When A Digital Output Value Cannot Be Read - Mitsubishi Electric Melsec iQ-R Series User Manual

When a digital output value cannot be read

Follow the steps in the table below to find the cause of the trouble.
Description
■Step 1: Checking the digital output value
Check the following.
• Check whether digital output values have
been stored in the buffer memory.
• Check whether the program for reading
digital output values has an error.
■Step 2: Checking the conversion status
Check the execution status of the A/D
conversion in the module, such as whether
the A/D converter module have executed
the A/D conversion.
4 TROUBLESHOOTING
76
4.3 Troubleshooting by Symptom
Procedure
When digital output values
cannot be read
Check the stored value in
'CH1 Digital output value' (Un\G400).
Are the stored
digital output values corresponding
to the analog input?
NO
Ò
Ò
Check the stored value in 'CH1 A/D conversion
enable/disable setting' (Un\G500).
Is "A/D conversion disable (1)" stored?
NO
Check 'External power supply READY flag'
(X7).
Is the signal turned off?
NO
Ó
Monitor the buffer memory area with the
*1
monitor function of the engineering tool.
The read program has an error or the
CPU module is in STOP status.
YES
Check item 1
Monitor the buffer memory area with the
*1
monitor function of the engineering tool.
A/D conversion is not enabled.
YES
Check item 2
Monitor the input signal with the monitor
*1
function of the engineering tool.
24VDC is not supplied to the external power
supply.
YES
Check item 3