The Modbus industrial protocol was developed in 1979 to make communication possible between automation devices. Originally implemented as an application-level protocol intended to transfer data over a serial layer, the protocol has expanded to include implementations over serial (RS232, RS485/RS422), TCP/IP, and the user datagram protocol (UDP). Today, it is a common protocol used by countless devices for simple, reliable, and efficient communication across a variety of modern networks.

Why use Haidar's ModBus Modules

Haidar's ModBus Modules are low cost yet very powerful modules that can be used for any application requires remote control and monitoring capability. Haidar's ModBus modules are designed with embedded control in mind. Most industrial process systems require user interface and control, 
simple microcontroller board can be used as a bridge between Haidar's user interface touch screens and Haidar's ModBus modules, forming robust and flexible control and monitoring architecture that can be used across wide range of industrial applications.
Below are the main features of Haidar's ModBus Modules:

  • Low Cost
  • Wide selection of modules
  • Serial RS422 (4-wire RS485) or Ethernet TCP/IP interface
  • Multiple mounting options
  • Multiple network options
  • Powerful 32-bit microcontroller on board
  • Single 24V DC power input
  • Pluggable screw terminals
  • Dual RJ45 plugs for RS422 network 
Network Configurations

Embedded Control and Monitoring
Brain or main controller board is used to bridge the user interface touch screen to the modbus modules.

                           Embedded GUI Controller

ModBus RTU Serial RS422 (4-wire RS485)
RMC-C800 network interface module is used to convert RS232 or USB to RS422 bus.

ModBus RTU Ethernet TCP/IP
In this configuration, all modules are set with ModBus TCP option. An Ethernet switch or router is used to communicate with each module via a network or the internet.


ModBus RTU Ethernet TCP/IP to Serial RS422
In this configuration, RMC-C810 network module is used to convert the master ModBus TCP to Serial RS422. This is the recommended configuration for Ethernet network.


ModBus Modules

Haidar offer complete stand-alone data acquisition modules which are broadly used in IoT or other industrial applications, such as facility monitoring, environment monitoring, and industrial process control. Haidar distributed remote monitor and control IO modules are categorized into two families, Ethernet IO (RMC-xxxx-E series) and Full-Duplex RS-485 IO (RMC-xxxx-S series), which are subdivided into Analog IO and Digital IO modules. All of them support Modbus RTU communication protocol. Available Modules:
  • RMC-D100-x: 8 Digital input & 8 Digital output
  • RMC-D110-x: 8 Digital input & 8 Relay output
  • RMC-D120-x: 16 Digital input
  • RMC-D130-x: 16 Digital output
  • RMC-D140-x: 16 Relay output
  • RMC-A200-x: 8 Analog input, 4 analog output and 4 4-20ma CLT
  • RMC-T300-x: 4 Thermocouple, 4 Relay output and 4 PWM output
  • RMC-C800: RS232/USB To RS422 interface module
  • RMC-C810: ModBus TCP To RS422 interface module