Troubleshooting for Each Phenomenon
This section describes troubleshooting for each phenomenon.
Perform troubleshooting for each phenomenon when the I/O module does not operate properly with no error. If an error
occurs in the I/O module, identify the cause of the error using the engineering tool.
Check the following items in the order from the top.
When the ON/OFF status of an external input cannot be read
Is the corresponding I/O LED of the input module
or I/O combined module on when an external
input device is on?
Is the setting of the refresh device correct?
Is Remote READY (RWr0.b11) on?
Is the input OFF delay function used correctly?
Is any bit of Input X port status (RWr4) on?
11.5 Troubleshooting for Each Phenomenon
If the LED does not turn on, there is a problem on the input wiring.
Check the wiring confirming that the input wiring is not disconnected or short-circuited, or the voltage of the
input signal is correct.
For the rated input voltage, check the rated input voltage in the specifications of each input module or I/O
Page 20 Input module
Page 34 I/O combined module
Refer to the following as well.
Page 134 Troubleshooting for input circuit
Check the refresh parameter and correct the setting of the refresh device so that it matches with the setting
in the program. For the setting of the refresh parameters, refer to the following.
User's manual for the master/local module used
To enable reading the ON/OFF status of the external input when the module power supply is on, the initial
processing must be executed by using Initial processing request flag (RWr0.b8) and Initial processing
completion flag (RWw0.b8). Execute the initial processing to check that Remote READY (RWr0.b11) is on.
For details, refer to the following.
Page 144 Initial processing request flag (RWr0.b8)
Page 152 Initial processing completion flag (RWw0.b8)
When the input OFF delay function is enabled, Remote input signal (RX) turns off after the delay time
passes following OFF of an external device. Disable the input OFF delay function or change the setting of
the delay time.
For details on the setting related to the input OFF delay function, refer to the following.
Page 84 Input OFF Delay Function
Page 156 Input OFF delay setting
When any bit of Input X port status (RWr4) is on, a short circuit was detected in the input port for the bit.
Check the wiring after checking that the input wiring is not disconnected or short-circuited and the voltage
of the input signal is correct.