Omron FQM1-CM001 Wiring Precautions, Section, Precautions when Connecting a Two-wireDC Sensor

Wiring Precautions Section 3-6

NPN current output

+

Current
regulator	Output
	7 mA	Sensor
	0 V	power
		supply
PNP current output

IN DC input

+

COM +

Precautions when Connecting a Two-wire DC Sensor

1,2,3...

+Sensor power supply

Output	IN	DC input
7 mA	COM
0 V

Voltage output

+	COM +
Output	IN	DC input
0 V	Sensor
	power
	supply

•The circuit below should NOT be used for I/O devices having a voltage output.

+	Sensor
	power
		DC input
	supply

Output	IN
0 V	COM	−

When using a two-wire sensor with a 24-V DC input device, check that the fol- lowing conditions have been met. Failure to meet these conditions may result in operating errors.

1.Relation between the FQM1 ON voltage and the sensor residual voltage:

VON ≤ VCC – VR

2.Relation between the FQM1 ON current and sensor control output (load current):

IOUT (min) ≤ ION ≤ IOUT (max.)

ION = (VCC – VR – 1.5 [FQM1 internal residual voltage])/RIN

If ION is smaller than IOUT (min), connect a bleeder resistor R. The bleeder resistor constant can be calculated as follows:

R ≤ (VCC – VR)/(IOUT (min.) – ION)

Power W ≥ (VCC – VR)2/R ⋅ 4 [allowable margin]

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