AXBB charge pump fault

[JAZZCNC]

1. Ideally I want any e-stop signal to be able to drop the contactor, even one from a pendant. That means the e-stop circuit has to monitor the reset status of UCCNC.

You can only incorporate the pendant in the E-stop circuit if it's a wired pendant, a wireless one is software-driven and will only put UCCNC into Reset mode and not do a hardware E-stop which is the correct way.
Also, the E-stop circuit doesn't and shouldn't be driven by software so you don't monitor UCCNC you inform it an E-stop occurred using inputs.

This also means I'm covered in two ways in light of an accident. First the AXBB-E will stop sending pulses, then power will be cut to the motor's PSU. The safety relay connected to the contactor achieves this - although I'm not clear why I need an extra relay in the system if I have a 24v coil on the contactor? Is it just a way of adding the switches in parallel instead of in series? I've seen circuits (such as https://youtu.be/6dKwOsrnkb4) that build a no volt release just using a contactor.

You don't actually need a safety relay and can indeed just use the contactor wired in a latching circuit, however, using a separate Relay gives more control. It doesn't need to be a safety relay either just an ordinary ICECUBE type relay works just fine.

This relay is known as the MASTER relay in the circuit because it controls all the safety and won't be allowed to energize unless all the safety on your machine is correct.
Only when all is correct on the machine will the MASTER relay be allowed to latch, When it does it will do several things.!
#1 sends a signal to UCCNC saying it's ok to allow a Reset.
#2 power the contactor for the drives.
#3 power any other contractors in your system or allow voltage to reach contractors or relays ie: For dust extraction
#4 Turn on any LED's ie: light tower etc

2. I also want any e-stop to put UCCNC into reset mode which means the AXBB-E needs to monitor the status of the e-stop circuit.

3. The contactor should stay off following power outage and require a manual button press to re-energize the coil.

#2 As mentioned above, you inform the AXBB-E using inputs rather than it doing the monitoring. If it sees the input HIGH or LOW depending on how you configure the input then it won't allow the software to RESET.

#3 This is known as a latching Circuit and is easily done using a relay.

My conclusion was the only way to accomplish this without getting stuck in a feedback loop between 1 and 2 was to connect all e-stops to the AXBB-E then have it control a relay with the charge pump output pin as shown in the example circuit at the end of the manual. Does that seem like the right approach to you all? I really appreciate your help!

The Charge pump Output is not designed for this purpose, it's designed to monitor the connection between PC and controller so if the software crashes or PC dies the AXBB-E sees this and disables the Output. This, in turn, would drop the relay which should be incorporated into the E-stop circuit and before the MASTER relay.