Product Overview

FlexStat (General) 15 Application Guide, Rev S
MS/TP EOL (End-Of-Line) Termination
The controllers/thermostats on the physical ends of an EIA-485 wiring
segment must have end-of-line termination installed for proper network
operation. If a FlexStat is at the physical end of the MS/TP network line,
set both the EOL termination switches to On (to the right/up) on the
back of the circuit board. If not on the end, ensure that both switches are
O (left/down).
See the FlexStat Operation Guide for more conguration and operation
details.
MS/TP Network, Shield, and Ground Connections
   
MS/TP Network End-Of-Line Termination
BAC-12xxxx EOL/Pull-Up Switch Positions
10K Ohm
0-12 VDC
Input Pull-Up Switches
EOL
Switches
ON
OFF
Switch Pushed Up
Pushed Down
IN2 IN3 IN4 IN7 IN8
IN9
BAC-13xxxx/14xxxx Switch Positions
10K Ω
0-12 V
Input Pull-Up Switches
ON
OFF
Switch
Pushed
Right
IN2
IN3
IN4
IN7
IN8
IN9
NOTE: 10K Ω inputs
are configurable for
Type II or Type III
thermistors in
FlexStat’s menu.
NOTE: EOL = End
Of Line of BACnet
MS/TP network.
EOL Switches
Switch
Pushed
Left
+B
–A
Middle
FlexStats
Shield Wire Connected to Ground on One End Only
EOL
FlexStat
+B
–A
+B
–A
EOL
FlexStat
For MS/TP (EIA-485) communications, connect the –A terminals in
parallel with all other –A terminals on the network and the +B terminals
in parallel with all other +B terminals. Connect the shields of the cable
together at each device. Use a wire nut or the S terminal in KMC BACnet
controllers. (FlexStats, however, do not have an S terminal.) Connect the
cable shield to a good earth ground at one end only.
NOTE: On other KMC controllers, the S terminal is provided as a con-
necting point for the shield. The terminal is not connected to
the ground of the controller. When connecting to controllers
from other manufacturers, verify the shield connection is not
connected to the controller’s ground.