
KMC Controls
Revision J
Installing the controllers
KMC Tier 2 networks
16
Tier 2 wiring
You may connect up to 64 KMDigital controllers to the RS–485 connector. Use
approved shielded cable and the following principles when connecting a
controller to a Tier 2 (sub LAN) network:
◆
Use 18 gauge, twisted pair, shielded cable with capacitance of no more than
50 picofarads per foot for all network wiring. Belden cable model #82760
meets the cable requirements.
◆
Connect the
A
terminal in parallel with all other A or -A terminals.
◆
Connect the B terminal in parallel with all other B or +B terminals.
◆
Connect the shields of the cable together at each controller.
◆
Connect the shield to an earth ground at the other end.
◆
Use a KMD–5575 repeater if the cable length will exceed 4000 feet
(1220 meters). Use no more than seven repeaters per Tier 2 network.
◆
Place a KMD–5567 surge surpressor in the cable where it exits a building.
Tier 2 end of line termination switches
The controllers on the physical ends of the RS-485 wiring segment must have
end-of-line termination installed for proper network operation. Set the end-of-line
termination to
On
using the
EOL
switches. The KMD-5205 and KMD-5270
end-of-line termination is set with two switches located near the RS–485
connector. Termination in other KMC controllers may be set with moveable
jumpers or fixed resistors.
Illustration 2-1 Connecting controllers to a Tier 2 network
A
B
G
B
G
A
G
B
A
G
B
A
B
A
G
B
A
G
Earth ground
Ground shield in
one place only.