Bryant 548J User Manual
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36
Table 14 – RTU--MP Controller Inputs and Outputs
POINT NAME
BACnet OBJECT
NAME
TYPE OF I/O
CONNECTION PIN
NUMBERS
INPUTS
Space Temperature Sensor
sptsens
AI (10K Thermistor)
J20---1, 2
Supply Air Temperature
sat
AI (10K Thermistor)
J2---1, 2
Local Outside Air Temperature Sensor
oatsens
AI (10K Thermistor)
J2---3, 4
Space Temperature Offset Pot
sptopot
AI (100K Potentiometer)
J20---3
Indoor Air Quality
iaq
AI (4---20 ma)
J4---2, 3
Outdoor Air Quality
oaq
AI (4---20 ma)
J4---5, 6
Safety Chain Feedback
safety
DI (24 VAC)
J1---9
Compressor Safety
compstat
DI (24 VAC)
J1---2
Fire Shutdown
firedown
DI (24 VAC)
J1---10
Enthalpy Switch
enthalpy
DI (24 VAC)
J2---6, 7
Humidistat Input Status
humstat
DI (24 VAC)
J5---7, 8
CONFIGURABLE INPUTS*
Space Relative Humidity
sprh
AI (4---20 ma)
J4---2,3 or J4---5,6
Outside Air Relative Humidity
oarh
AI (4---20 ma)
Supply Fan Status
fanstat
DI (24 VAC)
J5---1,2 or J5---3,4 or
J5 5,6 or J5---7,8
Filter Status
filtstat
DI (24 VAC)
Remote Occupancy Input
remocc
DI (24 VAC)
OUTPUTS
Economizer Commanded Position
econocmd
4---20ma
J2---5
Supply Fan Relay State
sf
DO Relay (24VAC , 1A)
J1---4
Compressor 1 Relay State
comp_1
DO Relay (24VAC , 1A)
J1---8
Compressor 2 Relay State
comp_2
DO Relay (24VAC , 1A)
J1---7
Heat Stage 1 Relay State
heat_1
DO Relay (24VAC , 1A)
J1---6
Heat Stage 2 Relay State
heat_2
DO Relay (24VAC , 1A)
J1---5
Power Exhaust Relay State
aux_2
DO Relay (24VAC , 1A)
J11---3
Dehumidification Relay State
humizer
DO Relay (24VAC, 1A)
J11---7, 8
LEGEND
AI --- Analog Input
AO --- Analog Output
DI --- Discrete Input
DO --- Discrete Output
* These inputs (if installed) take the place of the default input on the specific channel according to schematic.
Parallel pins J5---1 = J2---6, J5---3 = J1---10, J5---5 = J1---2 are used for field---installation.
Refer to the input configuration and accessory sections for more detail.
The RTU--MP controller requires the use of a Bryant
space sensor. A standard thermostat cannot be used with
the RTU--MP system.
Supply
Air
Temperature
(SAT)
Sensor
—
On
FIOP--equipped 548J unit, the unit is supplied with a
supply--air temperature (SAT) sensor (33ZCSENSAT).
This sensor is a tubular probe type, approx 6--inches
(153 mm) in length. It is a nominal 10--k ohm thermistor.
See Table 15 for temperature--resistance characteristic.
The SAT is factory--wired. The SAT probe is wire--tied to
the supply--air opening (on the horizontal opening end) in
its shipping position. Remove the sensor for installation.
Re--position the sensor in the flange of the supply--air
opening or in the supply air duct (as required by local
codes). Drill or punch a
1
/
2
--in. (12.7 mm) hole in the
flange or duct. Use two field--supplied, self--drilling
screws to secure the sensor probe in a horizontal
orientation. See Fig. 49.
SUPPLY AIR
RETURN AIR
SUPPLY AIR
TEMPERATURE
SENSOR
ROOF
CURB
C08200
Fig. 49 -- Typical Mounting Location for Supply Air
Temperature (SAT) Sensor on Small Rooftop Units
548J