MODBUS TCP - conversion data in WORD

I have a network analyzer with modbus TCP (voltage, current …). Analyzer data is in the form of Word. I need to display the actual U1 voltage value. Voltage U1 is written in register 4352(U1a) and in register 4353 (U1b). I need to convert word to int. On a PLC, I have a conversion designed in the ST programming language in shape
N1: = (SHL (WORD_TO_DWORD (U1a), 16) OR WORD_TO_DWORD (U1b))
N2: = ADR (N1)