> > Now click on the little orange icon to re-enable the system, ENABLE goes > active and the AC Motor Power Relay switches ON. > > > > Interlocks prevent this while: > > 1. An ESTOP is still pressed > > 2. Spindle Motor Switch is in ON position, > > 3. Limit Switches are not in override if they were the cause of the > > ESTOP > in the first place and are still activated. > > > > The ENABLE from the PC goes through the BoB and out to the various > drives. This happens faster than the high voltage power supplies for the > drives. > > > > Is there a way to delay the ENABLE out? > > You put a delay block on ENABLE out enable flank? > > > Or will I be forced to build a circuit that makes sure the high voltages are > within range and use the output of that to gate the ENABLE? > > With a DC servo cutting gate driver voltage is not enough in case transistors > fail in opposite directions, guess it's not unlikely to happen if servo is > overloaded with a resulting over current in transistors. >
> > What's everyone else doing? > > For the emergency stop I would buy a real emergency button and connect so > that power is cut to make machine stop. Then pressed it should also be > sensed so that emergency stop in Linuxcnc is toggled. I would not trust > emergency button in Linuxcnc, the computer may stop responding for many > reasons. An extra switch maybe with personal padlock might also be good > then working with the machine, Injection mold machines at least sometimes > also have a mechanical lock. The ESTOP circuit is still set up the way it was in the original hardware. The NC ESTOP switch routes control to the AC contactor relay. There's a second NC contact that is sensed by the BoB and the system. The main contactor control circuit runs through a second NC ESTOP switch and also through a relay controlled by the BoB and therefore from the LinuxCNC Enable button. So either an operator generated ESTOP or a LinuxCNC generated ESTOP will open the circuit to the main AC contactor. As will a broken wire in that chain. > > Programming errors or other logical errors are common. Safety circuit should > be simple to check and understand though there might also be a cases there a > complex sequence which must work to keep alive is suitable, I would guess to > succesfully reading a bar code or QR code to keep alive could be made so that > likelyhood for an error in wrong direction is very low. > > Put a toggle signal in Linuxcnc, send it out on all motor driver outputs to a > transformer connected to a safety relay which is connected in series so that > power is cut if signal is not regularly toggled would probably add some safety > but in case encoder signal is lost a servo drive is likely to move to one of > the > end stops. > My softstart is controlled by a small 8 pin PIC. This s the same processor that also does the over voltage clamping and automatic fast drain of the power supply on loss of AC power. I can use that softstart signal to gate the enable to the STMBL drive. I'll do some more testing and post a drawing when I have a solution. John > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
