Tuning and Calibrating Spindle Speed with a VFD (inverter)

Moderator: cnckeith

martyscncgarage
Posts: 9915
Joined: Tue Mar 28, 2017 12:01 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: Yes
CPU10 or CPU7: Yes
Location: Mesa, AZ

Tuning and Calibrating Spindle Speed with a VFD (inverter)

Post by martyscncgarage »

Posted by CNCKeith:

The Acorn outputs 0-10 vdc. 0 vdc = 0 RPM, 10 VDC = max rpm that you choose.

if you set max RPM of 3000

then

M3 S1500 yields 5 VDC on the analog output terminals

M3 S3000 yields 10 VDC on the analog output terminals

M3 S1000 yields 3.33 VDC on the analog output terminals etc...etc..

its up to YOU to set up the inverter (VFD) so that the inverter (VFD) puts out the correct HZ (or DC volts, if using a DC spindle motor) so that 3.33 volts = 1000 RPM, 5 vdc = 1500 rpm etc..

The Encoder allows CNC12 to display actual spindle speed so you can use the encoder to setup the inverter (VFD) properly.
The Encoder gives positional feedback to CNC12 so for example... using G98 on a Lathe the FEEDRATE of the X and Z axis will increase or decrease as necessary to keep the tool chip load the same as the spindle speed changes... or as another example to make good threads etc..

here is how to "tune" the VFD for exact rpm functionality.

1. Enter in the desired maximum spindle speed in the Wizard, write settings to CNC config.
2. Following the instructions in the inverter manual and set the inverter maximum frequency to 120hz.
3. Using the Virtual Control Panel switch to MANUAL SPINDLE MODE and turn the SPINDLE Speed OVERRIDE all the way down.
4. Turn the spindle on CW and make sure it is turning the correct direction. If it is turning the wrong direction correct this by turning off power and swapping 2 legs of the 3 phase cable between the inverter and the motor.
5. Repeat step 3 and 4.
6. Monitor the actual spindle speed on the screen and slowly increase the SPINDLE OVERRIDE until the correct maximum spindle speed is reached. If the maximum speed cannot be reached turn the spindle off and restart at step 2 with a higher maximum frequency.
7. Write down the actual frequency that the inverter is outputting (from the control panel on the front inverter) and then turn off the spindle.
8. Then following the instructions in the inverter manual set the inverter maximum frequency to the frequency in step recorded in step 7.
9. Using the VCP turn on AUTO SPINDLE MODE; and with the Spindle speed OVERRIDE at 100%, in MDI turn on the spindle at 640 RPM (use this command “M3 S640”) Now with the spindle running. Adjust the maximum frequency of the VFD so the actual spindle speed is within 1 rpm of 640 RPM.
10. Spot check the spindle speed across the full speed range commanded vs. acutal reported by the spindle encoder.
11. It is more critical for the spindle speed to be exact at lower speeds and it is normal for the actual spindle speed to be correct at low speeds and up to 50 rpm slower at max rpm then the commanded speed.
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ


Chaz
Posts: 466
Joined: Thu Feb 08, 2018 7:57 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No

Re: Tuning VFD Spindle Speed

Post by Chaz »

Can anyone using a standard HY VFD tell which which parameters they are adjusting for maxmimum please? Is it Parameter 005?

I understand the relationship between this, what we are trying to do and Parameter 144 (Motor rated speed) however I cannot get it to run at 640 rpm, I get max 2060 as expected, I get 653 when I asked for 640. Adjusting max to 51.82 (which should make the speed correct) doesnt make a difference, perhaps there is another parameter overriding this?

Thanks


Dave_C
Posts: 669
Joined: Wed Nov 15, 2017 8:25 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Springfield, MO. USA
Contact:

Re: Tuning VFD Spindle Speed

Post by Dave_C »

CHAZ,

Getting drives to ramp from 0-10vdc and hit every number on the high rpm, middle rpm range and lower rpm range is usually not going to happen!

