Mitsubishi Electric NZ2MFB2-16A User Manual page 85

■Calculation example
If the switch with LED indicator with maximum leakage current of 3mA when 24VDC is supplied to the NZ2MFB1-32D is
connected
Leakage current 3mA
1.
The OFF current of NZ2MFB1-32D is not 1.7mA or lower. Therefore, connect a resistor as shown below.
3mA
I = 1.3mA
R
24VDC
Z: Input impedance
2.
To satisfy the condition that the OFF current of NZ2MFB1-32D is 1.7mA or lower, the current through the connected
resistor should be 1.3mA or higher. From the formula below, the connected resistor (R) is lower than 4.97k.
I 1.7
Z
R ≤
× Z = × 3.8 = 4.97[kΩ]
I 1.3
R
3.
When the resistor (R) is 3.9k, for example, the power capacity (W) of the resistor (R) becomes 0.179W.
÷ ÷
2 2
W = V R = 26.4 3900 = 0.179[W]
V: Input voltage
4.
Because the resistor requires the power capacity of 3 to 5 times as large as the actual current consumption, the resistor
connected to the terminal should be 3.9k; and 1 to 2W.
5.
OFF voltage when the resistor (R) is connected becomes 5.77V. This satisfies that the OFF voltage of NZ2MFB1-32D is
8V or lower.
1
× 3[mA] = 5.77[V]
1 1
+
3.9[kΩ] 3.8[kΩ]
Input module
24VDC
Iz = 1.7mA
Resistor
Z = 3.8kΩ
11 TROUBLESHOOTING
11.4 Examples of Troubles with the I/O Module
11
83