Devicenet Drop length/allowable current question

[Brent S in Cincinnati 0]

I have someone asking me about the drop length with respect to allowable current. It isn't an issue for the network I'm designing since it is all daisy chained on the trunk but I still need to answer the question. Page 1-16 in the Devicenet Media Planning manual has a chart of the allowable current for different drop lengths. Does anyone know why the current would depend on drop length? I understand why it matters for the trunk length with voltage drop on an 18 gauge conductor. I don't understand why a 6m drop would be limited to 0.75A or why the max for any drop is 3A. Thanks

[BobLfoot 302]

I could be wrong but DeviceNet has a nasty little hidden rule which says the highest voltage node and lowest voltage node cannot be more than 5 VDC apart. Current Draw on drops can cause this easily.