There are different ways to get 640 to be 640. Keith's way will work for some brands of drives and not for others. For example, the GS2 that I have does not allow you to set "Max HZ" as a setting. Instead it ask you to set "max motor speed" which in turn determines the "max HZ". Most of us want to get the most speed we can so we need to know how fast the motor can actually go and not come apart!

So depending on what speed your motor is safe to run at, you can arrive at this one of two ways. Let's start with Keith's way and set max HZ by first determining how fast you can actually turn your motor. (you need to know, is it rated for this speed?)

(1750 x 2 is 3500 RPM) or (60 HZ x 2 is 120 HZ) (either way will work) Set which ever way works for your VFD and leave it alone!

You don't have to use the wizard as it requires powering up and down the Acorn each time. I just go to the control, hit setup and change the Max RPM number there. (No need to know the Para #, just go to setup and then to control)

If you entered 3500 as the max speed in the control and you then try to hit 640 RPM by entering M3 S640 in MDI, but you get some other speed, just go back to the control and change the max RPM up or down until you get 640 RPM. That is all you have to do!

The short of it is you are changing the "Span" of the 0-10vdc from one range to another until your 640 rpm is 640. You'll never track 100% through the speed range as all my drives seem to get off more on the high end than on the low end.

Now if it is critical to know what your actuall top speed is, say for G50 speed setting, then just put the spindle in manmual mode and ramp it all the way up using the + key until it won't go any faster. That is your top speed. However, don't enter this in the Control as the max speed or you will have to start all over to get the 640 speed you were after.

I set up my mill and my lathe using this method and they both give me correct RPM +/- 1 RPM when I ask for 640 RPM. (also verified with a good photo tach)

Dave C.
Grizzly G0678 Mill ,CNC conversion with Acorn. G4004G Lathe, Mach 3 conversion to Acorn.


Chaz
Posts: 466
Joined: Thu Feb 08, 2018 7:57 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No

Re: Tuning VFD Spindle Speed

Post by Chaz »

Dave_C wrote: Sat Jul 14, 2018 3:21 pm CHAZ,

Getting drives to ramp from 0-10vdc and hit every number on the high rpm, middle rpm range and lower rpm range is usually not going to happen!

There are different ways to get 640 to be 640. Keith's way will work for some brands of drives and not for others. For example, the GS2 that I have does not allow you to set "Max HZ" as a setting. Instead it ask you to set "max motor speed" which in turn determines the "max HZ". Most of us want to get the most speed we can so we need to know how fast the motor can actually go and not come apart!

So depending on what speed your motor is safe to run at, you can arrive at this one of two ways. Let's start with Keith's way and set max HZ by first determining how fast you can actually turn your motor. (you need to know, is it rated for this speed?)

(1750 x 2 is 3500 RPM) or (60 HZ x 2 is 120 HZ) (either way will work) Set which ever way works for your VFD and leave it alone!

You don't have to use the wizard as it requires powering up and down the Acorn each time. I just go to the control, hit setup and change the Max RPM number there. (No need to know the Para #, just go to setup and then to control)

If you entered 3500 as the max speed in the control and you then try to hit 640 RPM by entering M3 S640 in MDI, but you get some other speed, just go back to the control and change the max RPM up or down until you get 640 RPM. That is all you have to do!

The short of it is you are changing the "Span" of the 0-10vdc from one range to another until your 640 rpm is 640. You'll never track 100% through the speed range as all my drives seem to get off more on the high end than on the low end.

Now if it is critical to know what your actuall top speed is, say for G50 speed setting, then just put the spindle in manmual mode and ramp it all the way up using the + key until it won't go any faster. That is your top speed. However, don't enter this in the Control as the max speed or you will have to start all over to get the 640 speed you were after.

I set up my mill and my lathe using this method and they both give me correct RPM +/- 1 RPM when I ask for 640 RPM. (also verified with a good photo tach)

Dave C.
Thanks, ill try that. So in summary, you way is to change the ratio slightly by amending the top speed set via the Acorn Parameters?


