@learningautomation: Back at this project to remove some bugs that have shown up. You never get it right first time. This one was a blocked waste conveyor issue locking itself into an error. Waste clamp to hid wood whilst it cuts would, under just the right conditions, clamp as a fault triggered, stay clamped and then trigger the same fault as the sensor was blocked. Needed to unclamping error to release itself if this condition (bad timing!) happened.