Johnson Controls NIE39 Installation Instructions Manual page 11

Table 1: MS/TP Bus Rules
Category
2
Cable Type
Terminations
1 If the TEC Thermostat Controllers or third-party MS/TP devices are connected to the FC Bus, the maximum total number of
MS/TP controllers on an FC Bus is 64 for NIE45 models and 32 for the NIE35 models. The maximum cable length per bus
segment is 1,219 m (4,000 ft) and the maximum total FC Bus length is 3,658 m (12,000 ft).
2 Refer to the MS/TP Communications Bus Technical Bulletin (LIT-12011034) for more information on alternative cable types
and lengths.
Table 2: N2 Bus Rules
Category
General
Number of N2 Devices
Supported
Line Length and Type
Cable
Terminations
Table 3: Modbus RTU (RS-485) Bus Rules
Category
General
Number of FC Devices
Supported
Bus Length
NIE39/NIE49 Installation Instructions
Rules and Maximums Allowed
Stranded 0.6 mm (22 AWG) 3-wire twisted, shielded cable is recommended. Stranded 0.6 mm (22
AWG) 4-wire (two twisted-pairs) shielded cable is acceptable.
Note: The + and - bus leads should be a twisted pair. On FC Bus applications using 4-wire (two
twisted-pairs) cable, isolate and insulate unused conductor. Refer to the MS/TP Communications
Bus Technical Bulletin (LIT-12011034) for more information.
Two FC Bus devices with EOL switches in the ON position, one at each end of each FC Bus segment
Rules and Maximums Allowed
MS-NIE391x-x and MS-NIE491x-x models (only) support one N2 Bus trunk.
Only daisy-chained N2 devices (with maximum stub length of 3 m [10 ft] to any device)
MS-NIE491x-x models support up to 100 N2 devices (maximum) on the N2 trunk with no more than
two repeaters between an NIE49 and any device and a maximum of 50 devices between repeaters.
MS-NIE391x-x models support up to 50 N2 devices (maximum) on the N2 trunk with no more than
two repeaters between an NIE39 and any device and a maximum of 50 devices between repeaters.
1,500 m (5,000 ft) twisted pair cable without a repeater
4,500 m (15,000 ft) twisted pair cable from NIE and the farthest N2 device (three segments of 1,500
m [5,000 ft] each, separated by repeaters)
2,000 m (6,600 ft) between two fiber modems
Solid or stranded 1.0 mm (18 AWG) 3-wire is recommended. Solid or stranded 0.6 mm (24 AWG) or
larger 3-wire or 4-wire (two twisted-pairs) is acceptable.
Note: The + and - bus leads should be a twisted pair. On applications using 4-wire (two twisted-pairs)
cable, isolate and insulate unused conductor.
Preferred Termination Configuration: Two N2 devices with EOL switches in the ON position, one
at each end of each N2 Bus segment
Minimally Required Termination Configuration: At least one N2 device with an EOL switch in the
ON position somewhere on each N2 Bus segment
Rules and Maximums Allowed
Two Modbus integrations supported per NIEx9. See
For Modbus RTU integration, only daisy-chained devices are supported
MS-NIE491x-x models support up to 100
than two repeaters between an NIE49 and any device and a maximum of 50 devices between repeaters.
MS-NIE391x-x models support up to 50
than two repeaters between an NIE39 and any device and a maximum of 50 devices between repeaters.
1,500 m (5,000 ft) cable per bus segment without a repeater
4,500 m (15,000 ft) cable from NIE to the farthest FC Bus device (three bus segments of 1,500 m
[5,000 ft] each, separated by repeaters)
2,000 m (6,600 ft) between two fiber modems
Table 10.
1
Modbus RTU devices total on the FC Bus with no more
1
Modbus RTU devices total on the FC Bus with no more
11