Sensor Integration with Wireless I/O

The sensor compares the measured value with its local threshold. Its relay contact, or a signal relay driven by its output, switches the wireless module's digital input. The wireless system transfers that state to a remote or linked relay output.

This arrangement transfers alarm states. Continuous measurement values and remote sensor setpoint changes require a separate interface.

Connection Paths

Sensor output	Connection to the wireless digital input
Electrically isolated relay contact	Sensor contact between DI and COM
PNP output	Sensor output to a compatible signal relay; relay dry contact between DI and COM
NPN open collector	Direct wiring requires compatible sensor and module electrical specifications

Y401/Y402/Y403 DI accepts contact closures. Keep powered signals and supply voltage off DI. The 9–36 V DC rating applies to the module's power supply, not its digital inputs.

PNP Through a Signal Relay

Sensor PNP output -> compatible signal relay input
Relay dry contact -> wireless module DI and COM
Wireless link    -> receiving module relay output

For a compatible DC relay input, the PNP output supplies the positive control signal and the relay input return goes to the sensor's 0 V. Follow the relay's terminal diagram and polarity. Wire its isolated contact to DI and COM.

For two independent alarms, use two interface channels:

Sensor state	Interface contact	Wireless input
Alarm 1	Signal relay 1 dry contact	DI1 and COM
Alarm 2	Signal relay 2 dry contact	DI2 and COM

Choose the relay's NO/NC contact and the sensor's output polarity for the required receiving-output state.

Relay Selection

Match the relay input voltage and current to the sensor output. Allow for starting current, off-state leakage, output voltage drop, and transient suppression. Check whether the sensor's current rating applies per channel or to the combined outputs.

For a sensor output limited to 50 mA, leave current headroom for the relay input. For example, a 24 V input consuming 0.2 W draws about 8.3 mA in steady operation; its starting current and switching characteristics still need to match the sensor.

Select contacts rated for the DI's small switching load, including the minimum load. A high maximum current rating alone is insufficient. Observe polarity on relay modules with built-in suppression diodes.

Choose the Wireless Channels

Wireless module	Alarm channels and topology
Y401-11-L	One independent state between two points
Y401-22-L	Two independently transmitted states between two points
Y401-44-L	Up to four corresponding digital states
Y402-11-L	One corresponding state in a master/slave system
Y402-44-L	Multiple corresponding channels; slave inputs aggregate by channel
Y402-41-L	Assigned one-channel slaves mapped to separate master channels
Y403-11-L	One local input in a linked multi-node alarm

A one-channel slave accepts one alarm state. Use one DI for a combined window alarm or two DIs for separate high and low alarms at the sensor location.

In Y401, the remote output resets when its paired input opens. In Y402-11-L/-44-L, the master output resets once the slave inputs for that channel are all open. In Y403-11-L, the linked outputs reset once all node inputs are open. See the Wireless I/O User Manual for operating details.

Commissioning

1. Check the sensor configuration, cable pinout, relay input, and wireless model.
2. Set and save the threshold, reset value, mode, polarity, and fault response.
3. Change the measured value through the alarm and reset points.
4. Observe the sensor output, interface contact, local DI, and receiving DO.
5. Test each independent output and both sides of a window where applicable.
6. Cycle power and check the saved settings and startup output state.
7. Test the multi-node reset conditions and any defined fault behavior.

Measure the total response time through the sensor, any interface relay, and the wireless modules before using the system for control. The wireless link is not an emergency-stop or personnel-safety control path.

Related document: Sensors.