19
Chapter 4. Communication
z
End codes
End code Description Condition Operation
00 (Normal) Normal end*
• The transmitted message was normal. The value that was read is
returned.
99 (Error) Undefined
command
• The first two characters in the application layer
were an undefined command.
Only the end code is returned (no
data is appended).
40 (Error) Error in the
number of data
words
• A character other than 0H to FH was used for
the number of data words.
• The number of data words was less than 0.
• The number of data words was greater than the
number of accessible data words.
Only the end code is returned (no
data is appended).
41 (Error) Data address error
• A character other than 0H–FH was included in
the data address.
• The start data address was not specified.
• The data address was 255 or lower.
Only the end code is returned (no
data is appended).
* If the start address was normal but a later address causes a data address error, “0” is returned as the data from the abnormal
address.
z
Maximum number of data words read per message
16
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