Have almost all my parts (pics), need servo advice

[kong]

My entire e-stop circuit is low voltage. I use a solid state relay to power the PSU, with the ground connected to the e-stop button. If you check Balsamans router thread, you will see his err/res manmager circuit. I have used this as the e-stop input to the computer, and have a 5v line which is switched on with the PSU that goes into this circuit as a "ghost" gecko drive if that makes sense. Again, the ground from that 5v PSU goes to the e-stop button, so when it is pressed, the PC knows it is in e-stop. Also, if any of the drives fault, the software knows about it. The third thing I have implemented is Mariss' idea of using a large resistor to "suck the PSU caps dry" which is levered across the PSU terminals in the event of an e-stop. If you look at the CAD_CAM_EDM_DRO boards file section, you will see it in there as "e-stop.pdf". Of course, I had to alter it a bit to use a low voltage system. This will aid in braking the motors quicker coz the cap isn't still supplying them with power. Hope it helps, but I think I'm rambling a bit! If you check that estop circuit, you will also see how the "latched relay" is used to turn on the power, but cuts out if the power is lost. This will prevent your motors coming back on when you release the e-stop button.

[Bloy2004]

I think I understand the use of limit switches through the software, but whats going to stop the motors if communication is lost and I'm not within reach of any mechanical cutoff. I'm sure that during an operation I might run to get a beer or something and if it(the malfunction) occurs during this time, well.....a metal machine can really tear things up.

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a guy without 20/20...or that trees and forest thing.
John

[Bloy2004]

Thanks Kong, I was typing my post while yours was being entered. this answers a lot of questions.

[kfong]

Breakout board sounds more expensive than it needs to be, is this optically isolated? Here's one for $5
http://www.embeddedtronics.com/breakout.html

Originally posted by ger21 I would think a good power supply is more like $150-$200. Breakout board = $125 Decent cables can be a lot more than nothing. That box on Jeff's site has a pretty nice case, more $$. Gerry