Dave_C
Posts: 669
Joined: Wed Nov 15, 2017 8:25 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Springfield, MO. USA
Contact:

Re: Tuning VFD Spindle Speed

Post by Dave_C »

So in summary, you way is to change the ratio slightly by amending the top speed set via the Acorn Parameters?
YUP! :P

Either way, you'll most likely not hit your top speed exactly as set in Acorn, but you can hit your top speed for the motor. IE: Motor set for 3400 RPM but Acorn control max speed might be 3450 or higher in order to get 640 to be 640.

My reason for doing it this way is to get the max motor speed out of the motor and then adjust the span (top end) in the control.

So F1 for setup, then Hit Config, then Hit control. Three steps, set the max speed and adjust as necessary until S640 gives you 640/641 (whatever it takes).

Works for me,

Dave C.
Grizzly G0678 Mill ,CNC conversion with Acorn. G4004G Lathe, Mach 3 conversion to Acorn.


Chaz
Posts: 466
Joined: Thu Feb 08, 2018 7:57 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No

Re: Tuning VFD Spindle Speed

Post by Chaz »

Thanks, that works. Same principle. Its out at 320 RPM but not too bad.


Dave_C
Posts: 669
Joined: Wed Nov 15, 2017 8:25 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
Location: Springfield, MO. USA
Contact:

Re: Tuning VFD Spindle Speed

Post by Dave_C »

Thanks, that works. Same principle. Its out at 320 RPM but not too bad.
Yup, not uncommon to be off a little on both the high end and the low, more so on the high end it seems. It is difficult to get drives to track 100% but some can be made to do so if they have parameters to set the gain ratio and also have an offset feature. Those features tend to cause more trouble than help for people newer to setting up drives.

Glad it worked for you though,

Dave C.
Grizzly G0678 Mill ,CNC conversion with Acorn. G4004G Lathe, Mach 3 conversion to Acorn.


cnckeith
Posts: 7641
Joined: Wed Mar 03, 2010 4:23 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
CNC Control System Serial Number: none
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: Yes
Contact:

Re: Tuning and Calibrating Spindle Speed with a VFD (inverter)

Post by cnckeith »

Acorn VFD calibration how to documents..

https://www.centroidcnc.com/centroid_di ... ds/304.pdf
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html


cnckeith
Posts: 7641
Joined: Wed Mar 03, 2010 4:23 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
CNC Control System Serial Number: none
DC3IOB: Yes
CNC11: Yes
CPU10 or CPU7: Yes
Contact:

Re: Tuning and Calibrating Spindle Speed with a VFD (inverter)

Post by cnckeith »

related excellent videos by marty are here.
https://www.youtube.com/playlist?list=P ... Z2gLwPN8gt
see the Videos going over the VFD setup.
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html


rodgross901
Posts: 1
Joined: Tue Jan 14, 2020 6:11 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: N/A N/A
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No

Re: Tuning and Calibrating Spindle Speed with a VFD (inverter)

Post by rodgross901 »

Hello All:

This topic has help me understand what I need to do, but before I do I would like some information. I am running a Huanyang HY02D211B VFD, and a water cooled 24k 400HZ spindle, powered by 110 outlet. I don't understand the parameters fully, if someone could elaborate as to which parameter I tune to get the correct RPM's, I would be most appreciative. This VFD has the following parameters. P3 main freq, P4 base freq, P5 max operating freq, P72 higher analog freq, & P73 Lower analog freq. I listed what I have my parameters set to, I learned these from some YouTube videos, as well as what RPM's I'm seeing, and my report is attached. Thanks in advance.

P3 400
P4 400
P5 400
P72 400
P73 10 (the video I watched stated to set a lower allowed RPM with this parameter)

When I ask for the following RPM's in CNC12 this is what I get on the VFD box:
1,000 I get 1,800@30HZ
5,000 I get 5,700@95HZ
10,000 I get 10,662@178HZ
15,000 I get 15,646@260HZ
20,000 I get 20,653@344HZ
Attachments
report_780473989334-1008192546_2020-01-14_18-21-53.zip
(290.14 KiB) Downloaded 364 times


Post Reply