Mitsubishi Q01CPU

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12.5 I/O Module Troubleshooting
12.5.1 Input circuit troubleshooting
12
TROUBLESHOOTING
(From preceding page)
• In order to satisfy the condition that the OFF current of the QX40 is 1.7mA or
less, the resistance 'R', in which a 0.63mA or more current flows, shall be
connected.
Calculating with the formula "IR: IZ = Z (Input impedance): R",
the resistance 'R' will be R<15.11k .
Consequently, if the resistance 'R' is set to 12k , the electric power 'W' of the
resistance 'R' will be calculated in the following formula,
W= (Input voltage)
2
/R=28.8
2
/12000=0.069[W].
• Since the resistance requires the electric power which is 3 to 5 times of the power
actually consumed, the resistance to be connected to the corresponding terminal
shall be 12.0k and 1/4 to 1[W].
• The OFF voltage of the QX40 when the resistance 'R' calculated above is
connected will be 8.90[V]
This also satisfies the condition that the OFF voltage of the QX40 is 11V or less.
R< Z (Input impedance)= 5.6=15.11[k ]
IR
IZ
0.63
1.7
2.33[mA]=8.90[V]
1
1 1
+
12.0[k ]
5.6[k ]