Trane Tracer XM70 - Method 2; Binary Inputs: 24 Vac Detect (Methods 1 or 2)

28
BAS-SVX46E-EN
Method 2
General Information Checkout Procedure Measurement
Expected Value
Method 2 is less disruptive to the
system. In voltage mode, the
DMM affects the circuit less.
Additional information is needed
to translate the voltage
measured to current flowing
through the circuit.
Step 1
Measure AC voltage across the
voltage input
VAC ≈ 0.0 V
AC voltage will affect further
measurement
Step 2
Measure DC voltage across the
voltage termination
Refer to the chart below
2.5
3
3.5
4
4.5
1.5
0
0.5
1
2
Measured Voltage Across a Linear Current Input
Linear Current Input–mA
10 124 60 2 16 188 2014
Voltage Measured Across Input–Vdc
Binary Inputs: 24 Vac Detect (Methods 1 or 2)
General Information and Checkout Procedure
Measurement Expected Value
Method 1:
Voltage across binary input measured without reference to chassis
ground.
Measure AC voltage
across the binary input
VAC ≈ 0.0 V (state = ON)
VAC ≈ 24.0 V (state = OFF)
Method 2:
Voltage across binary input measured with reference to chassis
ground. Any connection with chassis ground symbol can serve as a
ground reference for this method.
Measure DC voltage
across the binary input
VAC ≈ 0.0 V (state = OFF)
VAC ≈ 24.0 V (state = ON)
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