18
OMM 1008-1
Unit Controller
Table 2, Unit Controller, Analog Inputs
#
Description
Signal Source
Range
1
Reset of Leaving Water Temperature
4-20 mA Current
0-(10 to 80°F)
2
Entering Evaporator Water
Temperature
NTC Thermistor (10k@25°C)
-58 to 212°F
3
Entering Condenser Water
Temperature
NTC Thermistor (10k@25°C)
-58 to 212°F
4
Leaving Condenser Water Temperature
NTC Thermistor (10k@25°C)
-58 to 212°F
5
Liquid Line Refrigerant Temperature
NTC Thermistor (10k@25°C)
-58 to 212°F
6
Demand Limit
4-20 mA Current
0-100 %RLA
7
Evaporator Water Flow
4 to 20 mA Current
0 to 10,000 gpm
8
Condenser Water Flow
4 to 20 mA Current
0 to 10,000 gpm
9
Refrigerant Leak Sensor
4 to 20 mA Current
0 to 100 ppm
10
Leaving Evaporator Water Temperature
NTC Thermistor (10k@25°C)
-58 to 212°F
Table 3, Unit Controller, Digital Inputs
#
Description
Signal
Signal
1
Unit OFF Switch
0 VAC (Stop)
24 VAC (Auto)
2
Remote Start/Stop
0 VAC (Stop)
24 VAC (Start)
3
Not Used
4
Evaporator Water Flow Switch
0 VAC (No Flow)
24 VAC (Flow)
5
Condenser Water Flow Switch
0 VAC (No Flow)
24 VAC (Flow)
6
Manual Off
0 VAC (Off)
24 VAC (Auto)
7
Evaporator Water Flow Switch
0 VAC (No Flow)
24 VAC (Flow)
8
Condenser Water Flow Switch
0 VAC (No Flow)
24 VAC (Flow)
Table 4, Unit Controller, Digital Outputs
#
Description
Load
Output OFF
Output ON
1
Evaporator Water Pump #1
Pump Contactor
Pump OFF
Pump ON
2
Evaporator Water Pump #2
Pump Contactor
Pump OFF
Pump ON
3
Condenser Water Pump #1
Pump Contactor
Pump OFF
Pump ON
4
Condenser Water Pump #2
Pump Contactor
Pump OFF
Pump ON
5
Tower Fan #1
Fan Contactor
Fan OFF
Fan ON
6
Tower Fan #2
Fan Contactor
Fan OFF
Fan ON
7
Spare
8
Alarm
Alarm Indicator
Alarm OFF
Alarm ON
9
Tower Fan #3
Fan Contactor
Fan OFF
Fan ON
10
Tower Fan #4
Fan Contactor
Fan OFF
Fan ON
11
Compressor Off Emer.
Solenoid
Circuit Breaker
ON
Circuit Breaker
OFF
Table 5, Unit Controller, Analog Outputs
#
Description
Output Signal
Range
1
Cooling Tower Bypass Valve Position
0 to 10 VDC
0 to 100% Open
2
Cooling Tower VFD Speed
0 to 10 VDC
0 to 100%
3
EXV signal to IB Valve Control Bd.
0 to 10 VDC
0 to 100%
4
Y3 Electronic Expansion Valve
0 to 10 VDC
0 to 100% Open
Unit Controller Setpoints
The following parameters are remembered during power off, are factory set to the
Default
value, and can be
adjusted to any value in the
Range
column.
The “Type” column defines whether the setpoint is part of a coordinated set of duplicate setpoints in different
controllers. There are three possibilities as given below:
N
= Normal setpoint - Not copied from, or copied to, any other controller.
M
= Master setpoint - Setpoint is copied to all controllers in the “Sent To” column.
S
= Slave setpoint - Setpoint is a copy of the master setpoint (in the unit controller).
