TOHO ELECTRONICS TTM000 - Manual (Page 22)

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6.4 Composition of an RTU response message
(transmitted from this product to a high-level computer)
For codes a) through h), see "6.5 Description of RTU codes."
6.4.1 Response message for a read request message
a) Slave address 1BH
b) Function code 03H
d) Number of data items 04H Number of registers 2
g)
Data for the first register
(a low-level word)
High level 03H ③ When writing ①, ②, ③, and ④
H in the data, write them in the
order described on the left-hand
side. (① represents 1 byte.)
Low level 09H ④
Data for the first register + 1
(a high-level word)
High level 00H ①
Low level 00H ②
e) CRC-16
Low level B4H
High level 91H
6.4.2 Response message for a write/store request message
a) Slave address 03H
b) Function code 10H
c) Register address
High level 00H
First register address
Low level 00H
d) Number of registers
High level 00H
Fixed at 2
Low level 02H
e) CRC-16
Low level 2AH
High level 40H
6.4.3 Response message in the case of an error
a) Slave address 1BH
b) Function code 83H In the case of an error, the function
code for the request message + 80H is
entered.
h) Error code 02H
e) CRC-16
Low level 36H
High level E1H