Emergency Stop (custom machine)

  • Hi all,

    We've set up a Duet controller to run a home built plasma cutter and want to add an emergency stop button to it. I've read https://duet3d.com/wiki/Connecting_an_Emergency_Stop_button about 100 times and tried multiple configurations of the M581 code, but can't seem to get it working properly.

    Here's what I have so far:
    E-Stop button is wired to the two outside pins on the E0 endstop.
    If I press the E-Stop button, the LED on the Duet board will light up. I also will see a "halted" message on the web page.
    My code is:
    M581 E0:1 S0 T0

    If I move the cutting head out into the middle of the table and home it then press the E-Stop button, nothing happens,



  • It might depend on how you have wired the estop - so have you tried S1 instead of S0 (that's how mine are configured). Also, if it's only wired to E0, then you don't need "E0:1" just E0 will work (but having E1 as well shouldn't matter). Finally, you might want to add C0 to the M581 so that it triggers at any time. Otherwise, if the machine is running a macro such as homing, then it'll wait for that macro to complete before the trigger gets acted upon.

  • I'm adding e-stop like features for the printer at work. I would personally avoid a software controlled e-stop unless it was on a dedicated safety controller. These tend to be not cheap and often come with there own perculiar programming methods.

    I've chosen to split my power supply 3 ways. 5V psu for duet. 24v psu for fans (think fan stopping on a hot hot end) and 24v for the steppers and hot bits. I've a relay (actually a pair of force guided relays, but thats probably overkill for your intention) whose coil is grounded by the duet PSU on pin and fed by a non-latching push button initialy and then by spare poles on the relay once the relay is energised. The relay cuts the mains to the stepper/hot bits psu. All contacts are protected by fuses to minimise the chance of contact welding. In use the duet needs to be on and M80 command sent then the reset button will arm the more dangerous parts of the system. I hope to setup the duet to drop the PSU on signal on heater fault. The user would need to visit the macjine to restart. That is intentional as an e-stop implies something went badly wrong and things should be checked over.

    If you are however just want a convenient stop process button, rather than an emergency stop then my ramblings are irrelevant!

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