21
Chapter 4.  Communication
z
End codes
End code Description Condition Operation
00 (Normal) Normal end
• The transmitted message was normal. All specified data was written.
99 (Error) Undefined 
command
• The first two characters in the application layer 
were an undefined command.
No data was written.
40 (Error) Error in the 
number of data 
words
• The number of data words was greater than the 
number of accessible data words.  
and  
No data could be written. (All data in the 
transmitted message met the conditions for an 
error or alarm.)
No data was written.
41 (Error) Data address error
• A character other than 0H–FH was used for the 
start data address.
• The start data address was not specified. 
• The start data address was 255 or lower. 
No data was written.
42 (Error) Data range error
• A character other than 0H–FH was included in 
the write data.
• Write data was out of the data range  
and  
No data could be written. (All data in the 
transmitted message met the conditions for an 
error or alarm.)
No data was written.
43 (Error) Could not write
• The process did not have write permission for a 
data address.  
and  
No data could be written. (All data in the 
transmitted message met the conditions for an 
error or alarm.)
No data was written.
20 (Warning) Data count 
warning
• The number of data words was greater than the 
number of accessible data words.
Data was written to the accessible 
data addresses.
21 (Warning) Data address error
• The data address was not specified (other than 
the start address).
Data was written to the accessible 
data addresses.
22 (Warning) Data range error
• A character other than 0H–FH was included in 
the write data.
• Write data was out of the data range
Valid data was written.
23 (Warning) Could not write
• The process did not have write permission for a 
data address.
No data was written to read-only 
data addresses. If there was data 
for accessible data addresses, it 
was written.
z
Maximum number of write data words per message
16