PKS Digiplan with Mach3

[sweep]

AHH Frustration
Rebuilt the interface board with a 'power take off' for the other pins that are not listed on David's drawing but the problem doesn't seem to be anything do do with these extra pins.
After further tests, it seems that one of the fuses on the X card, and only the X card, keeps blowing.
If I connect the cards to the Triac board as God intended then all the motors come up to power and hold position. If however I connect through the interface board, with or without the extra cable fitted to the main Triac board, the X card fuse blows and none of the motors power up.
I have triple checked my interface board and I do not have any stray earth faults. I have also checked the transistors between collector and 0V (emitter side) and have no reading of resistance (infinite), so whats going on? I am not sure if this is how you test transistors but even if I got a dead short between collector and emittor I should only get a single step signal.
I thought about splicing in a resistor between the 12v signal lines and transistors to match the 1amp fuse rating but I haven't even applied 5v yet to thetransistor base to energise it so the 12v step and direction circuits should be un-made.
I reconnect the 16pin ribbon cable direct to the Triac board and everything is ok.

any suggestions?

...Richard

p.s. um, those Gecko's are looking mighty nice at the moment

[davidimurray]

Hmmm - that sounds like a problem with your wiring / circuit.

When I first setup my system, the drivers were connected to the main control board on terminal block, so all I did was unhook 3 wires, step, dir and ground.

Can you setup a test board in such a way that you can test each axis at a time with the same circuit. i.e I am thinking of a ribbon cable to terminal blocks - most of these will just be passed straight through, but make the step/dir line pass through with bits of cable. Test the machine to see that it all works with step/dir lines all passed through. Now remove the pass through cables for one axis only and put them via your interface circuit board (this will be 1 transistor and resistor on a board) - leave the other 2 axis passed through. Power up and see what happens. Try this for each axis, the other 2 being straight through in the meantime.

If you do it this way you can test each axis indepenantly with a single good bit of electronics - less variables to be wrong.

Note that droppping geckos in will still require a lot of work - and may even need a power supply change (the digiplans take AC striaght from the transformer - geckos need a DC supply)

Also have you considered swapping the X and Y axis cards over, see if the fault follows? BUT whatever you do DON'T swap the Z axis with x or Y. They are different drivers (X and Y are 2 amp, Z is 3 amp!)

Cheers

Dave

[sweep]

I did try something similar to what you were suggesting last night. What I did was simply unplug the ribbon to the drives. I then powered up which energised the motors. I then 'shorted out' the Z step pin on the cable to 0v. Whilst this sounds crude it is exactly what the interface circuits does anyway, but again nothing moved.
I'll draw up a circuit board tonight and go to Maplins tomorrow to get some bits o do what you suggest and tap into one cable at a time.
So much for the 79p per drive you suggested when I first started this project

...Richard

[davidimurray]

Strange

As I say when I did mine I simply unplugged the step/dir and ground and hooked them in. Sounds like it could be something else. Have you checked the enable lines and the estop. Are there diagnostic LED's on the drivers? If so I take it they are reporting no errors?

Is there anything connected to Pin 29 on the header? What about jumper LK4 - is that fitted?

[sweep]

Gotcha

Sorted out my mistake and i've now got movement and direction on all axis.
Problem 1) came about when I did a continuation test between drives motherboard and 16pin ribbon cable. By mistake I connected 24v to 0v ouch! No wonder I kept blowing fuses.
Problem 2) was due to the X,Y, & Z fault pins needing a 12V signal from the main machine borad to the drives board to allow them to run.
The machine feeds 24v from the motherboard into the main machine board where it is regulated to 12v and then, via logic, fed back though the 16pin cables X,Y &Z fault pins, to the drives motherboard enabling drive.
I have attached a couple of pictures of my circuit board. The bottom ribbon cable is feed from the drives motherboard and the top cable is taking 24v to the machine PCB and 12V back. The pins that are needed for this are just linked together between the two scockets on my board.
It is a bit untidy but it does work and has proved I can get movement. Once I have set up Mach3 and driven the axis from the remote computer I will probably build another board and put a regulator on it so removing the need to daisy chain bwtween motherboard and machine board. It will also allow me to move the board outside the Denford machine cabinet.

I will post again when I am running from PC which will hopefully be tonight

...Richard

[Denford Admin]

Good news

Let us know how you get on with Mach - obviously it won't be as good as our software though

[davidimurray]

Congratulations - are you planning to leave the original controls in or will you rip out the old control board and shove the PC etc under the machine?

[sweep]

At the moment I am just going to leave all the original board intact until I have proven Mach3 and used it for a while as at present it is still easy to take a step back and have a standard machine.
In time I will probably strip out the bits I need from the original under-machine drawer and build them into a new enclosure along with break-out board and ModI/O for the toolchanger and spindle speed control.
I think the only thing that wont be used is the main machine PCB as the transformers and contactors can be used. In fact all of the LH side of the elcetrical drawer could be pulled out in one lump if it wasn't for the fact that its sub-frame was welded to the drawer.
The other thing that I have been thinking about is to make a new cabinet with coolant tray and drain, with a pump and tank underneath. I am a bit wary about having all the electronics undernreath the cutting area, as they are now, where they can possibly get wet etc.
The Triac does seem to have quite a big footprint for a small table machine, particularly with the two ATC boxes on the back. I don't suppose this was a problem with the original machine, but now I have to accomodate a PC, keyboard, and electrical enclosure the area it takes is getting out of hand. The other thing is that all the original controls wont be used in the full Mach3 installation.
Has anyone ever fitted the Triac mechanics onto a new cabinet, or, probably more to the point, seen the need ?

...Richard