Ready Steady Eddy

[EddyCurrent]

That's interesting. I was thinking about this and is it a good idea to have the spindle over temperature hooked into the estop circuit? My thinking being that if the spindle starts to over heat, I would for sure like to be made aware of it but I wouldn't the whole machine to emergency stop and risk damage (would anything potentially be damaged as a result of an estop or have I got the wrong end of the stick? I have read different things/advice so far. Obviously if it was a real emergency then damage to the equipment is the last thing to worry about). Maybe a two stage system with a warning buzzer/light when the temp hits the first level and then estop if it rises to the next level? Sorry just thinking out loud!

Yes this crossed my mind, I may change this strategy at some point. To be honest I just included that option at the last minute without much thought. Just a quick thought, maybe if it was an input to the breakout board it could tell Mach3 to close down in an orderly fashion home itself then stop the machine.

Following Dean's reply and also my tests in another thread I have updated 2 of the drawings so that the X,Y,Z home limits are in series but the A home limit needs to be separate because it's slaved off X as I'm using 2 individual motors driving two ball screws. I'll still bring 2 core cables back from each switch to the machine mounted terminal box but I'll series them up at the terminal rail. (leaves option for later if need be)



With regard to safety, final, ultimate limits (whatever you want to call them) then it is not a good idea to involve software which is why I have them in the hardware E/stop circuit.

[cncJim]

Yes this crossed my mind, I may change this strategy at some point. To be honest I just included that option at the last minute without much thought. Just a quick thought, maybe if it was an input to the breakout board it could tell Mach3 to close down in an orderly fashion home itself then stop the machine.

Nice thought! As a result of the input would it be possible instruct Mach to issue a Feedhold, raise to safe z and shutdown the spindle? Would be nice to be able to continue the job after checking things out?

Following Dean's reply and also my tests in another thread I have updated 2 of the drawings so that the X,Y,Z home limits are in series but the A home limit needs to be separate because it's slaved off X as I'm using 2 individual motors driving two ball screws. I'll still bring 2 core cables back from each switch to the machine mounted terminal box but I'll series them up at the terminal rail. (leaves option for later if need be)

My machine also uses two motors driving x - interesting to see how this should be wired.

I'll still bring 2 core cables back from each switch to the machine mounted terminal box but I'll series them up at the terminal rail. (leaves option for later if need be)

That's a good idea. I have quite a bit of Cat5 cable and I was thinking of using this. Figured the twisted pairs would be good for noise rejection. Second thought, the Cat5 is also shielded but I am thinking the cable may be too bulky/stiff...

With regard to safety, final, ultimate limits (whatever you want to call them) then it is not a good idea to involve software which is why I have them in the hardware E/stop circuit.

Agreed - I haven't designed my safety circuit yet but was planning on basing it on the example circuit in the Mach 3 manual.