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Author Topic: Controlling BLDC drive with PWM or modbus??  (Read 807 times)

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Controlling BLDC drive with PWM or modbus??
« on: June 22, 2024, 09:32:49 PM »
I recently purchase a Ican BLDH1500RA 1500w driver to replace the burnt out BLDC spindle control board on my Syil X4.
I double checked the motor's Hall drive table to make sure all my leads were labeled according to convention UVW and Ha Hb Hc 5v & common. (they were)
Here's a link to the 7 page description of how BLDC motors work, and how to determine the proper lead configuration -  https://www.haydonkerkpittman.com/learningzone/whitepapers/connecting-brushless-dc-motors-to-electronic-controllers Very Useful.

I hooked up my motor to the driver and was able to get it to work. It turns on with enable, runs in forward and reverse.
However, the speed doesn't seem to be the 6000rpm max I need.
I was able to set the pole setting with micro switches.
However, I think I need to read and write thru the modbus 485 port to check parameters and change them as needed.
I could also attempt to directly control the spindle through modbus, although PWM and relay control should work fine.
Is it worth trying to run the controller with modbus, or should I just use it enough to set the parameters?

I have an older windows machine running mach 3 with win7.
I assume the serial port would be the DB7 port?
So to hook it up, I would need an adapter cable from DB7 to RS45 which I could make according to pin conventions. Is this correct?

In Mach3, I would have to enable modbus, configure communications settings and test.
Then I believe I would set range of registers to read or write, correct?
For simple parameter changes, it looks like I could read parameters,  change as needed, then write back to driver, correct?
Or do I need an actual modbus program to do so?

For actual modbus control, it seems like I need to use a brain?

Alternatively, I would make a direct connection to the applicable control pins on the parallel cable and bypass the 5 axis board.
All my axis motors work fine, but the spindle controller blew. I'm not sure what kind of output I'm getting from the board, and I don't think it has a relay for spindle control.
Photo of my 5 axis board attached, if anyone recognizes it...
So my output pins on the parallel port would be 5VDC for relay control, right?
Would the PWM spindle control signal be found directly on the specified PWM pin?
Or is the 0-10vdc PWM signal originally used generated on the 5-axis board from some different input from the parallel port pin?
I also need 0-5vdc max PWM for the driver. I'm thinking I could set the max speed to double, but limit PWM to 50% max to get it to work?

If anyone can help give me some direction it would be most appreciated.
Thank you,

Re: Controlling BLDC drive with PWM or modbus??
« Reply #1 on: June 22, 2024, 09:37:41 PM »
photo of 5 axis board
« Last Edit: June 23, 2024, 03:58:32 AM by Tweakie.CNC »