Spindle Speed Question - PROBLEM SOLVED

All things related to the Centroid Acorn CNC Controller

Moderator: cnckeith

Post Reply
cncman172
Posts: 254
Joined: Thu Nov 02, 2017 4:07 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 985DAD429EE9-0926170118
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Westerville, Ohio

Spindle Speed Question - PROBLEM SOLVED

Post by cncman172 »

Hey Gang,

Quick question, I hooked up my Huanyang spindle the the Acorn and set a few parameters and it works. I can turn it on and issue a command like M3 S9000 and it starts right up. However, I can run a gcode file and hear the spindle changing speeds. I wondered if this was something set wrong in the Acorn, but looked under spindle and it shows the highest spindle speed is 24000. I then decided to see if the VFD was causing these changes or if it was something else. When I connect a Fluke digital multi meter to the the analog output between Analog Ground and Analog Out I can see the voltage changing by .3V to maybe .4V and it goes up and down.

Do I perhaps have constant surfacing enabled or something. Normally on a router you do not want the spindle motor changing speeds in this manner.

Thanks

Russ
Last edited by cncman172 on Thu Dec 14, 2017 5:47 pm, edited 1 time in total.
Centroid_Tech
Posts: 286
Joined: Thu Mar 18, 2010 2:24 pm

Re: Spindle Speed Question

Post by Centroid_Tech »

Please send us a current report from your system. Your spindle speed shouldn't be changing speeds unless you are running Constant Surface Speed in the Lathe software. Disconnect the analog signals to the inverter and command a speed. Do you see that voltage oscillating?
When requesting support, please ALWAYS post a current report. Find out how to take a report from your Acorn, CNC11 or CNC10 system here: https://www.youtube.com/watch?v=Ecvg0VJp1oQ.

If your question is PLC, Macro or program related, please also post a copy of the program or macro as well.

Without the above information we may not be able to help and/or reply until the required information is posted..
cncman172
Posts: 254
Joined: Thu Nov 02, 2017 4:07 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 985DAD429EE9-0926170118
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Westerville, Ohio

Re: Spindle Speed Question

Post by cncman172 »

I will run the test and provide the report. It is possible the wire going from the Acorn to VFD is too small a gauge wire. I used a shielded ethernet wire which is about seven feet long. I will verify if the analog output changes without load.

Russ
cncman172
Posts: 254
Joined: Thu Nov 02, 2017 4:07 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 985DAD429EE9-0926170118
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Westerville, Ohio

Re: Spindle Speed Question

Post by cncman172 »

I ran the test and the same gcode file with the meter attached to the analog out is rock solid except when the gcode commands a higher speed. Does this suggest the wire size is too small. I can get a larger cable the Ethernet wires are tiny probably 22 awg maybe even 24 awg.

Russ

report_985DAD429EE9-0926170118_2017-12-11_20-07-24.zip
(152.47 KiB) Downloaded 114 times
Centroid_Tech
Posts: 286
Joined: Thu Mar 18, 2010 2:24 pm

Re: Spindle Speed Question

Post by Centroid_Tech »

I doubt that it has anything to do with the wire sizes but those signal wires should be a minimum of 22AWG. When you ran your test, were the analog signal wires disconnected from the VFD? Were the probe meters directly screwed onto the terminals of the ACORN board? I'm not sure what "higher speed" really is. Please clarify.
When requesting support, please ALWAYS post a current report. Find out how to take a report from your Acorn, CNC11 or CNC10 system here: https://www.youtube.com/watch?v=Ecvg0VJp1oQ.

If your question is PLC, Macro or program related, please also post a copy of the program or macro as well.

Without the above information we may not be able to help and/or reply until the required information is posted..
cncman172
Posts: 254
Joined: Thu Nov 02, 2017 4:07 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 985DAD429EE9-0926170118
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Westerville, Ohio

Re: Spindle Speed Question

Post by cncman172 »

When I ran my test initially the wires ran directly from the Acorn to the VFD in a shielded Ethernet cable.

For the second test I just disconnected the analog output from the Acorn and touched the two meter lead directly to the Acorn analog output pins. The voltage stayed constant at the speed requested no fluctuation at all.

On the higher speed comment I was just saying the DAC went to the correct voltage for the speed requested with no load attached. 12,000 RPM would measure 5v and 24,000 would measure 10v.

I am traveling today but will change the cable size tomorrow to see if it impacts the results.

Russ
Centroid_Tech
Posts: 286
Joined: Thu Mar 18, 2010 2:24 pm

Re: Spindle Speed Question

Post by Centroid_Tech »

With the wires disconnected, we now know that the issue is not with the ACORN. It could be an issue with the cable. It could also be an issue with the VFD. Please verify that the VFD is setup to accept a voltage as the control signal. I know that some can either accept a voltage or a current as the control signal and they typically have a jumper on the VFD. Another thing that would cause that behavior would be a grounding issue. Even though you're using a shielded Ethernet cable, there may be a sneak path on the VFD that is introducing electrical noise at higher spindle speeds.
When requesting support, please ALWAYS post a current report. Find out how to take a report from your Acorn, CNC11 or CNC10 system here: https://www.youtube.com/watch?v=Ecvg0VJp1oQ.

If your question is PLC, Macro or program related, please also post a copy of the program or macro as well.

Without the above information we may not be able to help and/or reply until the required information is posted..
cncman172
Posts: 254
Joined: Thu Nov 02, 2017 4:07 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 985DAD429EE9-0926170118
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Westerville, Ohio

Re: Spindle Speed Question

Post by cncman172 »

The VFD does accept the voltage input the current pin is not connected. It almost works perfect but spindle speed moves around probably by +- 2%.

Good suggestion on the grounding. The VFD is grounded and mounted on an aluminum plate. The shielded cable going to the Acorn is only grounded on the VFD end. I will hook up my scope tomorrow and look for noise.

Thanks

Russ
cncman172
Posts: 254
Joined: Thu Nov 02, 2017 4:07 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 985DAD429EE9-0926170118
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Westerville, Ohio

Re: Spindle Speed Question

Post by cncman172 »

PROBLEM SOLVED

I had used an Ethernet cable that actually had 28 AWG gauge wire. The cable was shielded and that is why I used it for the VFD control signals. Ends up the size worked fine for turning on/off the VFD. The issue was I was getting speed variation on the spindle and you could see it at the terminal of the analog output using a meter. I hung a new wire just for the analog signals no shielding at all and double up the conductors where were 24 AWG. I ran the test doing an air cut with the router and the spindle speed was constant until it switched speed due to gcode command. Another item addressed.


Russ
Post Reply