Denford Triac 1988

[jim the fish]

Anyone can give me any help on how to update or replace my axis drive system. I keep having faults on my Y drive which costs a fortune to repair.
Can I replace it with a suitable system (its Bipolar)
Jim the Fish

[Denford Admin]

To get rid of the rack drives you'll need to find a 3- axis (upto 5Amp) stepper drive like the one we now supply on larger micro-stepping machines (I think they are around £200) - this takes step and direction inputs to each axis and has configurable step resolution and current.
(I'd definately suggest going for configurable step resolution as the existing cards may or may not be half-stepping - 200 or 400 steps per motor revolution)
I wouldn't see any point just replacing the Y axis - you might as well do all three.

You'll then possibly need a seperate transfomer / power supply for the new drive

Then you'll need to locate the step and direction signals off the existing drive cards, and somehow tap off them. I'm sure we have a diagram of the 96(?) way connector on the controller card somewhere, and will try to find it if you need it - let us know

[Triac whizz]

If that's a PC version with stepper motors, I'd trash the electronics & rebuild with Geckos and Mach3, Much better

If you've got a tool change then its rather more involved.... (well assuming you want it to work)

[Denford Admin]

rebuild with Geckos and Mach3

Yep - I think the Geckos are pretty good - powerful and cheap drives

Not sure about ditching the control for printer port (? - correct me if I'm wrong) control software though - even though the DOS software is out of date, its still pretty useful, and can be upgraded to windows VR Milling later on - and you will still be able to control all the machine functions like the tool changer.

[Triac whizz]

Yup, Mach3 uses the printer port, it can use 2 actually.

My Triac being Fanuc I don't know how the VR milling links in, but if you want to send me a copy to experiment with.... I'm guessing it just pumps the G-code to the control via serial

So my suggestion would work. You can make toolchangers work with Mach3 but it's not an out of the box solution, you need to write a macro & there are various ones around for a starting point, but unless someones done one for the Triac..

If the step & direction signals are 5v and not 12v as the old PNC stuff then it's easy to replace a drive with another make, just check max current specs and make sure it's TTL compatable. Just look on ebay or google a search.

As Mr. Denford says, you might as well do all three and if his price is correct, that don't seem a bad price for 3 x 5A drives.

One thing though, going from a whole step drive to microstepping the control needs reconfiguring - I presume that can be done?
As it is now 200 pulses move the motor 1 turn but if say it's 10 microsteps that's 2000 pulses for a turn, so everything would be 1/10th scale.

I'd be interested to know if that can be changed

[Denford Admin]

VR Milling v2 talks to the control cards via RS232 at 19200 baud
VR Milling v5 talks to the older cards via RS232 (upto 57600) and the newer cards through USB or RS232

Because the newer cards have more memory - the PC can stream upto 200 moves to it, and keep it topped up - the control card is then left to sort out smooth velocity curves along all the moves in its buffer - this makes a massive increase in 3D contouring speeds.

RE, the 3 axis drive we now use - its capable of 400 (half step), 800, 2000 and 4000 steps per rev.
There are some options that can be put into the *.OPT file to change the number of steps per mm:

Code: Select all

MINT_MFACT 200
SLAVE_MMCONVERT 200
SLAVE_ACCEL 500 (?!)

I'm not 100% if these will work on all versions of MINT 328 firmware, or all DOS applications - it looks like the later DOS machines needed to have configurable steps per mm, so I'm guessing only the latest software will support it.
Its worth experimenting before investing in a fixed step drive

[jim the fish]

Hi friends. I have looked at all your suggestions and it appears the Geckos and Mach 3 seems the best way to go. Where do I get them from and how much will it cost to do the complete conversion.

Thanks everyone for your help.

Jim

[Denford Admin]

If you're in the UK then try here for the Gecko drives:

http://www.cnc.yertiz.com/
(he's very helpful and knows what he is talking about - he may also recommend other control cards and software such as DeskCNC)


Come back to us though, if the project is going to cost you more than £1000