We are working on a cell with two UR10/CB3 robots and a CompactLogix PLC coordinating their motion with the line and other hardware.
Our PLC programmer was reviewing the EtherNet/IP structure, and noticed that there is a bitfield for robot safety status
safety_status_bits, which appears to be exported over other data interfaces as well. However, when he implemented logic based on the useful-looking signals, the cell is experiencing many faults apparently without cause. It was determined that the ST bit, which means “Is stopped due to safety”, is the culprit. As far as the cell surveillance cameras show, the safety scanners are not being violated, and the PLC registers no other events in its safety routines.
Where can I find a guide on specifically what each of the 11 bits in this structure mean, beyond the terse descriptions given in eip-iomessage.pdf and elsewhere? A transition diagram would be eminently helpful.
Welcome to the forum! The bits are listed in our RTDE guide, snipped below:
If the system is stopped due to safety, one of the other bits (protective stop, safeguard stop, etc.) should also be high.