about the max LENGTH of SN65HVD12

Hello Nat

You are right in both cases and yes is a big difference. The first part that you talking about, is the stub length, in next figure you can see two examples about it.

The section where you see the formula is Bus termination and Stub length and in table 1 you can see different tr with different data rate and different stub length. On the other hand we have other section, Data Rate vs Bus length, and in this case is different connection (you don't use the same formula) you can see an example in next figure.

Also you need to be careful, because this connection depend of the data rate, in figure 7 on the same file you can see a graphic where you can see the response of the cable length vs data rate.

I hope this information can help you and please, let me know your comments.

Best Regards

Francisco

Hello Nat,

Also to clarify, max stub length is calculated from the minimum differential rise time not the maximum. So in this case the maximum stub length is 7.67ft, which is different than bus length as Francisco pointed out. The bus length can be much longer up to 4000ft but this is a trade off with data rate and the number of nodes in the network. 

Best Regards,

Casey