Modbus RTU to LonWorks Gateway | |Modbus RTU to LonWorks Protocol Converter
  • This gateway can read Modbus data from your Modbus RTU devices and publish it as LonWorks data.
  • It can also write to the Modbus RTU devices.
  • This gateway can also do the reverse, read Lonworks data and publish it as Modbus RTU data.
  • It can also write to the LonWoks devices.

In summary, this gateway can act as:

Master on the Modbus RTU network: Hence it is capable of reading data from the various Modbus slave devices and writing data to them if required.

Slave on the Modbus RTU network: You can use the gateway in this mode if you have a Modbus RTU master on the network which would be reading data from the gateway.

Master on the LonWorks network: Hence it is capable of reading data from the various LonWorks devices and writing data to them if required.

Slave on the LonWorks network: The gateway can be configured to be a server of data values, hence another LonWorks client can read data from the gateway and write data into the gateway.

Block Diagram:


Application Scenario 1
  • On a site you have several Schneider Ion energy meters that can provide data output on Modbus RTU.
  • The site has a LonWorks based Controller that needs the energy data from the Schneider ion meters.
  • Since the Schneider ion meters provide data output on Modbus RTU and the controller understands only LonWorks a direct data exchange is not possible.

Block Diagram:


Solution:

The devices can not directly communicate with each other as they are not on the same protocol. Modbus RTU and LonWorks are Serial Protocols. You need something that will convert data from LonWorks device to Modbus RTU and vice versa.

ProtoConvert’s Modbus RTU to LonWorks converter will be an excellent solution for this requirement. The gateway reads data from the Energy meters on Modbus RTU. It caches this data internally and then provides it on LonWorks when requested from the Controller. 

Applicaiton Scenario 2
  • On the other site we have thermostat that can provide data output on LonWorks.
  • The site has a PLC on Modbus RTU that needs the temperature data from thermostat on LonWorks.
  • Since the thermostat provides data output on LonWorks and the PLC understands only Modbus RTU and a direct data exchange is not possible.

Block Diagram:


Solution:

The devices can not directly communicate with each other as they are not on the same protocol. Modbus RTU and Lonworks are serial Protocols. You need something that will convert data from Lonworks device to Modbus RTU and vice versa.

ProtoConvert’s Modbus RTU to LonWorks converter will be an excellent solution for this requirement. The gateway reads data from the Thermostat on LonWorks. It caches this data internally and then provides it on Modbus RTU when requested from the PLC.

An Overview of the two protocols

Modbus RTU:

ModbusRTU is a serial communication protocol that connects different devices on the same network and would make the communication between them possible.

Modbus is transmitted over serial lines between devices. The cables used for the conecction are either RS-485 or RS-232 cables. The simplest setup would be a single serial cable connecting the serial ports on two devices, a Master and a Slave.

The data is sent as series of ones and zeroes called bits. Each bit is sent as a voltage. Zeroes are sent as positive voltages and ones as negative. The bits are sent very quickly. A typical transmission speed is 9600 baud (bits per second).

LonWorks:

LonWorks (local operation network) is a networking platform specifically created to address the needs of control applications. This platform is created for networking devices over media such as twisted pair, power lines, fibre optics, and RF. It is used for the automation of various functions within buildings such as lighting and HVAC see building automation.

There are two physical-layer signalling technologies, twisted pair "free topology" and power line carrier, are typically included in each of the standards created around the LonWorks technology. The two-wire layer operates at 78 kbit/s using differential Manchester encoding, while the power line achieves either 5.4 or 3.6 kbit/s, depending on frequency.

Additionally, the LonWorks platform uses an affiliated Internet protocol (IP) tunnelling standard in use by a number of manufacturers to connect the devices on previously deployed and new LonWorks platform-based networks to IP-aware applications or remote network-management tools. Many LonWorks platform-based control applications are being implemented with some sort of IP integration, either at the UI/application level or in the controls infrastructure.