FORM 100.50-NOM7 (808)
71
JOHNSON CONTROLS
6
The controller will wait 30 seconds from the time of the
above control actions and then restart the Supply Fan
by setting the Supply Fan output to ON (high). Normal
heating or cooling operation will begin.
VFD Bypass operation will continue until the VFD By-
pass input goes low (0 volts). The unit will then return
to normal operation.
ANALOG INPUT OPERATION
This section describes the control operation of the (13)
thirteen analog inputs. These inputs will be used by the
control to monitor and respond to unit temperatures,
pressures, enthalpy, etc. The connection “layout” for the
IO (inputs/outputs) is shown in the MOD-DCU connec-
tion map in Figure 20. Notice that the figure shows the
Jack connection designated by “J”, and the pin number
located on the inside of the board diagram. The input
or output designations are shown on the outside of the
figure. For example, J11 – 1 is jack eleven - pin 1 and
is AI5 (analog input 5). J13 – 3 is jack 13 - pin 3 and is
AI14 (analog input 14). For example, AI5 (J11 – 1) is the
input for Outside Air Relative Humidity, and is used as
part of the economizer control scheme. AI13 (J13 – 1)
is the input for Supply Air Temperature, and is used for
control in both the CV and VAV control schemes. The
analog inputs are also in the I/O tables in Table 17 with
descriptions for each input.
Return, Outside, Supply Air and Slab
Temperature
The temperature sensors are RTD sensors that can be
checked with an ohmmeter. Table 8 provides the resis-
tance values for a given temperature in °F.
Duct Pressure Transducer
The duct pressure transducer is mounted in the return air
section of the unit on the panel wall. The purpose of this
transducer is to sense and convert the static pressure in the
supply-side of the duct to a DC voltage. The DC voltage
is then sent to the unit controller and compare against the
Duct Static Pressure setpoint
. The control wiring is fac-
tory wired, but pneumatic tubing must be field supplied
and installed
(refer to Installation section in manual).
The duct pressure transducer measures differential pres
-
sure between the pressure in the duct and atmospheric
pressure. When verifying transducer operation, the
technician must insert a tee into the pneumatic tubing
to connect a manometer and verify the pressure being
applied to the transducer. Once this pressure is known,
a comparison can be made of the duct pressure vs. out-
put volts DC from the transducer. Table 11 shows the
relationship between the pressure applied to the duct
pressure transducer and the output voltage.
Building Pressure Transducer
The building pressure transducer is located in the return
air section of the unit. The purpose of this transducer is
to sense and convert the static pressure in the building
to a DC voltage. The DC voltage is then sent to the unit
controller and compare against the
Building
Pressure
setpoint
. The control wiring from the transducer is fac-
tory wired, but pneumatic tubing must be field supplied
and installed
(refer to Installation section in manual).
The building pressure transducer measures differential
pressure between the pressure in the building and at-
mospheric pressure. When verifying transducer opera-
TABLE 8 – TEMPERATURE SENSOR RESISTANCE
TABLE
TEMPERATURE SENSOR OUTPUT TABLE
TEMP. OHMS TEMP. OHMS
°F RESISTANCE °F RESISTANCE
-20
751
80
1030
-10
777
90
1060
0
803
100
1090
10
830
110
1121
20
858
120
1152
30
885
130
1184
40
914
140
1216
50
942
150
1248
60
971
160
1281
70 1000 170 1314
TABLE 9 – *DUCT PRESSURE TRANSDUCER
OUTPUT TABLE
DUCT PRESSURE TRANSDUCER OUTPUT TABLE
DIFFERENTIAL INPUT
OUTPUT VOLTAGE
PRESSURE - IWG
- VDC
0.5 0.25
0.5
1.0 0.50
1.0
1.5 0.75
1.5
2.0 1.00
2.0
2.5 1.25
2.5
3.0 1.50
3.0
3.5 1.75
3.5
4.0 2.00
4.0
4.5 2.25
4.5
5.0 2.50
5.0
* 2.5 IWC Duct Transducer Available for FlexSys Option
Summary of Contents for J Series
Page 85: ...FORM 100 50 NOM7 808 85 JOHNSON CONTROLS 6 ELECTRICAL NOTES AND LEGEND LD13862 ...
Page 87: ...FORM 100 50 NOM7 808 87 JOHNSON CONTROLS 6 LD13864 ...
Page 88: ...JOHNSON CONTROLS 88 FORM 100 50 NOM7 808 Service OPTI CONVERSION TO 25 40 TON LD13854 ...
Page 89: ...FORM 100 50 NOM7 808 89 JOHNSON CONTROLS 6 LD13865 ELEMENTARY DIAGRAM ALL UNITS ...
Page 91: ...FORM 100 50 NOM7 808 91 JOHNSON CONTROLS 6 ELEMENTARY DIAGRAM GAS HEAT 25 40 TON 575V LD13861 ...