Thanks! The e-stop design has given me quite a headache. My main design goals are:

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. 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.

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.

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!