Thank you for your input. I think I am misunderstanding more than I thought.
I had looked at that document as part of my planning, and currently have the MX4660 Estop+/- pins 'shorted' as they describe when not using an Estop. When shown with an Estop button the document has it connected NC, which from my reading seemed to be recommended for safety circuits/sensors for the reasons you mention - in case PSU power is lost or a cable is cut you would know because everything should stop and show faults.
This is why I thought it should be normally closed in the relay.
In the forums I read that for this type of relay I needed to make sure it was set to 'high', so that it reads 0V across the IN1 and com - I did this.
I believe I am unclear on what happens in a non-fault situation.
On power up, what does the 12V to the D+/D- of the relay do? Is the coil energized at that point? Are the NC and NO outputs now held in that state - i.e., the NC is actually providing a closed circuit? That is what I thought.
When Masso's ES output is triggered, does it send a 5V TTL signal to the relay IN1? What does this signal do? Does it (through the optocoupler) cause the coil to de-energize and therefore change the state of the NC and NO switches - i.e., so now the NC is an open circuit, and therefore the MX4660 sees that as a fault? That is what I thought.
Please know that I am not at all questioning your information. Rather I wanted to share my thinking, and if you are willing, I would really appreciate it if you could help me understand what part of my thinking if any is correct, and what is not.
Also, as an aside, while I was waiting for support I tried to trigger the IN1 relay from the POS+ of my small 5V PSU. A red LED flashed and then no longer comes on. Did I ruin that part of the relay by doing this?
I am moving into the part of my controller build now where I am connecting inputs and outputs on my Masso and MX4660, and I am really trying to be careful so as not to damage any of my valuable components.
Tom
