Huanyang VFD inverter modbus base frequency

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11 Jun 2017 20:12 #94413 by Handy8000
First off, thanks to all the devs for the great free software.

I have one Huanyang VFD and connect it to two machines (NOT at the same time).
The motors on the machines have different settings for voltage and base frequency etc.
I can setup and control the inverter from both machines ok using different Linuxcnc setups.

The problem I have is to change the base frequency manually using the VFD buttons (PD04), because the base frequency setting was removed from the hy_vfd command in Linuxcnc.

Can this function be added back in and does anyone know another method (for now) to configure the base frequency via rs485?

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13 Jun 2017 23:01 #94484 by andypugh
This is the commit that removed it:
github.com/LinuxCNC/linuxcnc/commit/b392...183db165113a054a9a23
It looks like the driver never did anything with the data other than make a pin for it.

What does that setting do? (I have a HY VFD, and I have looked in the manual, and it isn't clear)
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15 Jun 2017 20:55 #94557 by Handy8000
Thanks for the link.

Yes, I agree the manual isnt clear.

The manual i have states "This parameter must be set according to the rated frequency of operating voltage on the motor's nameplate. Under normal conditions do not change the set value of base frequency at will . If it is
equipped with a special motor this value should be set properly according to the characteristic s o f
the motor's parameters. Otherwise it may cause the damage to the equipment."

The base frequency is normally the inverters continuous maximum frequency that the rated torque is generated.

I have to change PD004 between 50 & 400 hz depending on what motor i'm running using the panel buttons.
If i don't set the value correctly for that motor it won't run when a gcode m3 is commanded.
Its not the end of the world to do it manually, but i think it would been nice to have the full command set available via rs485.

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16 Jun 2017 16:11 #94594 by seb_kuzminsky
Thanks for reporting this missing feature from the hy_vfd driver.

Do you set PD004 Base Frequency and PD005 Max Frequency to the same value, or are they different?

My reading of the manual suggests they should both be set to the motor's operating (max) frequency, but I'm not sure.

If they're the same, then I'll just make the driver write the --max-frequency value to both PD005 and PD004 (it currently writes it to just PD005). If they're different I'll add a new --base-frequency command-line argument. Seem reasonable?

I'll also add a blurb to the manpage, what do you think it should say about PD004?

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16 Jun 2017 16:54 #94599 by Todd Zuercher
No they aren't the same. The max freq, will set a frequency limit. Base frequency sets the motors name plate rating, (running at higher frequencies will use field weakening.)

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16 Jun 2017 17:22 #94604 by seb_kuzminsky
So the VFD base frequency is set to the motor's rated frequency as indicated on the motor's name plate.

What do you set the VFD's max frequency to?

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16 Jun 2017 18:30 #94616 by Todd Zuercher
To what ever frequency you want as a limit. (Which may or may not be the motors rated freq.)

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16 Jun 2017 19:42 #94621 by Handy8000
@Seb I think for completeness it would be good to set PD004 independently, although most people will probably set PD004 & PD005 to the same value.
The base frequency and voltage parameters are used by the vfd to set a ratio according to a set pattern in the firmware which will produce the rated torque and motor flux. Its possible to use a motor outside its voltage and frequecy parameter set for different torque requirements if you have the ability to "tune" these values.

I also noticed that PD143 number of motor poles is also missing, which would be need to ensure the correct speed of a motor.

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16 Jun 2017 19:59 #94625 by seb_kuzminsky
I added --base-freq and --motor-poles in a test branch named "2.7-hy-vfd-base-freq". I no longer have a Huanyang VFD to test this with, so please test it and let me know if it works, and if it does what you expect.

To test it you can either clone the git repo (at git.linuxcnc.org or at github.com/linuxcnc) and build the branch for run-in-place, or you can wait for the buildbot to build a debian package for you. Since these new hy-vfd features are on an experimental branch, the debs have to be downloaded and installed manually from our "scratch" archive. Let me know if you want help with either of these approaches.
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16 Jun 2017 20:29 #94626 by Handy8000
@Seb Thank you.

I'll try to test this early next week as i'm not at my workshop just now.

I've not tried either run-in-place or installed manually. I'll follow the instructions at linuxcnc.org/docs/devel/html/code/building-linuxcnc.html and see how it goes. :)

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