Help with drill-Mill conversion

**Ross77** · 04-08-2009

Opto's if none is found when you fire the circuit up it maybe because they require some voltage

Cheers, I did check the outputs when the onboard processor was controlling the motors and could see the logic highs and lows on the step and dir. pins, but when I tryed to inject a signal in to it my self nothing happened. I was just wondering if anyone knew if the enable pin can completely switch off the chip? as the board is double sided and very crowded it is difficult to see what is going on. (and after the last one went bang , I'm not keen to randomly test points) I was hoping that the enable switch is also controlled by the processor, which would explain why the motors wont work when I try to control them.

They go bang because of excessive current not voltage...usually if upper and lower devices in the bridge are 'on' simultaneously... 40v across .5 ohms = 80A peak, 3200W instantaneously.... your PSU will do that for a few 100uS no problem!

Looks like I must have shorted something whist I was trying to get it to work. Is this driver set up usually Ok?

P.S if you are throwing them away KIP, my bin has plenty of space

**Ross77** · 06-08-2009

I have a good arm...although the bin in Devon is a throw too far for me :D

Fair play, It was worth a try tho eh :naughty: Damm you yorkshiremen....

Im not one to be beaten so had another crack at the control board. Rewired the inputs to the L297, bypassed the output relays and it worked.............:dance:

......Until I turned the Vref pot the wrong way and fryed the output chips AGAIN. So at least I've found something i'm good at. :rofl:

Question time. If all 3 motors are 2 phase, 8 wire and configured in parallel, then why is one of the motors wired differently at the board plug? surley the phases cant change as the motor wouldnt turn...

Hope to make some real progress this weekend. so post some more pics soon

**Ross77** · 06-08-2009

Forgot to ask if anyone knows of a good cuircuit to test stepper drives? I'm looking for an MPG type thingy that dosnt require a pc or mach, but will generate the correct pulse voltages, timings etc for step and direction

Maybe i should post In the drivers section?

Cheers

**irving2008** · 06-08-2009

Originally Posted by Ross77

Forgot to ask if anyone knows of a good cuircuit to test stepper drives? I'm looking for an MPG type thingy that dosnt require a pc or mach, but will generate the correct pulse voltages, timings etc for step and direction

Maybe i should post In the drivers section?

Cheers

Funny you should say that, i was just thinking along those lines...

I'll post it up later...

**irving2008** · 06-08-2009

Originally Posted by Ross77

Forgot to ask if anyone knows of a good cuircuit to test stepper drives? I'm looking for an MPG type thingy that dosnt require a pc or mach, but will generate the correct pulse voltages, timings etc for step and direction

Maybe i should post In the drivers section?

Cheers

Ross, are you saying to exercise the stepper drivers directly without a PC, or to drive the motors without a stepper driver?

**John S** · 06-08-2009

Originally Posted by Kip

I have a good arm...although the bin in Devon is a throw too far for me :D

Tell you what, Nottingham is nearer and I can take them down to Bristol on the 22nd when I go to the show.

Let's shame the bastard :clap:

.

**tribbles** · 10-08-2009

Farnell will charge the first time you use them, I think (that's what happened to a mate of mine [who asked me to order the bits for him instead, since I tend to chuck about £200 a month at them] and my brother).

I'd also put RS in that list - although RS I've found are generally more expensive for components, except LCD displays where RS are about half the price.

I've used Digikey before, but not Rapid nor Cricklewood (yet).

**irving2008** · 10-08-2009

Originally Posted by tribbles

Farnell will charge the first time you use them, I think (that's what happened to a mate of mine [who asked me to order the bits for him instead, since I tend to chuck about £200 a month at them] and my brother).

Not as far as i am aware... just signed up, threw an order of about £30 at them, job done...

**HankMcSpank** · 10-08-2009

+1 to that.

I've only just started dealing with Farnell, as I'd always had in my mind that they were Draconian with their postal charges & minimum order requirements and made you jump through hoops as a private individual (they used to - & RS were worse from recollection!)

I'm actually pleasantly surprised at how they've changed (I guess it's 'adapt or die' in this new Global commercial market place we now live in) & I've put in some pitifully small orders with Farnell & never yet had a postage charge yet....normally get the stuff the next day too.

**tribbles** · 10-08-2009

Originally Posted by irving2008

Not as far as i am aware... just signed up, threw an order of about £30 at them, job done...

I think that's only if you don't order below £20 the first time.

Certainly they used to have an MOP of £20 (which meant I always over-ordered on items), but now they don't for me.