7bit Mediator

Custom protocol serial to Modbus TCP gateway

7bit Mediator is an Ethernet-to-serial gateway for an arbitrary user device protocol. Its main purpose is to speed up communication and facilitate access to controllers that use the non-standard and slow RS-485 fieldbus interface and connect them using the standard Modbus TCP protocol. Exchange via RS-485 is implemented using the popular Lua scripting language. It has one PoE port (power supply from 9 – 48Vdc) for connecting to the network, WiFi – client mode, one isolated RS-485 port.

Apllication fields

Connection to the monitoring or automation system of non-standard slow devices for which adding or developing an end device driver is impractical or impossible. Thus, such a device can be simply connected to the system using flexible communication cables Ethernet and Wi-Fi capabilities. Examples of such end devices can be:

  • power meters, heat meters
  • scales, bar code readers
  • RFID and & other identification systems

How it works?

With the help of Mediator, you can connect a remote serial device with a COM port (electrical, heat meters, scales, etc.) to the monitoring or automation system via Ethernet and implement communication with it according to a non-standard protocol, using a processor written in the language Lua. A web browser is sufficient to configure the gateway. Mediator works asynchronously, reading the necessary data into the internal memory accessible to clients via Modbus TCP.

When to use

  1. Integration of non-standard devices into PLC-based systems, for example, is very difficult due to low-level development and debugging tools. At the same time, manufacturers of such equipment provide examples of working with the device in high-level programming languages such as C++, Python, and Visual Basic. The Lua programming language is similar to these high-level programming languages, and has a convenient debugging console. Separating the task of communicating with an atypically complex protocol, such as DLMS for electric meters, from the main control application makes the integration process much easier, faster and more reliable.
  2. Processing of terminal devices. A terminal device is a device that sends data to the port asynchronously from the control system – by event, or simply constantly sends a stream of data. It is impossible to connect such a device to an existing network of subordinate devices, such as Modbus RTU devices.
  3. Additional logic that must be executed directly at the time of reading. For example, there is a device that provides data much faster than the scan time of an existing RS-485 network. In order not to miss important data from this device, Mediator can remember the data for the required time of the control system.

More advantages

  • The built-in Wi-Fi interface allows you to connect to the data collection system in the device where there is no way to lay communications.
  • Since, from a functional point of view, the gateway must be located somewhere “in the field”, for ease of integration, it is powered by the same cable as the Ethernet network (universal power supply with a voltage of 9-48 V or PoE)
  • The standard compact form factor of the distribution circuit breaker is attached directly to the DIN profile in the cabinet.
  • Convenient configuration of the module using the built-in web page

Technical specifications

Supply 9 – 48 Vdc, 1W max.
Modbus TCP 1 x Fast Ethernet, 1 WiFi (client mode, master for setup)
RS-485 Швидкість 300 .. 115200, гальванична ізоляція 2500 Vdc
Operating conditions 0°C – 55°C, 5 – 90% (w/o condending)
Storage condtitions -25°C – 70°C, 5 – 95% (w/o condending)
Protection / Weight IP40, 80 g.

 

Dimensions