York YCAL0014SC, YCAL0080SC manual Service and Troubleshooting, Digital Outputs

Service and Troubleshooting

The suction transducers have a range from 0 to 200 PSIG (13.79 BARG). The output will be linear from .5 VDC to 4.5 VDC over the 200 PSIG (13.79 BARG) range. Following is a 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 .02) + .5

or

V = (Pressure in BARG x .29) + .5

where V = dc voltage input to micro Pressure = pressure sensed by transducer

Following are the microboard connections for the Suc- tion Transducer:

System 1 Suction Transducer

J4-5 = +5VDC regulated supply to transducer.

J4-10 = VDC input signal to the microboard. See the formula above for voltage readings that correspond to specific suction pressures.

J4-1 = +5VDC return

J4-2 = drain (shield connection = 0VDC)

System 2 Suction Transducer

J7-5 = +5VDC regulated supply to transducer.

J7-10 = VDC input signal to the microboard. See the formula above for voltage readings that correspond to specific suction pressures.

J7-1 = +5VDC return

J7-2 = drain (shield connection = 0VDC)

If the optional Suction Transducer is not used on the YCAL0014 - YCAL0060, a Low Pressure switch will be used. Following are the microboard connections for the Low Pressure switch.

System 1 Low Pressure Switch

J4-5 = +5VDC regulated supply to LP switch.

J4-10 = input signal to the microboard. 0VDC = open switch / +5 VDC = closed switch.

J4-2 = drain (shield connection = 0VDC)

System 2 Low Pressure Switch

J7-5 = +5VDC regulated supply to LP switch.

J7-10 = input signal to the microboard. 0VDC = open switch / +5VDC = closed switch.

J7-2 = drain (shield connection = 0VDC)

DIGITAL OUTPUTS

Refer to the unit wiring diagram and Table 46. The digi- tal outputs are located on TB3, TB4, and TB5 of the microboard. ALL OUTPUTS ARE 120VAC with the ex- ception of TB5-3 to TB5-4. TB5-3 to TB5-4 are the con- tacts that can be used for an evaporator pump start sig- nal. The voltage applied to either of these terminals would be determined by field wiring.

Each output is controlled by the microprocessor by switching 120VAC to the respective output connection energizing contactors, evap. heater, and solenoids ac- cording to the operating sequence.

120 vac is supplied to the microboard via connections at TB3-1, TB3-7, TB4-3, and TB4-7. Figure 9 illustrates the relay contact architecture on the microboard.

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