow motion.  Videos
This behavior of the drives can be observed the the actual position is above 35 000 000 pulses. When the homing is started below this pulse number, the motor finds it Z pulse and the move quite fast to the position where the homing was started.
Attached are the configuration files.

Moved to "QtPyVCP" section.

Did you find anyone to help?
If not, post some pictures here, we are quite good at figuring out things from pictures and videos.
Also some pictures of the insides of control box would help a lot.

www.google.com/search?q=mesa+7c81+raspbe...+site%3Alinuxcnc.org

www.google.com/search?q=Emco+Turn+55+sit...+site%3Alinuxcnc.org