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1. Active Sensor
Rquires three wires; V+, GND and signal output.
2. Passive Sensor
Requires two wires; V+ and signal output.
Input Connections, Discrete Sensors (VX12i)
Discrete type sensors offer only an indication of “true” or “false” and no information in between. Typical
examples include liquid presense detection sensors, manual and proximity switches, door and window
switches, etc.
Passive Sensors
Passive sensors are simple, typically mechanical sensors that manipulate a physical switch (dry contact) to
close a circuit. Passive sensors do not have any electronics on board and simply pass through the signal
voltage when the condition is true. Passive sensors only require two wires; the signal voltage and the sensor
output.
Active Sensors
Active sensors have electronics on board and require both a power and ground wire to operate the sensor,
plus a third wire to carry the output signal of the sensor.
O8
O7
GND
O6
O4
O2
IN4
IN2
+5V
O5
GND
O3
GND
O1
GND
IN3
GND
IN1
GND
GND
1
2
Passive Discrete Sensor
(Float Switch, Dry Contact)
Active Discrete Sensor
(SXL Liquid Detection Sensor)
