• This gateway can read Modbus data from your Modbus TCP devices and publish it as LonWorks data.
• It can also write to the Modbus TCP devices.
• This gateway can also do the reverse, read LonWorks data and publish it as Modbus TCP data.
• It can also write to the LonWorks devices.

In summary, this gateway can act as:

• Master on the Modbus TCP 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 TCP network: You can use the gateway in this mode if you have a Modbus TCP master on the network which would be reading data from the gateway.
• Client/Master on the LonWorks network: Hence it is capable of reading data from the various LonWorks devices and writing data to them if required.
• Server/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.

• On a site you have several Variable frequency drives that can provide data output on Modbus TCP.
• The site has a PLC on LonWorks control the Variable frequency drives.
• Since the Variable frequency drives provide data output on Modbus TCP and the Building management system 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 TCP is Ethernet based Protocol, and LonWorks is a Serial protocol . You need something that will convert data from LonWorks device to Modbus TCP and vice versa.

ProtoConvert’s Modbus TCP to LonWorks converter will be an excellent solution for this requirement. The gateway reads data from the Variable frequency drives on Modbus TCP. It caches this data internally and then provides it on LonWorks when requested from the Building Management system.

• On the other site we have thermostats that can provide data output on LonWorks.
• The site has a SCADA on Modbus TCP that needs the temperature data from thermostat on LonWorks.
• Since the thermostat provide data output on LonWorks and the SCADA understands only Modbus TCP 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 TCP is an Ethernet based Protocol , and LonWorks is a serial protocol . You need something that will convert data from LonWorks device to Modbus TCP and vice versa.

ProtoConvert’s Modbus TCP 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.

Modbus TCP:

ModbusTCP covers the use of Modbus communication via an 'Intranet' or 'Internet' environment using the TCP/IP protocols. The most common use of the protocols at this time is for Ethernet attachment of PLC's, I/O modules, and Gateways to other simple field buses or I/O networks. 
There will always be this question why the connection-oriented TCP/IP protocol is used rather than the datagram-oriented UDP. The Primary reason is to keep control of an individual ‘communication’ by isolating it in a connection which can be identified, cancelled , and supervised without the need of specific action on the client and server applications. This gives the mechanism a tolerance to network performance changes, and also gives a scope to add security features such as firewalls and proxies. 
MODBUS/TCP/IP handles two different situations. A connection can be recognized too easily at the protocol level. A single connection can be used to carry out multiple independent communications. To add to it, TCP/IP allows a huge number of concurrent connections, so the user decides to re-use an old connection or reconnect to a frequently used connection.

The Modbus device can be connected using an Ethernet port on the gateway. We can make a query using any standard Modbus Scanner to extract the value from a Modbus device. All requests are sent via TCP/IP on registered port 502.

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.