Ready Steady Eddy

[cncJim]

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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.
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This is a great idea Eddy, great for noobs like me. Might be nice to add example circuits for each strategy (might be getting carried away now...)?
I have made some changes based on some of the feedback and tried to make clear which things should be done in hardware and software, hope that's ok. Maybe it could make a good sticky?

List of scenarios and possible strategies for dealing with them.

Scenarios

• Emergency stop button pressed - Strategy 1, 2 or 2.5
• Limit switch activated (not home limits) - Strategy 2 or 2.5
• Spindle over temperature switch activated - Strategy 3 or 3.5
• Stepper driver alarm relay activated (e.g. AM882) - Strategy 3 or 3.5
• 'Stop' button pressed - Strategy 4
• Charge Pump error - Strategy 1, 2 or 2.5

Strategy 1

• remove power to all devices immediately (Hardware)
• Inform control software of Estop condition (Software)

Strategy 2

• remove power to stepper drives immediately (Hardware)
• remove power to ancillary devices immediately e.g. air, water, dust extraction (Hardware)
• issue stop command to VFD then after delay remove power to VFD (Hardware)
• Inform control software of Estop condition (Software)

Strategy 2.5

• Issue stop to stepper drives then after delay remove power to stepper drives (Hardware)
• issue stop command to VFD then after delay remove power to VFD (Hardware)
• remove power to ancillary devices immediately e.g. air, water, dust extraction (Hardware)
• Inform control software of Estop condition (Software)

Strategy 3

• issue audio visual alarm before taking action (with time delay) (Hardware/Software)
  After delay:-
• Stopping of all machine actuators and ancillary devices (Software - "Stop" Command)
• leave power supply on to VFD

Strategy 3.5

• issue audio visual alarm before taking action (with time delay) (Hardware/Software)
  After delay:-
• inform control software to activate Feedhold (Software)
• Move to safe Z (Software)
• Issue stop command to spindle (Software)
• leave power supply on to everything

Strategy 4

• Stopping of all machine actuators and ancillary devices (Software - "Stop" Command)
• leave power supply on to VFD