Motion Control drivers and motors

[bruce_miranda]

Bruce - how are your drivers wired to the PC? The MDS series are opto-isolated. Unless there is some strange wiring issue a higher output voltage wont make any difference as they are active low drive.

I'm going to give Gary the benefit of the doubt here because he obviously knows his products better than I. So I've bought the only CNC4PC C1G breakboard board that was in stock. Hopefully this will solve my problem. If not then I'm back to the drawing board. Having said that the MSD542 manual does says that its looking for 4-5V for Active High and 0-0.5V for Active Low and since my laptop is giving 3.33V it may not be enought to kick the driver properly

[Lee Roberts]

Maybe you should strip everything back and set one up at a time and see if you can find the problem that way, i noticed kip said somthing about your SW's being set wrong on the other post.

I'v just merged this thread with the other one you started Bruce as they see to be about the same thing, be nice to see a new thread on the conversion of your mill after you hash these issues out.

Lee

[bruce_miranda]

I'll be doing a full write up of my entire set-up once things start working fine because I'm sure that are many like me who are complete novices and everything out there assumes you know something of CNC, plus there are very few UK only people who have a full write-up.

I was a bit too over confident and set-up everything into the box. If with the new BOB things don't start to work well then I'll have no other option but to start again.

[Lee Roberts]

I was a bit too over confident and set-up everything into the box. If with the new BOB things don't start to work well then I'll have no other option but to start again.

Gary has already suggested its an issue with low power laptops didnt he?

I just had an email from Bruce, and it apears that his clock pulse is about 3.3V, and he is using a laptop.

This is most definately the problems, and is actually quite common when a laptop is used.

The solution would be to use either another laptop with higher voltage outputs, or a desktop PC with a parallel port.

Bruce,

Try this and give us your results.
Thanks
Gary

[Gary]

Mot sure about the Bob, but The measured voltage was 3.3V, which is on the border line of working for the optos.
I have found that most support calls that end with the signal voltages being too low were on laptops.

What breakout board is he using? The MDS drivers are optisolated so dont really need a sophisticated BOB and are pretty immune to cross-over noise on the signal lines due to the low impedance 'on' drive. Unless he has a very long cable from PC to BOB or the BOB is a old design with TTL rather than CMOS logic I'd be suprised that the use of a laptop was an issue.

[bruce_miranda]

Mot sure about the Bob, but The measured voltage was 3.3V, which is on the border line of working for the optos.
I have found that most support calls that end with the signal voltages being too low were on laptops.

Don't say that after I've just spent £33 on a BOB! Not to mention having already spent £10 for the previous BOB which won't be used.

I'll update this thread the moment I find something else worth reporting.

Anyone else here using a CNC Fusion kit? I've had alignment issues with the Z axis in particular. Is it right that the entire weight of the Z axis is taken by the collar supplied in your kit? Also why is there so little space made around the LoveJoys? The Orange sticker peeled out on a couple - just shows how close they are to the walls.

[Lee Roberts]

Bruce, post your questions about the f-kit as a new one so people notice it other wise it could go un noticed mate. I'v also sent you a PM about the BOB you no longer will be using.

[Gary]

When we initially talked i presumed you were using our Bob, and this is a straight through bob with no components but two connectors.
What bob are you using?

Don't say that after I've just spent £33 on a BOB! Not to mention having already spent £10 for the previous BOB which won't be used.

I'll update this thread the moment I find something else worth reporting.

Anyone else here using a CNC Fusion kit? I've had alignment issues with the Z axis in particular. Is it right that the entire weight of the Z axis is taken by the collar supplied in your kit? Also why is there so little space made around the LoveJoys? The Orange sticker peeled out on a couple - just shows how close they are to the walls.

[bruce_miranda]

I am using a similar BOB but was half the price and made by a CNC user, the board is milled on a CNC machine itself and comes with 4 PCB stand-offs.

http://www.cncdoctor.co.uk/ParallelP...ard(P.004).pdf

[irving2008]

I am using a similar BOB but was half the price and made by a CNC user, the board is milled on a CNC machine itself and comes with 4 PCB stand-offs.

http://www.cncdoctor.co.uk/ParallelP...ard(P.004).pdf

Bruce. That BOB MUST be used driving the opto's in ACTIVE LOW configuration. Its half the price because it has no active drive components, its just a connector. The PC on its own will not have enough output drive to drive the optos in active high mode. The signals on the MDSxxx are labeled thus Step+, Step- and Dir+, Dir- The - connections need to go to your driving signals and the + connections to a source of +3.3 or +5v power. This can be got off a USB connector, off a spare disc power connector inside the PC or via a cheap 5v regulated wall-wart. See pic.