5567611-BIM-B-1218
46
Johnson Controls Ducted Systems
Smart Equipment™ economizer board - SA bus details
Location
Board
label
Cover
label
Description
Function and comments
C
1
C
COM
Common for SA BUS power and
communication circuits
EconCtrlr parameter reports UCB-to-economizer board SA bus
communication status. Negative of the SA BUS communication
circuit to the UCB. Through the unit wiring harness, may continue on
to the 4-stage board and/or fault detection & diagnostics board
–
–
Communication for SA BUS devices
EconCtrlr parameter reports UCB-to-economizer board SA BUS
communication status. Positive of the VDC (typically, a
fluctuating 1.5 to 3.5 volts reading to C; at least 0.25 volts lower
than +) SA BUS communication circuit to the UCB. Through the
unit wiring harness, may continue on to the 4-stage board and/or
fault detection & diagnostics board
+
+
Communication for SA BUS devices
EconCtrlr parameter reports UCB-to-economizer board SA BUS
communication status. Positive of the VDC (typically, a
fluctuating 1.5 to 3.5 volts reading to C; at least 0.25 volts higher
than –) SA BUS communication circuit to the UCB. Through the
unit wiring harness, may continue on to the 4-stage board and/or
fault detection & diagnostics board
1. When wiring the unit and other devices using the SA Bus and FC Bus, see Table 32.
Smart Equipment™ economizer board - analog outputs
Location
Board
label
Cover
label
Description
Function and comments
D
J4
EX VFD
2-10 VDC positive output for the modulating
power Exhaust fan Variable Frequency Drive/
discharge damper modulating power exhaust
actuator
ExFanVFD parameter reports output status (0-100%) when
ExFType selection is Variable Frequency Fan; EAD-O parameter
reports output status (0-100%) when ExFType selection is
Modulating Damper. Used to ramp the power exhaust fan VFD/
position the discharge damper actuator.
COM
24 VAC common/0-10 VDC negative for the
power exhaust variable frequency drive/
discharge damper modulating power exhaust
actuator
Connects through circuit trace to 24V~ IN pin COM
24V~
24 VAC hot supplied for the discharge damper
modulating power exhaust actuator and
economizer actuator
Connects through circuit trace to 24V~ IN pin HOT
ECON
2-10 VDC output for the Economizer actuator
Econ parameter reports output status (0-100%). Used to position
the economizer actuator for minimum position, free cooling,
demand ventilation, cooling economizer loading and purge
functions
COM
24 VAC common/0-10 VDC negative for
economizer actuator
Connects through circuit trace to 24V~ IN pin COM
