Lumel RE15, User Manual, Page: 16 / 28

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The data field:
In a correct answer the slave device can return data to the data field
(certain information required by the master unit). In the
incorrect answer the slave unit returns the error code to the data
field. It defines conditions of the slave device which had produced
the error.
An example considering a demand of a master device: read out 4520
register (11A8h) and the answer of the slave unit: forbidden data
address, because the maximal register address in the RE15 con-
troller is 4519.
Data are in the hexadecimal shape.
Example: demand
Slave Function Variable Variable Number of Number of Checksum
address address address variables variables
Hi Lo Hi Lo
0A 03 12 BO 00 01 39 LRC
Example: answer
Address Function Error Checksum
0A 83 02 71 LRC
Possible error codes and their meanings are shown in the table
below.
Code Meaning
01 Forbidden function
02 Forbidden data address
03 Forbidden data value