B5WC

7

Countermeasures for Switching Power Supplies

Take either of the following countermeasures as required if

connecting a modulated-light sensor to a switching power supply.

1. Attach a capacitor (e.g., aluminum electrolytic capacitor) of 10 μF

min. as close as possible to the sensor when wiring.

(Use a capacitor with a dielectric strength that is at least twice the

sensor's power supply voltage. Do not use tantalum capacitors. A

short-circuit may cause the capacitor to ignite due to the large

current flow.)

2. Connect to the 0-V line of the power source or connect by way of

a capacitor (approx. 0.47 μF) at the point closest to the sensor to

reduce the impedance of the sensor mounting base so that it is

difficult for inductive noise to enter the mounting base.

3. Connect the noise filter terminal (neutral terminal to ACG) of the

switching power supply to the case (FG) and 0-V terminal of the

power supply.

The line connected as mentioned above should be grounded or

connected to the mounting base to ensure stable operation.

(Recommended by power supply manufacturers.)

Countermeasures to Handle Inductive Noise

Insert a plastic insulator of approximately 10 mm between the sensor

and the mounting base.

Effects of Inductive Noise

When there is inductive noise in the sensor mounting frame (metal),

the output of the sensor may be affected.

In this case, ensure that there is no electrical potential difference

between the sensor 0-V terminal and the sensor mounting frame

(metal).

Or, put a 0.47-μF capacitor between the 0-V terminal and the frame.

● Other precautions

1. Do not mount the sensor in the following places because doing so

may cause malfunction or failure.

1) Place exposed to a lot of dust or oil mist

2) Place exposed to a lot of corrosive gas

3) Place directly or indirectly exposed to splashes of water, oil, or

chemicals

4) Outdoors or place exposed to intensive light such as direct

sunlight

2. The sensor may be dissolved by exposure to organic solvents,

acid, alkali, aromatic hydrocarbon, and chlorinated aliphatic

hydrocarbon solvents, causing deterioration in the characteristics.

Do not expose the sensor to such chemicals.

3. An output pulse may occur when the power supply is turned ON

due to the power supply environment and other influences. Use

the sensor in the stable ready-for-detection state reached in 100

ms after turning on the power supply.

4. When the number of averaging times is set to a low value,

variations in the RGB output values may increase due to A/D

conversion errors, noise, and other factors. We recommend

checking the RGB output values multiple times.

5. If the sensor is used outside the power supply voltage range, set

the power to OFF (0 V) once because there is the possibility of

unexpected operation.

6. If foreign matter has adhered to the lens, the output voltage may

vary. When removing foreign matter from the lens, take care not to

touch the lens with a hand, etc. so as to prevent it from getting

scratched or dirty.

7. Use a power supply of max. 15 W for the power supply connected

to this sensor because the internal circuit does not have a safety

device.

Vcc

GND

SDA

SCL

10 μF min.

Sensor

Extension cable

2 m max.

0 V

G

C

(0.47 μF)

Switching

Power Supplies

Mounting

base

Sensor

V

Mounting

base

Sensor

Sensor

Power

Supplies

G

0 V

ACG

FG

Grounding

Switching Power Supplies

Input

V

Sensor

Mounting

base

Power

supply

5 V

0 V

0.47 μF