JOHNSON CONTROLS
142
FORM 150.27-NM1
ISSUE DATE: 09/30/2015
SECTION 9 – SERVICE AND TROUBLESHOOTING
Analog Inputs – Pressure
Refer to the unit wiring diagram.
Pressure inputs are
connected to the microboard on plugs J7 and J9. These
analog inputs represent varying DC signals corre-
sponding to varying pressures. All voltages are in ref-
erence to the unit case (ground).
System 1 discharge and suction pressures will be con-
nected to J7 of the microboard. System 2 discharge and
suction pressure transducers will be connected to J9 of
the microboard.
The discharge transducers are optional on all units. If
the discharge transducers are not installed, no connec-
tions are made to the microboard and the discharge
pressure readout on the display would be zero.
The suction pressure transducers are standard on all
YCRL’s. The suction pressure transducers have a
range of 0 to 400 PSIG. The output will be linear from
0.5VDC to 4.5VDC over the 400 PSIG (27.5 barg)
range.
TABLE 25 -
PRESSURE TRANSDUCERS
0-400 PSIG SUCTION
PRESSURE
TRANSDUCER
0-650 PSIG DISCHARGE
PRESSURE
TRANSDUCER
PRESSURE
PSIG
VOLTAGE
VDC
PRESSURE
PSIG
VOLTAGE
VDC
0
0.5
0
0.5
50
1.0
81.25
1.0
100
1.5
162.5
1.5
150
2.0
243.75
2.0
200
2.5
325
2.5
250
3.0
406.25
3.0
300
3.5
487.75
3.5
350
4.0
568.75
4.0
400
4.5
650
4.5
Red Wire = 5V, Black wire = 0V, White/Green Wire = signal
TEST POINTS:
Suction Pressure:
System 1: ..................................Microboard J7-10 to J7-9
System 2: ..................................Microboard J9-10 to J9-9
Discharge Pressure:
System 1: ..................................Microboard J7-11 to J7-7
System 2: ..................................Microboard J9-11 to J9-7
The discharge transducers have a range from 0 to
650 PSIG. The output will be linear from 0.5VDC to
4.5VDC over the 650 PSIG (41.25 barg) range. Fol-
lowing is the formula that can be used to verify the
voltage output of the transducer. All voltage reading
are in reference to ground (unit case).
V = (Pressure in PSIG x .01) + .5
or
V = (Pressure in barg x .145) + .5
where V = DC voltage output
Pressure = pressure sensed by transducer
The I/O board connections for the Discharge Transduc-
ers:
System 1 Discharge Transducer
J7-6 = +5VDC regulated supply to transducer.
J7-11 = VDC input signal to the microboard.
See the
formula above for voltage readings that cor-
respond to specific discharge pressures.
J7-7 = +5VDC return
J7-2 = drain (shield connection = 0VDC)
System 2 Discharge Transducer
J9-6 = +5VDC regulated supply to transducer.
J9-11 = VDC input signal to the microboard.
See the
formula above for voltage readings that cor-
respond to specific discharge pressures.
J9-7 = +5VDC return
J9-2 = drain (shield connection = 0VDC)
