Colin MacKenzie wrote: > EMC2 has 3 outputs for spindle control (that I see) PWM Output, CW and > CCW on the Parallel port.
EMC can be configured (using HAL) for many different spindle control arrangements. If you have PWM, CW, and CCW on your parport, it is because you (intentionally or not) configured it that way. > I have a simple relay board I made using > grayhill solid state relays. These relays are opto-isolated. Because my > relays are 3A 140v rated and my rotozip is 5am motor, I used 3 of them > in parallel to comfortably run the rotozip with lots of amp headroom. Not sure solid state relays can be paralleled or not. I bet if you measured the current through each one you'd find it is NOT evenly distributed. Might even be flowing through only one of them. A 3A relay will handle "5A" at least for a while, and under light load the rotozip probably draws less - maybe even less than 3A. So you might be running on one relay right not and not know it. > I don’t know what the effect of connecting my SS relay board to the PWM > output would do. Since my relay board is SS its not like I have > armatures that will arc and sieze or something due to PWM switching. Solid state relays typically can only switch on and off twice per line cycle - they use triacs or SCRs that turn off when the current goes through zero. PWM is usually much faster than that, in the kilohertz range. Your relays will NOT work properly with a PWM input. > But > I don’t know how the rotozip would take to quickly switching power on > and off in a PWM situation. Anyone here attempted this sort of thing? Is > the PWM output always duty cycled? Yes - that is the definition of PWM - Pulse Width Modulation. > Or is there some setup to make it > always on or off. Yea, don't use PWM. I suspect that the CW and CCW inputs would work just fine. When the spindle is off, they should both be off. When the spindle is going one way or the other, one of the two should be on. > I was only intending on manual speed control until I > find a good deal on a real spindle and controller. Should I just connect > it to the CW output and use that to switch spindle on/off? Yep. > Also: If anyone has information on a decent spindle for a good price > please let me know. (maybe direct email.) I will cut a lot of soft > aluminum, plastics and some wood. I have a moving table design with > solid parts, linear bearings and ball screws. > > Btw: the relay board was cut and drilled using emc2 and it worked well. > > Thanks, > Colin I think some folks use routers - Porter-Cable, etc. Only good for light cuts in aluminum though, and you have to keep conductive chips out of the vents. Real metalworking spindles are a complex (and expensive) world. Regards, John Kasunich ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
