The Shop > CNC
DDCSV1.1 4 Axis controller
Joules:
nrml, all I did was use a continuity tester to determine which two pairs got connected when the button was pressed, the logic for the MPG ESTOP is short to ground for stop. I think you do have the option to change the logic to high, but you only need 2 wires to operate the stop.
For me an external ESTOP will also be fitted, this way the unit can still function if the pendant is removed, if the use logic high it won't allow the DDCSV to function without modifying the parameter when the pendant is removed.
John Stevenson:
That makes sense if all the logics are low. Any short and it stops.
awemawson:
Perhaps worth pointing out for future reference that conventionally an ESTOP chain is a closed loop running (potentially) through several devices / limits / sensors so that any device in the chain can interrupt continuity and drop out a safety relay or whatever.
So on a big mill for instance there might be a lubrication level sensor, door open sensor and an air pressure sensor all in series with the ESTOP button and the ESTOP safety relay coil.
This has the advantage that any broken wire or dislodged plug will trigger a stop, whereas if 'short to earth' is the operation, a broken wire or dislodged plug may not allow you to assert ESTOP
John Stevenson:
But is the E Stop circuit is fed a live and expects to see return to work any short or dislodged plug will put in in E Stop mode and it can't be reset until the fault is rectified.
Basically all switches need to be Normally Closed.
Some early machines and breakout boards for that matter had NO switches and only when closed and nothing happened did a fault become obvious.
Joules:
This is purely the Estop on the pendant. The controller Estop can be set up active high, +12v keeps things on so you can chain switches, as the pendant will be mostly out the way it won't be the stop of choice.
If you look at the bottom of the parameters screen, you see the Extended Buttons options. The Estop is set to active low (should have disabled it), as I don't have one so active high would disable the controller for now. Have just tested and confirmed that.
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