Omron CPM1A operation manual Inductive Loads, Crimp Connectors

Wiring and Connections Section 3-4

Leakage Current (24 VDC) A leakage current can cause false inputs when using 2-wire sensors (proximity switches or photoelectric switches) or limit switches with LEDs.

False inputs won’t occur if the leakage current is less than 1.0 mA (2.5 mA for IN00000 to IN00002), but if the leakage current exceeds these values, insert a bleeder resistor in the circuit to reduce the input impedance, as shown in the fol- lowing diagram.

2-wire sensor, etc.

Input power
supply
Bleeder resistor	R

CPM1A

I:Device’s leakage current (mA)

R:Bleeder resistance (kΩ )

W:Bleeder resistor’s power rating (W)

LC: CPM1A’s input impedance (kΩ )

IC: CPM1A’s input current (mA)

EC: CPM1A’s OFF voltage (V) = 5.0 V

R +	LC	5.0	kW max.	W +	2.3	W min.
	I	LC–5.0			R

The equations above were derived from the following equations:

		R			Input voltage (24)
					Input Current (IC)
	I						x OFF voltage (EC : 5.0)
		R )		Input voltage (24)
				Input Current (I		)
						C
	W y		Input voltage (24)			Input voltage (24) tolerance (4)
					R
	Refer to 2-1-3 I/O Specifications for details on the values LC, IC, and EC.
	The input impedance, input current, and OFF voltage may vary depending on the
	input being used. (IN00000 through IN00002 have different values.)
Inductive Loads	When connecting an inductive load to an input, connect a diode in parallel with
	the load. The diode should satisfy the following requirements:

1, 2, 3... 1. Peak reverse-breakdown voltage must be at least 3 times the load voltage.

2. Average rectified current must be 1 A.

Diode

IN

CPM1A

COM

Crimp Connectors

!Caution Always use crimp connectors for the CPM1A’s power lines and I/O lines or else use a solid wire (instead of a stranded wire). Do not connect bare stranded wires directly to terminals. Bare stranded wires connected directly to the terminal can cause a fire.

Use M3 terminal screws and tighten the screws securely (0.5 N S m).

Fork terminal	Ring terminal
6.2 mm max.	6.2 mm max.

The recommended wire size for solid wires is 0.4 to 1.2 mm (AWG26 to AWG18).

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