Honeywell 7800 Series Installation Instructions Manual page 7

Application
Line voltage terminals
Keyboard Display Module
a
KDM
Data ControlBus
Module™
Remote Reset Module
13 Vdc full wave rectified
transformer power input.
a
The KDM, Data ControlBus Module™ (for remote mounting or communications) or Modbus™ Module must be wired in a
daisy chain configuration, (1(a)-1(a), 2(b)-2(b), 3(c)-3(c)). The order of interconnection of all the devices listed above is
not important. Be aware that modules on the closest and farthest end of the daisy chain configuration string require a
120 ohm (1/4 watt minimum) resistor termination across terminals 1 and 2 of the electrical connectors for connections
over 100 feet (ca. 30 meters).
Ground Type
Earth Ground (Subbase and relay
module)
Signal Ground (KDM, Data
ControlBus Module™
Table 1. Recommended Wire Sizes and Part Numbers.
Recommended Wire Size
14, 16 or 18 AWG (0.75, 1.5 or 2.5 mm
conductor, 600 volt insulation, moisture-resistant
wire.
2
22 AWG (0.34 mm ) two-wire twisted pair with
ground, or five-wire.
2
22 AWG (0.34 mm ) two-wire twisted pair with
ground, or five-wire.
2
22 AWG (0.34 mm ) two-wire twisted pair, insulated
for low voltage.
2
18 AWG (0.75 mm ) wire insulated for voltages and
temperatures for given application.
Table 2. Recommended Grounding Practices.
1. Use to provide a connection between the subbase and the control panel of
the
equipment. Earth ground must be capable of conducting enough current to
blow
the 15A fuse (or breaker) in the event of an internal short circuit.
2. Use wide straps or brackets to provide minimum length, maximum surface
area
ground conductors. If a lead wire must be used, use 14 AWG (2.5 mm
per wire.
3. Make sure that mechanically-tightened joints along the ground path are
free of
nonconductive coatings and protected against corrosion on mating
surfaces.
Use the shield of the signal wire to ground the device to the signal ground terminal
3(c) of each device. Connect the shield at both ends of the daisy chain to earth
ground.
RM7838B,C 7800 SERIES RELAY MODULE
2 TTW60C, THW75C, THHN90C.
) copper
Belden 8723 shielded cable or
equivalent.
Belden 8723 shielded cable or
equivalent.
—
TTW60C, THW75C, THHN90C.
Recommended Practice
7
Recommended Part Numbers
2
) cop-
32-00199—01