Hello everyone, I am sure these questions are asked all the time but I have found nothing that really covers what I am looking for. (But maybe I am not too good with the search.)
I have built a CNC Gantry router based on the KRMx01 design from Kronos Robotics. But instead of using the electronics and Mach3 he suggested, I am using electronics, motors and Linux CNC. The basic machine is up and running and I am using it to cut more parts for the machine. I am to the point now that I need to think E-stop, limit and home switches, vacuum control (dust collection) and router PID. My setup is a C10 (cnc4pc) BOB, (4) CW230 stepper drivers, (2) 36vdc power supplies (each feeding 2, CW230 drivers) and (1) 5vdc supply enabling the BOB. The CW230 drivers do not have a charge pump or anything like that, though they do have a pin called REST that according to the sparse documentation says will allow the motor to free spin. (I guess it may be considered an enable) Because I have a couple of teenage boys and a wife who have expressed an interest in using the machine, I need to make sure it can be stopped in the event something unplanned happened. Here is my thought and also where I need some guidance on best practice or acceptable practice. 1) Connect external E-Stop to input pin on controller 2) Use HAL to logic glue the AXIS GUI estop and AXIS GUI Power button together so that IF both E-Stops are on the closed position AND the power is on in AXIS GUI THEN allow charge pump signal on output pin of BOB 3) Connect cnc4pc part C4 (charge pump) inputs to charge pump signal on the corresponding output pin on the BOB. The output of the charge pump is a relay with the choice of NO or NC contacts. If the charge pump frequency falls above or below the operating threshhold, then use this output as a trigger. 4) Connect the output to (2) C8 (cnc4pc part number) AC relays with 5 volt input to connect / disconnect the AC side of the (2) 36vdc power supplies that power the CW230 stepper drivers. In my simple mind, this should provide the following safety feature. A) The machine will only run if both E-Stops (external E-Stop and AXIS GUI E-stop) are in the closed positions AND the power button (AXIS GUI) is on. Allowing the Charge pump signal to be generated on the output pin of the BOB enabling the power to the motors through the Charge Pump and AC Relays. B) If either Estop is opened, then the Charge pump signal will be stopped causing the power to the supplies to be cut by the AC Relays from the Charge Pump. C) If the computer crashes and the LPT port is left in an unknown state, the charge pump signal should be gone causing the power to the motors to be cut. D) Avoid any start up random signals to the LPT port being sent to the motors because the drivers will not be powered up. Kind of long, but am I on the right track here. Just want to have a margin of safety if my boys or wife is trying to use the machine. If you are interested, I have a detailed build of this machine, including screen casts of LinuxCNC hybrid install, configuration to this point, etc on my website which you can see by going to http://myheap.com/krmx01-cnc-router/krmx01-build-log.html I will be adding this (E-Stop, charge pump, AC relays) to the pages too including how to configure and the logic behind the solution. I am hoping it to be a resource to others like me who are only in it on the hobby level and still have the HUGE learning curves to make it over. Many thanks, Joe ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
