TOHO ELECTRONICS TTX-700 User Manual
Page 3
6
MODBUS communications control ...................................................................................................... 20
6.1
Communications procedure........................................................................................................ 20
6.2
Message types ............................................................................................................................ 20
6.3
Composition of an RTU request message
(transmitted from a high-level computer to this product)........................................................... 21
6.4
Composition of an RTU response message
(transmitted from this product to a high-level computer)........................................................... 22
6.5
Description of RTU codes .......................................................................................................... 23
6.6
Precautions on RTU communications ........................................................................................ 25
6.7
Example of CRC-16 calculations ............................................................................................... 26
6.8
Composition of an ASCII request message
(transmitted from a high-level computer to this product)........................................................... 27
6.9
Composition of ASCII response messages
(transmitted from this product to a high-level computer)........................................................... 28
6.10 Description of ASCII codes........................................................................................................ 30
6.11 Precautions on ASCII communications...................................................................................... 32
6.12 Example of LRC calculations..................................................................................................... 33
7.
Specifications ........................................................................................................................................ 34
7.1
Communications standard category: Compliant with EIA standard RS-485 ............................. 34
7.2
Communications specifications.................................................................................................. 34
8.
Connections........................................................................................................................................... 35
8.1
Connections for the RS-485 ....................................................................................................... 35
9.
Table of ASCII codes ............................................................................................................................ 36
10. Table of identifiers (codes).................................................................................................................... 37
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