Need Help!- Mach3 ---> Brushless ESC interface with arduino?

[skmetal7]

Problem: Control a brushless ESC through Mach3

Idea: Program an Arduino microprocessor to convert mach3's PWM spindle output to a brushless ESC's 1-2ms input signal. A brushless ESC needs a 1-2ms on time every 20ms.

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Also have the Arduino ramp up from zero to the set speed in mach3.

Conundrum: I don't know how to program

[skmetal7]

kinda getting somewhere with this in this arduino forum: http://www.arduino.cc/cgi-bin/yabb2/...=1226292633/30 (bottom of page)

i guess programming knowledge would go a long way here :/

[bharbour]

A digital solution like a microcontroller would be the most stable, but you could also do this in an FPGA or in straight analog.

BobH

[eSilviu]

I would do ths way:
1. smoth PWM signal from parallel port (Mach controlled) with a RC filter (you will get 0V for 0% PWM and 5V(or 3.3V) for 100% PWM);
2. read this signal with ADC module of any available PIC;
3. compute in PIC the "servo signal" needed to control the brushless ESC.

you will need:
- R+C filter, 5V PICxxFXXX, a filtering 100nF capacitor on the PIC supply, optional LED+R
- maxim 50 code lines, writed in a high level programming language for PIC (I recommend Mikropascal/MikroC/Mikrobasic - free verion is powerfull enough for this application)

[kretov]

Still actual?
I was wondering about the same problem last summer. I haven't managed to find an existing design quickly, so I decided to make the converter myself. The PIC controller was chosen because it was the only MCU type I had a programmer for
The device is very simple. It sonsists of PIC16F629 controller, a capacitor and a LED to indicate its operation.

The converter is connected between any available LPT output pin and ESC. Provided that large speed controls for large brushless motors usually do not have BECs, the ESC's BEC is not used and not connected. The device uses +5V power supply from BOB or PC.
The scheme and PCB layout are simple. I have used my CNC mill to engrave the PCB

The recommended PWM frequency setting for Mach 3 is 350, active is high.
You can see here how it works:

Mach3 to brushless ESC PWM converter - YouTube

Mach3 to brushless ESC PWM converter - YouTube

The firmware file for PIC is in the attachment.

[skmetal7]

This is cool. It kind of sounds like the motor is revving up and down, how stable is the RPM? You could probably put a disk with a hole and an interrupt switch to let mach know the actual speed.

[kretov]

I haven't performed a research of how stable RPMs are, but can say for sure that I haven't noticed any difference in motor's behavior under control of this device and Futaba receiver
I think that for mill RPM sensing is not that important as for lathe, for example. Hovever, supplying RPM measurement is one of my nearest tasks, and it looks rather easy. I will post an updated device once I'll get to it.

[mactec54]

kretov

Thanks for sharing & great job with your design, I know someone that can use this for there spindle control