The ModbusSlaveDevice represents a “virtual” Modbus device to serve data to a Modbus master over a serial connection, where station data appears as Modbus data items. It has 4 frozen “range” containers (ModbusRegisterRangeTables), which specify what Modbus addresses are available as coils, inputs, holding registers, and input registers.

Its Points extension (ModbusServerPointDeviceExt) contains Modbus proxy points with server proxy extensions (ModbusServerBooleanProxyExt, ModbusServerNumericProxyExt, ModbusServerRegisterBitProxyExt), used to read and write data to the defined data items. The device can also contain one or more ModbusServerStringRecord components.

For more details, see About Modbus server devices.