Issue
Wants to know the correct termination specification for each different I/O modules and different IOU networks.
Environment
- NC1 - CX9900, CX9940
- NC2 - CX9680
- IOU modules
Cause
Different type of terminations are required for different type of I/O modules (ACC-LON and FTT-10A) and different topologies (Bus topology, Free topology and Doubly terminated Bus topology).
Resolution
- ACC-LON requires two 120 ohm resistors at both ends of the bus. One between pin 1&2 of the I/O module on the NetController side and the other one between pin 1&2 of the I/O module at the last node of the bus.
- FTT-10A Free topology requires one 52.3 ohm resistor between pin 1&2 at any place on the bus.
- FTT-10A Doubly terminated bus topology requires two 105 ohm resistors. One between pin 1&2 of the I/O module on the NetController side and the other one between pin 1&2 of the I/O module at the last node of the bus.