CAN BUS Device Net troubleshoot

Got a complicated problem with one of our machines using DeviceNet. Im kinda new to this but what happens is that we have several nodes in the machine including a staübli 6axis robot. For some reason when the (deadman's switch) or servo motors recieve power it knocks all of the nodes off like they are loosing connection. If we exclude the robot in the equation the nodes doesnt fault. Even with an external power supply to the robots modules this happens. Does anyone have any idea what to look for here? Have tested all the other nodes as well but works aslong as the robot doesnt recieve power.
It sounds like this could be a grounding issue or a shielding issue (due to EMI generated by the robot).

According to the DeviceNet spec (The CIP Networks Library Volume 3, Chapter 8), the V- signal is used as the 0V reference for the CAN_H and CAN_L signals (technically the 0V logic ground connection to V- is through a Schottky diode, so the 0V logic ground may be a maximum of 0.6V higher than V-). Therefore, all devices must have a common V- connection. If all devices are not properly connected to the same V- reference and if the robot is injecting noise, AC power fluctuations, etc. onto the V- signal, this can cause communication issues.

The cable shielding (assuming the cabling is shielded, and if not, it should be) should be grounded at one location only. The spec recommends that single location be the power tap and that grounding near the physical center of the network is desired. The trunk drain/shield should be attached to the power supply ground or V-. This should then be attached to a good earth or building ground.

Also make sure that the bus is properly terminated. DeviceNet requires a termination resistor to be installed at each end of the trunk (121 ohm, 1% Metal Film, 1/4 Watt).
Did you get a fault code in the scanner display?
Per your description the line is not working, what happen if disconnect all the nodes, and connect only the robot to the scanner?