On 9/27/2013 7:38 AM, Marius Liebenberg wrote: > Cheap yes until you loose a limb. There is no cost to high when it come > to safety guy. > > What happens if you are busy with a cleaning or changing a tool and the > pc falls over turning the spindle on. I have seen it happen.
Won't be falling over because it's going to be mounted to the inside of the door on the huge NEMA cabinet where the original Anilam computer was. The PC, the power supplies, the BOB, the drives, all the bits and pieces of the control system will be in that cabinet. I'll be re-using the original rotary switch for the 115V system power and the original reset button on the box (which for some reason was never labeled) will be wired to the PC in place of its power button. I'm also planning on using the original spindle control relay setup, with the addition of a manual off switch so when it's time to do a tool change the spindle will be completely cut off from power. Something Anilam did a lot of was using cables with many unused wires in them. The cable going to the spindle control box look to have about 20 wires but there doesn't look to be that many traces leading away from the connector. For the limit switches on the Z axis there's a 4 wire cable but only two wires are used. It duplicates the effect of a single center switch (like it has on X and y) with two end stops. I can use those two spare wires with a switch to control a spindle power cutoff relay. When it comes to mixing computers and machines capable of doing damage I always think of the Therac 25 and how its reliance on software control of everything led to people dying in rather gruesome ways. Since the ATX standard introduced the 'soft power' system to the PC, I've never been a fan of that. I've always preferred switches where OFF is OFF and nothing but direct human action can move that switch. ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
