Mitsubishi Electric NZ2GN2S1-16D User Manual page 204

■Calculation example
If the switch with LED indicator with maximum leakage current of 3mA when 24VDC external power supply is provided to the
NZ2GN2B1-32D is connected
Leakage current 3mA
1.
The OFF current of NZ2GN2B1-32D is not 1.5mA or lower. Therefore, connect a resistor as shown below.
3mA
I =1.5mA
R
24VDC
2.
To satisfy the condition that the OFF current of NZ2GN2B1-32D is 1.5mA or lower, the current through the connected
resistor should be 1.5mA or higher. From the formula below, the connected resistor (R) is lower than 3.0k.
I : I = Z (Input impedance): R
R Z
I
Z
R ≤ × Z (Input impedance) =
I
R
3.
When the resistor (R) is 2.5k, for example, the power capacity (W) of the resistor (R) becomes 0.332W.
2
W = (Input voltage) ÷ R = 28.8
4.
Because the resistor requires a power capacity that is 3 to 5 times larger than the actual current consumption, the
resistor connected to the terminal should be 2.5k; and 1 to 2W.
5.
OFF voltage when the resistor (R) is connected becomes 4.09V. This satisfies that the OFF voltage of NZ2GN2B1-32D
is 5V or lower.
1
1 1
+
2.5[kΩ] 3.0[kΩ]
11 TROUBLESHOOTING
202
11.5 Examples of Troubles with the I/O Module
Input module
24VDC
I =1.5mA
Z
Input impedance
R
3.0kΩ
1.5
× 3.0 = 3.0[kΩ]
1.5
2
÷ 2500 = 0.332[W]
× 3[mA] = 4.09[V]