KMD-5575
7
Installation and Operation Guide
EIA-485 terminals are used for connections to a network of controllers. Refer to
this checklist of best practices:
◆
Connect the shields of the cable together at each device. Do not connect the
cable shield to the circuit GND terminal on the KMD-5575.
◆
Connect the shields to a good earth ground at only one end of the segment
;
tape back the shield ground at the other end.
◆
Use a KMC KMD-5575 repeater after every 31 controllers or if the cable length
exceeds 4,000 feet (1,220 meters). Generally, use no more than
four
repeaters per
EIA-485 (KMDigital or BACnet) network. (For smoke control applications, the
maximum total length of the EIA-485 network cable, including all repeaters, is
4,000 feet.)
◆
If the repeater is at an end-of-line position, refer to Illustration 3 and the “Con
-
figuration/EOL” section. The end-of-line connection will have only one wire
attached to the A and B terminals.
◆
For reliable operation, use Belden cable model #82760 or equivalent (18-gauge,
twisted, shielded, 50 picofarads or less) for all network terminal block
connections.
◆
Connect the nodes of the network in a daisy-chain arrangement:
Connect the
•
A
terminal in parallel with all other
A
terminals.
Connect the
•
B
terminal in parallel with all other
B
terminals.
◆
“Star” networks (three or more conductors under the
A
and
B
terminals) are
not
recommended. “T” networks can accomplish the same goal.
◆
Place a KMC KMD-5567 surge suppressor in the cable run where it exits a build
-
ing.
For smoke control applications, the maximum total length of the MS/TP network
cable, including all repeaters, is 4,000 feet. The MS/TP communications network is
supervised in smoke control applications, and the ground fault impedance value
for the circuit is 0 ohms. For specific information on smoke control systems, see
Smoke Control Manuals 000-035-08 (BACnet) and/or 000-035-09 (KMDigital).
Configuration/EOL
Prior to operating the KMC KMD-5575 Network Repeater-Isolator Module, you
may need to configure the module for an End-of-Line (EOL) termination. See Il
-
lustrations 3 through 5.
If the module is connected to the network segment in an end-of-line position (only
one set of wires connected to the terminal—refer to “Network Connections” sec
-
tion), place the EOL jumper in the “On” (shorted) position. If the module is not
connected in an end-of-line position (two sets of wires connected to the terminal),
then leave the jumper in the default “Off” position.
Power Connection
Before connecting power, make certain all connections and EOL jumper positions
are complete and correct. Connect a KMC Controls 24 VAC Class-2 (power limit
-
ed) transformer of the appropriate size to the two power connections on the lower
terminal strip. Connect the ground side of the transformer to the
–
terminal and
the AC phase to the
~
(phase) terminal. See Illustration 3.
For smoke control applications, the KMC XEE-6112-100 transformer is required.
See Smoke Control Manuals 000-035-08 (BACnet) and/or 000-035-09 (KMDigital)
for smoke control application information.
