Omron CQM1H series Operation Manual page 237

Commands and Responses
Section 7-3
If the wrong command code or parameter is set to the output word, one of the
following error codes will be set to the input word.
E000: This error code will be set to the input word if a nonexisting command code
is used.
E003: This error code will be set to the input word if the mode designation for this
command is not correct.
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