Kill that Puppy,

[CharlieM]

Now that I have learned that disconnecting a stepper motor while under power burns up the driver chip, could I just put a on/off switch in series with the power supply and the driver board?

[ger21]

You should have an E-stop button that kills power to the drive, as well as kill power to the spindle motor. If you turn off the drive while cutting, and the spindle motor is still cutting, it can take off in any direction do a lot of damage to both the part and the machine, possibly.

[mredican]

Forgive my ignorance... what is an "E-stop button"? Can you also just connect a single switch to all three limit switches?

Matt

[CharlieM]

That was a good alert Gerry, what I was thinking would only work if I was drilling, if I was milling then the mill cutter could drag the part into itself and do serious damage.

So, I will need to kill power to the stepper motors and the spindle at the same time.

[ger21]

Originally Posted by mredican Forgive my ignorance... what is an "E-stop button"? Can you also just connect a single switch to all three limit switches? Matt

Emergency Stop - Big Red Button

[JavaDog]

If you aren't using a relay board for your spindle, how do you set it up so you can kill the spindle power? Or do you have to use a relay board?

[ger21]

You can get E-stops that will switch more than 1 circuit. But I just looked at the ones McMaster-Carr sells, and they were all rated at only 6a, so I guess you'd have to use a relay.

[JavaDog]

Originally Posted by ger21 You can get E-stops that will switch more than 1 circuit. But I just looked at the ones McMaster-Carr sells, and they were all rated at only 6a, so I guess you'd have to use a relay.

Hmm...maybe I should have spent the $46 and ordered the relay board too when I got the rest of my CNC4PC boards (which are very nice, btw).

[Bloy2004]

Javadog,
out of curiosity....What boards did you receive from CNC4PC? I got one "breakout" board for one parallel port but may get another for a second PCI Parallel port card..to expand input/output options. Have only looked and contemplated about their other "addons".
I picked up a Bob campbell's relay board on ebay for $25 unused.

[JavaDog]

Originally Posted by Bloy2004 Javadog, out of curiosity....What boards did you receive from CNC4PC? I got one "breakout" board for one parallel port but may get another for a second PCI Parallel port card..to expand input/output options. Have only looked and contemplated about their other "addons". I picked up a Bob campbell's relay board on ebay for $25 unused.

I bought the Breakout board, Charge pump, and Mini PSU.

[bkukowski]

just slap some isolated high current relays on your proto board and use a resistor or reg to power them. You would probably want switched current going through the wires on the normally open relay circuit, then have a normally closed "e-stop" switch that cuts power to the relays when it is pressed. Make sure the switch stays open and it is not a momentary switch. Please let me know if this is right or if you understand what I am talking about. All in all it should be $20-$30. I remember seeing e-stop buttons in my mouser catalog (www.mouser.com)