Network Adapter - Honeywell TB7200 Series Integration Manual

NETWORK ADAPTER

The polarity of the connection to the cable is important. From one module to the other it is important that the same colored wire
be connected to "plus" or "+" and the other colored wire be connected to the "minus" or "-". Figure 5 shows the proper MS/TP
connections and the location of the Status LED. This Status LED may help to troubleshoot network problems.
Fig. 5. Correct MS/TP connections and location of a Status LED on a BACnet module
IMPORTANT NOTE: The Ref terminal should NEVER be used to wire shields. The 2 shields from each feed of the network
connection to a thermostat should be wired together in the back of the thermostat and properly protected to prevent any
accidental connection to the ground.
The joined shield connection should then be grounded at a SINGLE point on the whole segment. More than one ground
connection to a shielded wire may induce ground loop noises and affect communication.
Network Adapter Status LED
Table 3 shows the different possibilities with the Status LED behavior for a BACnet module.
Condition of the Status LED
• 1 short blink
• 2 short blink (no wires
connected to the module)
• 2 short blink (wires connected
to the module)
• 2 short blinks and a longer blink
(wires connected to the
module)
• Right after power is applied: 2
long blinks and then no blinking
BACNET INTEGRATION MANUAL FOR TB7200 & TB7300 SERIES THERMOSTATS
Table 3. Status LED condition and possible solutions.
Possible Cause
BACnet communication NOT active at
default MAC address = 254
The right module has been installed on
the right thermostat model
Module is not at the same baud rate as
the network
The module has detected the presence
of a network
Polarity has been reversed at the
module
Change MAC address to another
value from 0 to 127
N/A
Power off and on the thermostat
N/A
Reverse polarity at the module
7
Solution
63-4524—03