The industrial- and building automation market contains a wide range of applications that are designed for serial communication using the ModBus RTU protocol. Target applications for this gateway are products acting as a MASTER on the Modbus side: PLC's, drives, controllers, text displays, HMI's e.t.c. This gateway has the functionality of a SLAVE on the Modbus RTU side.

The Gateway makes communication possible between LonWorks network and devices using the Modbus protocol. The Gateway converts data going between the LonWorks network and the Modbus network so devices in different networks can understand each other's application data.

After the LonWorks installation (binding LonWorks variables between the motor and the gateway), the variables like nviDrvSpeedStpt (SNVT_switch) can be read and converted into the Modbus register in the gateway. All mapping between the variables and the Modbus registers are made with the configuration tool, LWtool.

The configuration tool handles the mapping between LonWorks variables and the Modbus registers. The variables will be added to the registers in the order of configuration. When all variables are configured, you will get a configuration file. This file you will download to the Gateway with a "download program" attached to the PC. The application uses a serial configuration cable between the PC and the Gateway.

When adding a LonWorks in-variable which is 2 byte long, the data in the variable will be placed in the Modbus IN register 30001-30001. Next added in-variable which could be 3 byte will be added to register IN 30002-30003, it takes the space of two 16bit registers even if it only is 3 byte long. Same procedure for the out-variables which will be mapped into the holding register with start from address 40001 in the register.

LWtool have the possibility to export

• XIF file (for installation tools)
• Configuration file (to download into the gateway)
• Node documentation (a HTML document with register information)