Specifications

Appendix C - Glossary of Terms RS-422 And RS-485 Applications Ebook
Page 113 of 137 Manual Documentation Number: <DocNumber>
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Max Baud Rate
Maximum baud rate supported by the hardware (electronics circuitry)
Mbps
Mega bits per second. A data rate in million bits per second
Modbus
Modbus is a serial communications protocol published by Modicon in 1979 for
use with its programmable logic controllers (PLCs). It has become a de facto
standard communications protocol in industry, and is now the most commonly
available means of connecting industrial electronic devices. The main reasons
for the extensive use of Modbus over other communications protocols are:
1. It is openly published and royalty-free
2. Relatively easy industrial network to deploy
3. It moves raw bits or words without placing many restrictions on vendors
Modbus allows for communication between many devices connected to the
same network, for example a system that measures temperature and humidity
and communicates the results to a computer. Modbus is often used to connect
a supervisory computer with a remote terminal unit (RTU) in supervisory
control and data acquisition (SCADA) systems.
Modbus Gateway
Protocols are like languages, French, English, Spanish, or Japanese. If devices
are to understand each other, they must speak the same language, similar to
using a phone, otherwise a translator is needed. Interfaces such as RS232,
RS422, RS485, or Ethernet only define the electrical interface. ModBus has
several dialects, ASCII, RTU or Modbus/TCP. A Modbus Gateway like the Vlinx
MESR series bridges between ModBus protocols, enabling communications
between Modbus devices speaking different dialects. Protocol Gateways like
our Connect Pro can translate between more than 100 different protocols,
enabling a device using one protocol to access data in a different protocol and