Examples Of Troubles With The I/O Module; Troubleshooting For Input Circuit - Mitsubishi Electric NZ2GN2S1-32D User Manual

11.5

Examples of Troubles with the I/O Module

Troubleshooting for input circuit

This section describes the troubleshooting for input circuit.
An input signal does not turn off No.1
■Cause
Drive by a switch with LED indicator
Leakage current
■Action
Connect an appropriate resistor as shown below so that a current through the input module may become lower than the OFF
current.
Resistor
For the calculation example of a resistor to be connected, refer to the following.
■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
11 TROUBLESHOOTING
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11.5 Examples of Troubles with the I/O Module
DC input (sink)
Input
module
DC input (sink)
Input
module
Input module
24VDC
I =1.5mA
Z
Input impedance
R
3.0kΩ
1.5
× 3.0 = 3.0[kΩ]
1.5