The workings of a CNC Control ?

[klrskies]

If I'm asking in the wrong place please re-direct me.

I modify automotive eprom programs for tuneing as a hobby, and I wonder about how the control system of my prototrak EDGE 3 conversational control is configured...it has DOS, does it use an eprom for program storage? Is the main program on a chip? I'd like to know something about how it's configured.

Ken

[vger]

Ken,
I'm not familiar with that controler specificly, but I did look up the programers manual on it. Since it has a floppy disk, it would have a DOS system built in. I would guess there is either a CPU or Microcontroler chip running the unit. You might open the unit up, look up the numbers on the chips and get a better idea of what it is using for storage.

Steve

[klrskies]

Your correct in that it has a Floppy Drive, and it must be installed as the start-up files are on a floppy. As the operating system loads as see references to "386" several times so I'm assuming it's a 386 CPU. It takes considerable time time to read a program file into the memory, and as the control is so small, I wonder if its an eprom. Only one program can be stored internally at a time.

Would it be likely the for machine operating program, (not the part program) for the 386 processor to be stored on a seperate chip?

Wondering... Could another operating chip from a similar but more powerful programming program be copied and installed if they both use the same cpu?

I know, a strange question....

regards,
Ken

[vger]

Ken,

If it is a 386 processor, then there will be an EPROM most likely, but it will only have the Basic system used to start up the floppy and read the machine operating program into RAM. I seriously doubt you would be able to swap out the EPROM with any other system. If you are thinking of upgrading to something a little more current, you may be able to use the motor drivers and encoders and tie them to a BOB and run the machine using MACH3 or something similar running on a standard PC.

Steve

[klrskies]

What's a BOB?

Yes, it's a conversational, 2.5D control that neeeds replaced with 3d inexpensively. Drives are attached to the motors.

regards,
Ken

[vger]

Ken,

A BOB is an abreviation for "Break Out Board". There are lots of different ones out there. It would connect from the parallel printer port(s) on a computer to the motor drives, encoders, spindle control, coolant control, etc.
Here it just one of the many:
http://campbelldesigns.net/breakout-board.php
Is the machine servo driven? or stepper motor driven?
That will make a difference as to what interface (BOB etc) you would need.
Servo drives most generally accept + and - 10 Volts analog to drive them. Stepper drives generally accept logic level signals.
These guys have drives that are very well thought of.
http://www.geckodrive.com/

There are lots of options, most will depend on the motors on your machine.

I'll be out of pocket till Monday. Check out the DIY sections of the forum, lots of good info there.

Steve

[klrskies]

It's servo driven..no central driver, yes +10~-10volt, and the drives are on each servo motor. Estimated cost for a do-it-your-selfer if no drives or motors need to be replaced? Thanks for your help.

regards,
Ken

[Al_The_Man]

If it is not a software driven controller, not, by the sound of it, I would imagine you have a motion card of some kind.
Galil is one example, also EMC uses a slot based motion card also, these all control by ±10vdc analogue and use encoder feedback to the card for PID control.
Check for a motion card in a slot.
Something has to control the motion profile and servo PID loop.
Al.

[klrskies]

I haven't opened the control yet, but he control is about the size of a DRO unit and hangs off the side of the machine the same way a a DRO. The 3 cables to the drives, mounted directly on the servomotors, plug into the back of the control.

I'll need to open it up to see what it has inside. must be pretty compact though.

Assuming it may be possible to go to an aftermarket, 3-axis, PC based control and use as much of the old system as possible...drives and servo motors, how difficult is it to set up everything? Servo calibration required? Lead screw Error compensation? Electronics adjustments? Are the control vendors helpful?
regards,
Ken

[Al_The_Man]

This all depends on what documentation you have at present, wiring schematics etc.
Otherwise it is usually a case of 'reverse engineering' everything by tracing and identifying wiring/connections.
If anyone here has experience either with the control or retrofitting it, you will be ahead of the game.
The fact you mention 386, it is most likely PC based but probabally ISA bus.
Which limits using the card again.
Mach has a plug in for a Galil card but not any of the Legacy ISA versions.
Al.

[klrskies]

Thanks for your help Al. Without schematics and my limited knowledge at this time, it would seem best for a noob like me to find a replacement 3D control system that is well supported by the CNC community and the manufacturer. It needs to be sturdy, durable and well though out with a good interface...from a supplier who'll help me sort out what will work with my drives. I have much to learn!
regards,
Ken

[vger]

Ken,

Here is a thread that may be of help:
http://www.cnczone.com/forums/showthread.php?t=74532

Just one option of the many.

Steve