Years ago. DevicNet Guru (Ken Roach) helped me out on a job and told me to get troubleshooting tools. So I carry a Devicnet Detective, a netmeter, and every different devicnet connector you can think of. I charge a premium to get these tools out of the service van. They are always in there.
Long back story I will try to make short. As I remember the events its need more the a few years ago. I did a system PLC, 2 ABB robots and a conveyor on DNet. It was running for years. I got called that the robots where faulting. Both ABB where reporting that they could only be in controlled by 1 master. The conveyor had a photoeye on it that was powered off the DNet bus. The sensor cable was worn thru by the conveyor belt lacing. When the metal lacing shorted out the DC bus the conveyor I/O module 100-DNY would take the network down. The ABB robots tried to reboot the slave units and saw that they where already part of a scsnlist and faulted out on a multiple master fault.
I used both the Detective and Netmeter to see the DC bus go low and high. I don't carry a scope with me.
Ken Roach feel free to correct my diagnosis or terminology where I screwed it up. It was been. Many years since back then.
I get called out about once or twice a year on DeviceNet issues. About every 3 yo 5 years yo start up a new MCC with DeviceNet.
Long back story I will try to make short. As I remember the events its need more the a few years ago. I did a system PLC, 2 ABB robots and a conveyor on DNet. It was running for years. I got called that the robots where faulting. Both ABB where reporting that they could only be in controlled by 1 master. The conveyor had a photoeye on it that was powered off the DNet bus. The sensor cable was worn thru by the conveyor belt lacing. When the metal lacing shorted out the DC bus the conveyor I/O module 100-DNY would take the network down. The ABB robots tried to reboot the slave units and saw that they where already part of a scsnlist and faulted out on a multiple master fault.
I used both the Detective and Netmeter to see the DC bus go low and high. I don't carry a scope with me.
Ken Roach feel free to correct my diagnosis or terminology where I screwed it up. It was been. Many years since back then.
I get called out about once or twice a year on DeviceNet issues. About every 3 yo 5 years yo start up a new MCC with DeviceNet.
on the 7 position. I was expecting to see 0 volts...