D-24
6 Troubleshooting
6.5 Program Check
FX
3S
/FX
3G
/FX
3GC
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
FX3G-2AD-BD (2-channel Analog Input)
4. Error status
Check that no error is detected in the 2AD-BD.
If an error is detected, check the details of the error, and then check the wiring and programs.
→ For a detailed description of special devices, refer to Chapter 4.
6.5 Program Check
Check the following items for the program:
1. Clearing of error status at power on
When the power is turned off and then on again, the error status should be cleared (b6 and b7 should turn off)
using the program.
2. Check of storage devices
Verify that different values are not being stored in the same device by other parts of the program.
6.6 Error Status Check
If an error occurs in the 2AD-BD, the corresponding bit will turn on.
The bit which is turned ON due to the error status is held ON until overwritten to OFF by the program or the
power is cycled. If b6 or b7 is turned ON, then it is necessary to clear the error status using the program the
next time the power of the PLC is cycled.
*1. Only available for FX
3S PLC.
The under-scale detection function is valid only for current input mode.
To solve the problem, refer to the troubleshooting method described below:
1. Over-scale detection (b0, b1)
1) Description of error
The input analog value (voltage or current value) is outside the specified range.
Voltage input mode: The input voltage value is over the specified upper limit of 10.2 V.
Current input mode: The input current value is over the specified upper limit of 20.32 mA.
2) Remedy
Check that the input analog value is within the specified range. Also check the wiring.
2. EEPROM error (b4)
1) Description of error
The adjustment data which was set in the EEPROM before delivery from our factory cannot be read out
properly or has been destroyed.
2) Remedy
Please contact your local Mitsubishi Electric representative.
3. Averaging time setting error (b5)
1) Description of error
The averaging time set for one of the channels (channels 1 to 2) is outside the specified range: 1 to 4095.
2) Remedy
Check that the averaging time is set correctly for each channel.
Bit Description Bit Description
b0 Channel-1 over-scale detection b6 2AD-BD hardware error
b1 Channel-2 over-scale detection b7 2AD-BD communication data error
b2 Unused b8
Channel-1 under-scale detection
*1
b3 Unused b9
Channel-2 under-scale detection
*1
b4 EEPROM error b10 to b15 Unused
b5 Averaging time setting error - -
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