Mitsubishi L Series User Manual page 167

(4) When digital output value cannot be read
Check item
Is there any problem with wiring, such as off or disconnection of
analog signal lines?
Is the CPU module in the STOP status?
Is the offset/gain setting correct?
Is input range setting correct?
Of the channels to input the analog value, is there any channel,
whose A/D conversion enable/disable setting (Un\G0) set to the A/D
conversion disable?
Is Operating condition setting request (Y9) performed?
Are the (V+) and (I+) terminals connected if the input source is
current?
Are the setting values correct when the average processing is
specified?
Is there any potential difference between the AG terminal and the
external device GND?
If digital output value cannot be read even after taking the above actions, the A/D converter module may be failed.
Please consult a local Mitsubishi representative.
(5) When an A/D conversion completed flag does not turn on in the normal mode
Check item
Isn't there any input signal error?
Action
Check the faulty area by checking signal line visually or
conductively.
Change the status of the CPU module to RUN.
Check if the offset/gain setting is correct.
When the user range setting is selected, change the input range to
the factory default setting. Then check if the A/D conversion
executes.
If the A/D conversion is properly executed, configure the offset/gain
setting again.
Check Setting range (Un\G20). When the setting range is wrong,
perform the intelligent function module switch setting again.
Check A/D conversion enable/disable setting (Un\G0). Then, set the
A/D conversion enable for Un\G0 with the program or the parameter
of the intelligent function module.
Check if the digital output value is stored in the CH
value (Un\G11 to Un\G14) after turning Operating condition setting
request (Y9) from OFF to ON, then to OFF.
When the problem has been solved, check the program again.
Make sure to connect the (V+) and (I+) terminals while inputting
current as shown in the external wiring.
When selecting the time average processing, set the values satisfy
the following condition.
• Setting value ≥ "4 (times) × conversion speed × Number of used
channels"
If the condition above is not met, digital output values remain 0.
Connect the AG terminal and the external device GND
Action
Check Input signal error detection flag (Un\G49)
CHAPTER 11 TROUBLESHOOTING
Digital output
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