I2C to Modbus TCP gateway communication with PLC

Hi, We try to connect PLC (TM241) to ASD7828.
We have Modbus TCP to I2C gateway: NCD5500.
We can open the port (rel led ok), but we don’t get any data from ADS7828.

With ANYI2C everything works correctly.

Is somebody know exactly how to call I2C through Modbus?
Maybe someone has a program example with an I2C call routine?

Thank you for your help