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■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 4.97k or lower.
I
1.7
Z
R ≤
× Z =
× 3.8 = 4.97[kΩ]
I
1.3
R
3.
When the resistor (R) is 2.7k, for example, the power capacity (W) of the resistor (R) becomes 0.308W.
2
2
W = V
÷ R = 28.8
÷ 2700 = 0.308[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 2.7k; and 1 to 2W.
5.
OFF voltage when the resistor (R) is connected becomes 4.74V. This satisfies that the OFF voltage of NZ2MFB1-32D is
5V or lower.
1
1
1
+
2.7[kΩ]
3.8[kΩ]
11 TROUBLESHOOTING
104
11.4 Examples of Troubles with the I/O Module
Input module
24VDC
Resistor
× 3[mA] = 4.74[V]
Iz = 1.7mA
Z = 3.8kΩ
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Table of Contents
Troubleshooting
