York Sun Premier GZA1M Series, Start-Up & Operation

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YORK
Start-Up & Operation Guide | 5587001-YSG-A-520
95
Operation
Communication Components
FC BUS Terminal Block
An FC bus connects to BACnet MS/TP, Modbus, or N2
devices. Third party BACnet MS/TP or Modbus devic-
es can also be connected to the FC bus. Units shipped
with a BACnet IP card cannot support BACnet MS/TP,
Modbus, or N2 on the FC bus. Unplug the BACnet IP
card to support other protocols.
The FC bus terminal block is a removable, 4-terminal plug
that fits into a board-mounted jack. Wire the removable
FC bus terminal block plugs on the main control board
and other control boards in a daisy chain configuration
using a 3-wire twisted, shielded cable as shown in
Figure
40
. See
Table 27 on page 96
for more information.
Terminating Device
on FC Bus Segment
Daisy Chained Device
on FC Bus Segment
FC Bus
Terminal Block Plugs
To Next
Device on
the FC Bus
Segment
To Next Device
on the FC Bus
Segment
Stranded 3-Wire Twisted Shielded Cable
Isolated Shield
Connection Terminal
+ - COM SHLD + - COM SHLD
NOTE: The FC bus shield (SHLD) terminal is isolated and can be
used to connect (daisy chain) the shields for FC bus wiring.
LD28037
Figure 40: FC Bus Daisy Chain
Terminating Device
on SA Bus
Daisy Chained
Device on SA Bus
SA Bus
Terminal Block Plugs
To Next Device
on the SA Bus
To Next Device
on the SA Bus
Stranded 4-Wire (Two Twisted Pair) Shielded Cable (One twisted
pair is the + and - leads, and the second pair is COM and SA PWR)
Cable Shield
Connection
+ - COM SA
PWR
+ - COM SA
PWR
NOTE: The SA PWR terminal supplies 15 VDC. The SA PWR termi-
nal can be used to connect (daisy chain) the 15 VDC power
leads on the SA bus.
LD28038
Figure 41: SA Bus Daisy Chain
SA BUS Terminal Block
The SA bus connects to end point devices, such as
network thermostats and network sensors.
The SA bus terminal block is a removable, 4-terminal
plug that fits into a board-mounted jack. Wire the re-
movable SA bus terminal block plugs on the controller
and other SA bus devices in a daisy-chain configura-
tion using a 4-wire twisted, shielded cable as shown in
Figure 41
. See
Table 27 on page 96
for more infor-
mation.
MS/TP Bus Cable Recommendations
The MS/TP bus supports much higher baud rates
than the N2 bus. Higher baud rates make the MS/
TP bus less fault tolerant and less immune to in-
terference from inductive noise sources that may
be present in the application environment.
Modbus Terminal Block
The Modbus connects to the burner control board and
the VFDs installed in the unit.
EQ BUS Terminal Block
The EQ bus connects to all installed control boards.
BACnet IP Terminal Block
The BACnet IP board is available as an option. ETH1
and ETH2 ports are available for daisy chaining from
a central Ethernet switch. Daisy chaining is not neces-
sary for Bacnet IP.
BACnet IP Cable Recommendations
Category 5 (Cat 5, Cat 5e, and Cat 6) cables
should be used for BACnet integration.
End of Line (EOL) Switch
The integral EOL switch must be set to ON, if the unit
is located at either end of each bus segment on a FC
bus.
Daisy-chained RS485-protocol networks typically re-
quire some type of EOL termination to reduce interfer-
ence caused by signal reflection that occurs when data
transmissions reach the end of a bus segment and
bounce back on the segment. The high baud rates on
MS/TP bus applications require robust EOL termina-
tion and strict adherence to the EOL termination rules.
Review EOL termination requirements for third party
MS/TP devices and network thermostats.