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Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1344

Posted: 03:12pm 09 May 2014

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G'day Guy's,
Finally got that cnc lathe home last night and unloaded it this morning in my shed. Got straight to playing with it only to smell that magic smoke and found it was coming from the PSU, the joystick showed power supplied but no movement from any of the buttons so it was time to strip it and see what was driving the axis and spindle.

The lathe came with a quick change tool holder with 6 stations and thats going onto my toolroom lathe, also several cutting tools with insert carbide tooling was there including a parting off tool so I'm wrapped.

Now the spindle drive is powered by a:- SEM PM DC Motor 180 volt 2.8 amp (type FDPM30L2)

Both the X and Z axis are powered by servo motors:- (Electro Craft E586-SA) and now I have never dealt with servo's mainly due to not having access to any but never to late to start.

Below is a pic of the old electonics and basically it is just 3 off axis cards and the board on the right is a distribution board. The problem with the lathe is Hercus designed it to be used all from a PC and floppy disk where the software isn't available anymore.

Now once I can learn about these servo motor my plan is use a maximite to drive them and also have a lcd display.

Got a lot to learn and I reckon this will be a fun project.

Cheers Bryan

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1344

Posted: 06:33pm 09 May 2014

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G'day Guy's,
I've taken the Z axis motor out and had a look at the controller card where it looks like only 2 pins on the parallel port connector are used for signalling. Also several pins are ganged together for power and ground so it does look like I may once I decipher the driver board only a clock and PWM will be needed to get the servo going. As far as motor position there is a separate circuit which I'll post tomorrow. Now the board has a H-bridge using 60 amp fets and a L292 stepper chip, there is a 2 pin connector that goes back from the servo.

So as far as the reverse enginearing goes in theory this will work and with having the servo out I can use that ikalogic 4 channel analyzer to look at the position sensor and hopefully get that worked out.

Got visitors today so my fun has ended and only a short time in the morning due to mums day but I'm getting there.

Cheers Bryan

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 04:35am 10 May 2014

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Quote and had a look at the controller card where it looks like only 2 pins on the parallel port connector are used for signalling.

On average there will be a step pin and a direction pin, the direction pin tells the card which direction to step the motor, the step pin will advance the motor 1 step with each hi - lo transition of the pin, all very basic standard stuff in the average CNC control systems ........ but perhaps you have a strange system outside the normal, although i doubt it, and think any interface would suit your system.

Servo motors just have an encoder in the back end to send position data back to the controller, so rather than count steps, the software needs to count pulses from the encoder to know its step position.

Pete.

Sometimes it just works

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