Acorn does not recognize motor after auto-tuning <clearpath software setup>

[DesertRider]

I have a PM 728-VT with the PM CNC Conversion kit, and Teknic Clearpath motors. The system worked well. I made some mechanical changes to the x axis and auto-tuned the motor. Afterwards, Acorn no longer recognizes the motor. So after turning it on, and homing it, it homes the z and y axes, and then proceeds to the x axis: the display shows change in the position but the motor does not turn.

I can drive the motor from the Teknic MCP software motion generator, with the new configuration, so the motor is not damaged.

If then I reload an old config file unto the motor, Acorn recognizes the motor and drives it appropriately, homes well and responds to WMPG as expected. So both the motor and Acorn work well, nothing is burned out. It's only the new config file does not enable the motor insofar as Acorn is concerned.

I am sure there is very simple reason for this, but I tried it three times with the same result and drives me crazy. I looked at the config files and even compared them side by side in BBEdit and there are of course some positioning and other differences, but how can I make it so that Acorn recognizes the new config file?

I attach the two files -- the one from April 2022 is the one Acorn recognizes just fine, the December 2022 one is not recognized.

Teknic config files.zip

(4.71 KiB) Downloaded 2 times

All help is appreciated.

[Gary Campbell]

Any chance your unworking profile is not set to step and direction?

There is something amiss with your motor profile. If you wish them to be compared and diagnosed you should send them to Teknic support.

FYI, Acorn has no means to "recognize" a motor. It is an open loop system which can only react to an HLFB signal if properly configured. In fact in most cases the Acorn controller has any idea that a motor is actually connected.

[DesertRider]

Here are the configuration files side by side, with the GOOD one on the right and the BAD one on the left. There is a faint blue highlight of the few differences, hopefully visible -- click on the photo for an enlarged version. Thank you all for any help.

[DesertRider]

@teknic_servo any suggestions, please? I suspect there is an easy fix for this from someone who knows these motors well. Thank you.

[DesertRider]

Any chance your unworking profile is not set to step and direction?

There is something amiss with your motor profile. If you wish them to be compared and diagnosed you should send them to Teknic support.

FYI, Acorn has no means to "recognize" a motor. It is an open loop system which can only react to an HLFB signal if properly configured. In fact in most cases the Acorn controller has any idea that a motor is actually connected.

Thank you for the clarification. I do think the problem is exclusively on the Clearpath side -- the new config leaves the motor unresponsive to signals from Acorn.

Any idea what I can do to fix it?

[Richards]

In the ClearPath-MSP program, have you verified that the input format is Step+Direction and not Quadrature? When running from the Acorn, Is the ClearPath motor LED Green or Amber? Green is required.

[DesertRider]

In the ClearPath-MSP program, have you verified that the input format is Step+Direction and not Quadrature? When running from the Acorn, Is the ClearPath motor LED Green or Amber? Green is required.

The light is green.

I did not change anything in the MCp software I am pretty sure it is Step + Direction.

Well, a big setback: the USB cable got pushed sideways by the enclosure and snapped off the female connector. Right now I cannot work on the tuning problem until connection is reestablished. I am going to ask Teknic if they will repair it.

[Richards]

Let's review the procedure to run a SDSK ClearPath from an Acorn. In the Teknic MSP software, the motor must be set to Step+Direction. In the MSP software, the servo can be tested for motion if it is set to Step+Direction or to Quadrature.

Page 29 of the ClearPath User Manual Rev 2.27 shows how to wire the two Enable conductors, the two "A" conductors and the two "B" conductors. The "+" conductor must be connected to +5 to +24VDC. The Acorn will pull the "-" conductor LOW (if you use the H2/H3 connectors). The "A" conductors are used for Direction. The "B" conductors are used for the step or pulse signal. See page 147 of the ClearPath Users Manual. The HLFB conductors can be used to signal the Acorn when a fault occurs but they can be left unconnected for testing purposes IF they are not used on the Acorn to indicate a fault condition. Page 48 explains the MSP settings that can be used with the HLFB signal. Read the Centroidcnc topic in this forum that explains the approved method of connecting a power source and resistor to the signal lines. I tested that method and it works perfectly.

Page 33 shows how to connect a Teknic power supply to the servo.

Page 44 explains the purpose of the Enable conductors. The servo must be enabled before it will respond to step and direction signals.

The Step and Direction signals must be timed properly, but the Acorn handles that automatically.

GREEN LED on the Servo indicates that the servo has been enabled by the Acorn and that it has been connected to a power supply. With a Green LED, the motor is ready to accept Step and Direction signals. A YELLOW LED indicates a problem. See page 124 of the User Manual.

You have a Green LED, so you know that the Enable signal is working and that the motor has power. Even with a broken USB connector you can take the next logical step. Power off the Acorn and switch the Z-axis motor with a motor that is working properly. Power things back up. If the switched motor works on the Z-axis and the original Z-axis motor still does not work on the other axis, then the motor may be at fault. If the switched motor does not work on the Z-axis, then it's time to carefully check all wiring connections. I use an oscilloscope to check the timing and the voltage levels of the step and direction signals.

[DesertRider]

Let's review the procedure to run a SDSK ClearPath from an Acorn. [...]

You have a Green LED, so you know that the Enable signal is working and that the motor has power. Even with a broken USB connector you can take the next logical step. Power off the Acorn and switch the Z-axis motor with a motor that is working properly. Power things back up. If the switched motor works on the Z-axis and the original Z-axis motor still does not work on the other axis, then the motor may be at fault. If the switched motor does not work on the Z-axis, then it's time to carefully check all wiring connections. I use an oscilloscope to check the timing and the voltage levels of the step and direction signals.

Thanks Richards for the thorough reply. I have auto-tuned the system before many times, that's why I have an earlier configuration that works. The problem was the new mechanics needed a new tune, and the system (=the motor) does not respond. When I reload the old config, it works. Baffling!

Now the momentary snag is that during another auto-tune attempt, the cable was caught in the enclosure and snapped the USB female connector off the motor. The auto-tune had not completed, so no there is no configuration on the motor, and it does not respond to Acorn. I cannot reload the old, working config either. So I ordered a new motor, and will try to have this one repaired (and will use it on a fourth axis, or perhaps an ATC in the future, etc). These are two separate issues.

Will report back after I have received and installed the new motor.

Thank you again for the thoughtful reply.