Algodue ELETTRONICA UPM309 Manual Del Usuario página 48

INDEX • Modbus protocol
1. Description ....................................................................................................................49
1.1 LRC GENERATION.................................................................................................................................................................... 50
1.2 CRC GENERATION ................................................................................................................................................................... 51
2. Command structure ......................................................................................................54
2.1 MODBUS RTU/ASCII ................................................................................................................................................................ 54
2.2 MODBUS TCP ........................................................................................................................................................................... 56
2.3 FLOATING POINT AS PER IEEE STANDARD ............................................................................................................................ 58
3. Exception codes .............................................................................................................59
3.1 MODBUS RTU/ASCII ................................................................................................................................................................ 59
3.2 MODBUS TCP ........................................................................................................................................................................... 59
4. Register tables ..............................................................................................................61
4.1 READING REGISTERS (FUNCTION CODE $03 / $04) .............................................................................................................. 62
4.2 READING AND WRITING REGISTERS (FUNCTION CODE $03 / $04 / $10) ............................................................................. 72
4.3 CONSIDERATIONS ON THE FULL SCALE VALUE CALCULATION ........................................................................................... 87
5. Reading command examples ........................................................................................88
5.1 MODBUS RTU/ASCII ................................................................................................................................................................ 88
5.2 MODBUS TCP ........................................................................................................................................................................... 89
6. Writing command examples ..........................................................................................92
6.1 MODBUS RTU/ASCII ................................................................................................................................................................ 92
6.2 MODBUS TCP ........................................................................................................................................................................... 98