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Operation
6
2.3.1. Relay
Contacts
FAN #1 – Power for Fan #1 is connected to TB2-3 (N) and TB2-4 (L). Fan #1 is connected to
TB2-1 and TB2-2. There is a 30 A fuse in series with TB2-1.
FAN #2 – Power for Fan #2 is connected to TB2-7 (N) and TB2-8 (L). Fan #2 is connected to
TB2-5 and TB2-6. There is a 30 A fuse in series with TB2-5. Note that the Fan #2 circuit is
electrically separate from Fan #1.
ALARM – SPDT (form C) contacts are provided at TB1-1, -2, and -3 to indicate an alarm
condition. This relay is usually set to be energized in the normal state so that the power OFF
state will cause an alarm (failsafe). The normal state can be changed by the User Configuration
software via the USB port.
NOTE: Under failsafe conditions below set point, TB1-1 and -2 are closed, and TB1-2 and
-3 are open. Under failsafe alarm conditions, TB1-1 and -2 will open, and TB1-2
and -3 will close. The operation of this relay can be changed to be non-failsafe,
the opposite of that described above, through the software configuration.
TRIP – SPDT (form C) contacts are provided at TB1-4, -5, and -6 to indicate that the
temperature being monitored has reached the trip state. This relay is usually set to be de-
energized n the normal (non-failsafe) state. The normal state of the relay can be changed by
the User Configuration software via the USB port.
NOTE: Under non-failsafe conditions below the set point, TB1-4 and -5 are open, and
TB1-5 and -6 are closed. Under non-failsafe trip conditions, TB1-4 and -5 will
close, and TBI-5 and -6 will open
The operation of this relay can be changed to be
failsafe, the opposite of that described above, through the software
configuration.
RELAY 4 (form C) contacts are provided at TB1-7, -8, and -9 to indicate that the temperature
being monitored has exceeded the set point. This AUX relay is usually set to be de-energized in
the normal (non-failsafe) state. The normal state of the relay can be changed by the User
Configuration software via the USB port.
NOTE: Under non-failsafe conditions below the set point, TB1-7 and -8 are open, and
TB1-8 and -9 are closed. When the set point is exceeded, TB1-7 and -8 will close,
and TBI-8 and -9 will open. The operation of this AUX relay can be changed to be
failsafe, the opposite of that described above, through the software
configuration.
RELAY 5 (form C) contacts are provided at TB1-10, -11, and -12 to indicate that the temperature
being monitored has exceeded the set point. This AUX relay is usually set to be de-energized in
the normal (non-failsafe) state. The normal state of the relay can be changed by the User
Configuration software via the USB port.
NOTE: Under non-failsafe conditions below the set point, TB1-10 and -11 are open, and
TB1-11 and -12 are closed. When the set point is exceeded, TB1-10 and -11 will
close, and TBI-11 and -12 will open. The operation of this AUX relay can be
changed to be failsafe, the opposite of that described above, through the
software configuration.
