New Machine Build- OPEN-SOURCE 6A Bipolar Stepper Driver Idea

[joprinz]

I'm working on my second CNC Project. The first Project was a cnc router which had 2.7Nm Steppers rated 3V and 2A to drive the axis. So I used PMinMO 's L297/298 based Driver for them. The Drivers work like charm til date.

However for my current project I am using 8.7Nm DPM Steppers (Model# 86SH118-6004A) which are rated at 2.7 V and 6 A. But somehow as of now there seems to be a lack of DIY versions of Bipolar drivers above 3A. So I Intend to make an Open Source DIY 6A Bipolar Stepper Driver as I believe I'm not the only one who might be interested in a Driver above 3A.

For starters I'm thinking of Using the Allegro A3986 with N Channel MOSFETs for powering the Stepper.

Advantages:

1. The Circuit seems to be simple to design and assemble.
2. 2Wire Control (STEP and DIRECTION) interface is Perfect for Direct use in CNC Applications
3. Micro Stepping Possible upto 1/16th Step
4. PWM Current Control
5. > 6A per phase can be attained

Now the Disadvantages I haven't thought of any Yet... So Plz advice if this is the Right course to take...

It would be great if everyone could suggest Ideas/Schematics/ICs or any advice or considerations that can be useful in designing the driver. Even your experiences with High Ampere Drivers could be very Helpful...

Thank You!

Joe!

[martin.c]

Hello,
we designed and built a driver board using the Allegro 3985 controller and IRLZ34N MOSFETs.

The 3985 uses a serial protocol instead of step and direction signals.
The reason why we used this part is to have tunable microstepping and many adjustable driver parameters. Our design is planned as a driver for big telescope mounts so microstepping is absolutely necessary.

Up to now the driver has been tested with 0.0625 Ohms as sense resistors resulting in 4 Amperes. The power supply has 24 Volts.
But I think the driver could feed more especially if we used FETs with a lower resistance. To increase the power further we plan to feed it with 40 Volts.

The whole system is modular consisting of one master CPU board (32bit ARM7) and some driver boards (Atmel AVR). The backplane communication uses the I2C bus.

Regards,
Martin Cibulski

My small microstepping telescope driver with Allegro 3973 (1Ampere)
http://www.martin-cibulski.de/atm/mo...er_4/index.php

[atlab]

joprinz, read this 50 pages:
New Allegro Bipolar Stepper Driver A3986
Regards

[joprinz]

Thanks Martin, Atlab for your inputs. I'm all set to start working on the driver. I'l post updates here once I finish with the Driver design.

[snoopy27]

Originally Posted by joprinz I'm working on my second CNC Project. The first Project was a cnc router which had 2.7Nm Steppers rated 3V and 2A to drive the axis. So I used PMinMO 's L297/298 based Driver for them. The Drivers work like charm til date. However for my current project I am using 8.7Nm DPM Steppers (Model# 86SH118-6004A) which are rated at 2.7 V and 6 A. But somehow as of now there seems to be a lack of DIY versions of Bipolar drivers above 3A. So I Intend to make an Open Source DIY 6A Bipolar Stepper Driver as I believe I'm not the only one who might be interested in a Driver above 3A. For starters I'm thinking of Using the Allegro A3986 with N Channel MOSFETs for powering the Stepper. Advantages: The Circuit seems to be simple to design and assemble. 2Wire Control (STEP and DIRECTION) interface is Perfect for Direct use in CNC Applications Micro Stepping Possible upto 1/16th Step PWM Current Control > 6A per phase can be attained Now the Disadvantages I haven't thought of any Yet... So Plz advice if this is the Right course to take... It would be great if everyone could suggest Ideas/Schematics/ICs or any advice or considerations that can be useful in designing the driver. Even your experiences with High Ampere Drivers could be very Helpful... Thank You! Joe!

Generally aren't you getting into servo territory at this power and speed? The fact that these drives at this amperage aren't readily available, seems to indicate to me that other solutions are perhaps better and more cost effective.

[chinsettawong]

I'm very much looking forward to seeing your design.

Wachara C.