imho that is just chasing your own tail - trying to get DeviceNet working before you got robot to boot up without error messages.
But if you insist here you go:
what is the total length of all devicenet cables in a network, and if you are using drops what is the cumulative length of all drops? what is the baud rate?
there are limits:
125kbps: total bus length max 500m, total drop length max 125m
250kbps: total bus length max 200m, total drop length max 78m
500kbps: total bus length max 100m, total drop length max 38m
max drop length is only 6m, and this is IF you are using proper thick DeviceNet cable for a trunk (drop may be thin DeviceNet cable).