TOHO ELECTRONICS TTX-700 - Manual (Page 34)

7. Specifications
7.1 Communications standard category: Compliant with EIA standard RS-485
7.2 Communications specifications
7.2.1 Communications system
Network: ................................... For RS-485, multi-drop system (up to 1 pair, 31 stations)
Direction of information: .......... Half duplex
Synchronization system: ........... Asynchronous
Transmission code: ................... ASCII, 7/8 bit code, except for BBC data
(highest-level bit = 0 in 8-bit code)
7.2.2 Interface system
Signal line: ................................ 2 lines for transmission and reception
Communications speed:............ One speed is selected from 1,200, 4,800, 9,600, and 19,200 bps
and this product is set to it.
Communications distance:........ 500m maximum
Provided that it varies somewhat depending on the cable and other
ambient conditions.
7.2.3 TOHO communications characters
Start bit length: ......................... Fixed at 1 bit
Stop bit length:.......................... Either 1 or 2 bit is selected and this product is set to it.
Data length:............................... Either 7 or 8 bit is selected and this product is set to it.
Parity: ....................................... No. Either odd or even is selected and this product is set to it.
BCC check:............................... Yes or no is selected and this product is set to it.
Communications address: ......... 1-99
7.2.4 MODBUS communications (RTU) characters
Start bit length: ......................... Fixed at 1 bit
Stop bit length:.......................... Either 1 or 2 bit is selected and this product is set to it. (If
parity-equipped, fixed at 1 bit.)
Data length:............................... Fixed at 8 bit.
Parity: ....................................... No. Either odd or even is selected and this product is set to it.
CRC-16 check: ......................... Fixed at yes.
Communications address: ......... 1-247
7.2.5 MODBUS communications (ASCII) characters
Start bit length: ......................... Fixed at 1 bit
Stop bit length:.......................... Either 1 or 2 bit is selected and this product is set to it. (If
parity-equipped, fixed at 1 bit.)
Data length:............................... Fixed at 7 bit.
Parity: ....................................... No. Either odd or even is selected and this product is set to it.
LRC check: ............................... Fixed at yes.
Communications address: ......... 1-247
7.2.6 MODBUS communications (ASCII/RTU) function codes
03H (reading the contents of the holding register)
10H (writing the contents of two or more holding registers)
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