Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 1882

Operation error
Error code Description
(SD0)
3401H An ASCII code other than 30H to 39H, 20H, and 00H is input.
The STRING data type value input is out of the following range:
-2147483648 to 4147483647
25 TYPE CONVERSION FUNCTIONS
1880
25.60 Converting STRING to TIME