Please advise possible causes and countermeasures about electrical malfunctions of Photo IC type Photomicrosensors.
The majority of the electrical failures of Photomicrosensors are caused by electrical stresses such as overcurrent and overvoltage.
The followings are possible causes of electrical failure of built-in type Photomicrosensors.
- The power supply voltage or current exceeds the specified rating.
- The output transistor is connected without a load.
- Reverse voltage is applied due to wrong wiring during assembly.
- Power line surge.
- There is the induction from high voltage line or power line which are wired parallel to the wiring of the sensor.
- A small inductive load such as a relay is used.
- Destroyed by static electricity during assembly.
Take the following measures for design, assembly and operation.
- Design the circuit so that it does not exceed the specified rating.
- As the internal element may burst or burn out, apply a load when wiring.
- If reverse voltage is applied to Photomicrosensors due to incorrect wiring during assembly, such as a wrong connector type, it may cause a failure even instantaneously. Turn on the power after sufficient confirmation.
- If there is a surge in the power supply line, connect a Zener diode (30 to 35V) or capacitor (0.1 to 1μF) according to the operating environment. Confirm that the surge will go out before operation.
- If the wiring of Photomicrosensors is connected to the same wiring duct for high voltage line and/or power line, the induction may cause failure or malfunction. Use a separate wiring or a single wiring, and confirm that there is no induction.
- The load cannot be a relay.
- Photomicrosensors may be damaged by static electricity during assembly and mounting. Assemble and mount in an environment where static electricity is prevented.
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