Ready Steady Eddy

[EddyCurrent]

Dean, you are correct in that every situation has to be risk assessed on it's own.
I also think the braking resistor is not required because of the fairly low inertia of the load.
I agree that for DIY either strategy is fine but maybe not everyone reading this is in a DIY situation, in which case they should be referring to the relevant regulations.
The main aim of this is to get a good emergency stop system using the gear we've got.

It would be useful if we could define some scenarios and strategies for stopping a cnc machine, your input is valuable here.

I've listed some ways to stop the machine and the strategy to adopt, I'm not saying it's comprehensive so please add or amend as you think.

*emergency stop button pressed - strategy 1 or 2
*limit switch activated (not home limits) - strategy 2
*spindle over temperature switch activated - strategy 3
*Stepper driver alarm relay activated (e.g. AM882) - strategy 3
*'Stop' button pressed - strategy 4
*Charge Pump error - strategy 1 or 2

Strategy 1
----------
* remove power to all devices immediately

Strategy 2
----------
* remove power to stepper drives immediately
* remove power to ancillary devices immediately e.g. air, water, dust extraction
* issue stop command to VFD then after delay remove power to VFD

Strategy 3
----------
* issue audio visual alarm before taking action (with time delay)
* controlled stopping of all machine actuators and ancillary devices
* leave power supply on to VFD

Strategy 4
----------
* controlled stopping of all machine actuators and ancillary devices
* leave power supply on to VFD