Denford Software & Machines

Hi,

I previously managed to control the stepper motors in my Denford Micromill 2001 (2001 model) by wiring directly between the parallel port to the 96 way pin connector.

I accidentally earthed the Sprint spindle speed control and had to replace it (oops!).

The newly replaced spindle control board works fine, but I cannot control the steppers any more (Mach 3). There are few things quite as depressing as getting the steppers to respond, then returning to square 1! I was so close

I have exactly 30V across terminals 1 & 2 and 4 & 5 of the 28V AC input connector (TB11); hmmm.

This post seems to suggest that this voltage is too high and will cause the card to shut down:

viewtopic.php?f=41&t=3092&hilit=denstep

By this logic, it would seem I need to replace the power supply? Could it be that this has been damaged following my aforementioned mistake earthing the spindle control board?

Many thanks!

you may have damaged the parallel port or breakout board, do you have another to try.

I tried another computer, but no luck.

The parallel port is wired directly to the 96 way connector on the Denstep card (no breakout board). All connections appear good.

good news.

The connections between the computer and the Denstep card, I mean. Still no life out of the steppers

are the steppers locking

I'm sorry, I'm a bit unsure of what you mean by locking? There is currently no response from the stepper motors at all when I try to jog the axes in Mach 3. Not even a noise.

Interestingly, if I remove all my connections on the 96 way connector and replace the top card, it seems to power up ok as the red segment display displays an 'L'. I'm hoping this is a sign that I can't have done that much damage?!

When the machine powers up the steppers will lock in position when they get power, before that they can be turned by hand.

Oh, I see

They can still be turned by hand when everything is energised, which I guess points to a problem with the card?

is the esr (emergency stop relay) energised. This turns on when you power up the machine and without it on the stepper drivers will be off.

When I turn the main power key, I have 29.5V across the ESR terminals at the Denstep card (wires 13 & 14, terminals 1 & 2 in the TB11, 28V AC input section).

Prior to turning the main power key, there is 0V across the same terminals.

So, as far as I can tell, the ESR appears to be doing it's job?

can you see the emergency stop relay turn on.

I can;the switch moves from '0' to '1' as it turns on

When you replaced the Baldor top card did the steppers energise(lock) then?
I'm not sure exactly how the stepper stage gets enabled on the bottom board, but I'm guessing it needs the STOP input and maybe an enable signal on the 96 way ?

they will normally enable with the top card removed, and all you need is pulse and direction signals.

Aharman, where are you based?

You have said you have 30V on the input to the control card. As the display is lit there is no problem with the PSU. If that was too high the regulators shutdown loosing the logic that controls the processors and the 7 Seg display.

You also say you can turn the steppers when the motor supply is on the control card.

Have you checked the fuse on the bottom card as this supplies the motors?

Have you looked closely at the driver chips on the board, If they are blown you can generally see the damage to the units.

Angel-tech: I am based in Bournemouth, UK.

Steve: Thanks for your reply. I've checked the fuse and it's fine. Therevdoesn't appear to be any damage to the chips.

that's a shame, i'm off up to Manchester tomorrow and thought if i was passing you i could have called in and had a look at it.

Wow, there'd be no need to go to that much trouble, but that's very kind of you to consider doing that; thank you!