The system is a 4600 IRC5 and randomly throws this fault up a couple of times per week. I have replaced the safety board and power supplies within the controller. Control voltage monitored consistently at 24.75v. Is there perhaps a way to turn the voltage test off?
This is probably where the error is coming from, you should save a diagnostic file immediately after you get the error (before doing anything else) and send it to your local ABB robotics team. From this file the factory support team can tell if it is the error is coming from the SafeMove 2 board.