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Want to get information out there that might help somebody. Short version: If you're having trouble with a DMM DYN4 used as a spindle getting "lost phase" errors and not being able to hit the top rated RPM, lowering the gains might help.

Longer version:

My little baby BT30 benchtop mill is set up with a DMM DYN4 servo as the spindle- drive is DYN4-H01, motor is the 1 kW 86M-DHT-A6MK1. I'm using it in position mode with quadrature inputs. I don't have an index pulse on it, so I haven't tried rigid tapping. The spindle is driven with a 28:44 motor:spindle pulley ratio, using GT3 belts.

DMM was very helpful in getting it set up- provided a tuning procedure and debugging help. Great customer service. Despite that, performance was disappointing- notably the "lost phase" errors, which occurred at high speeds (4000 motor RPM and above, or thereabouts) or under anything but light cuts. Checking the drive's diagnostics page, I could also see the "on position" signal getting inconsistent as RPM increased, even under no load.

I figured it needed more gain- not holding position under no load -> needs more gain. That made things worse, if anything. Adjusting the torque constant (current smoothing) and integration gain settings (two things DMM clearly instructed NOT to change) maybe kinda helped a little bit, but still far from what I expected.

I eventually got fed up and decided to try LOWER gains... works great. Totally unintuitive to me. The chatter I was experiencing cutting 304 stainless also seems to have been resolved. I'm still working up to pushing the limits of the machine, but so far I haven't seen anything to indicate those gains will be too low under heavy cuts.

Every machine is probably different, but FWIW IIRC I ended up with a main gain around 20 and a speed gain around 15. IIRC the integration gain is back at 1 and the torque constant at 127 (per DMM recommendations for this application), but I'm not at the machine to check any of those numbers right now.

Hope that helps somebody! Mods feel free to move if this belongs somewhere else.

What is your screen resolution?

I also ordered some Ethercat boards to play around with it, for now I just use regular Ethernet. I will suspend working on it until after chinese new year since I need connectors.
I also hope I can get hands on more Mitsubishi/possibly other machinery in Taiwan.

Chaining up multiple boards with Ethercat seems to be interesting, especially for the peripheral part.

The Zynq is definitely super powerful, I was able to get away with a microcontroller and accurate timings.
But the MDS-B series only needs 3.55ms framing, not 0.222, jitter is around 20ns (while the measured jitter on the Meldas M65 controller is 40-60 ns .. of course all relatively due to my non certified measurement equipment).
My plan is to make it pretty much modular with Ethercat chaining up various modules for certain tasks.
I want to mix my system with different motors than Mitsubishi for 5 axis support.

I have an old DE2 FPGA board (with ethernet), and a couple of LatticeSemi LFE3/5 boards (also with Ethernet) here which I almost wanted to use for it. I think I will just stick with various microcontrollers and small FPGAs if needed to keep it simple in the future.

Finally, got to test drive the pullmax_optima component with closed loop PID, only p set to 5. Left and right side sync nicely, but with loud groaning noise. This machine runs smooth and quiet when I run it open loop. I think what I'm seeing in halscope is a combination of untuned PID and non-linear hydraulics.

chan. 1 pwmgen.04.value = controls left ram servo valve (driven by j3.vel_pid.output)
chan. 2 pwmgen.05.value = controls right ram servo valve (driven by j4.vel_pid.output)
chan. 3 pwmgen.06.value = controls tonnage proportional valve; ultimately comes from a slider on my test gui.
chan. 4,5,6,9 are the discrete spool valve coil power outputs (cr-200 to cr-203)
chan. 7 j3-motor-pos-cmd ultimately comes from a slider on my test gui. This is the input to the pos_pid.command
chan. 8 j3-motor-vel-cmd is signal connecting pos_pid.output => vel_pid.command

I was hoping velocity PID will allow me to skip the low frequency dither these valves like; but now I'm thinking my lack of that dither is what is fighting my PID. I will try lowering the p value first in case 5 is actually too high, next step is adding that low frequency dither, probably via siggen or a custom component.

It should be possible with hm2_modbus,
(as long as the devices sharing a link have the same baud rate)
mesa-modbus only supports one device (per host UART)
 

No, if you set all PID values to 0 in the .ini file, run linuxcnc
and set LinuxCNC into the machine-on state, all PWM values will be 0
and the PWM enables should all be true (at least for the joints enabled in the hal file)

“Also insure the all PWM enables are true, and all PWM values are 0”
Should I define this in HAL?

Great, that's got the sserial and pktuart ports appearing and working, thank you for the quick response.

We have 3x identical modbus cards to communicate with. Using mb2hal it was possible to address each one but I can't see how to do that using mesa_modbus - is there a way to talk to different addresses over a single pktuart port? This may be a question for Andy Pugh...

Is this possible in hm2-modbus?

OK that looks good.

The next test is to set all PID pins to 0 (P,I,D,FF0,FF1,FF2) in the ini file
and start LinuxCNC, then enable motion, at this point, PWM should be enabled on all axis
but the PWM value should be 0 on all axis. Again measure all the Analog outputs.

Also insure the all PWM enables are true, and all PWM values are 0

 (test done with nothing connected to the 7I97T except 5V power and Ethernet)
 

Have a look in syslog "sudo dmesg" and if you find the word EoE that is a problem.
Typically that interferes with the linuxcnc lcec component, which can not handle EoE.

There is a way to read out the eeprom content from the drive, flip a bit and write the eeprom content back.
However, it is much better to compile the ethercat master yourself with eoe disabled.
It has been recommended before in the forum, please search (I don't have it readily available).

See how far that takes you. 

Axis0 11mv
Axis1 9mv
Axis2 10mv
Axis3 9mv
Axis4 10mv
Axis5 9mv

@Kell,
Do not send reports asking for help, you will be banned for doing that again.
-
From your error report:
Can't execute DISPLAY program qtpyvcp
So did you install QtPyVCP as per the howto on their github?

You are welcomed, always.

forum.linuxcnc.org/18-computer/54368-pci...t-of-the-box?start=0

Nkbhvid wrote:

The 6 axis ranges from 9-11mv

The 6'th axis or all 6 axis?