Communication \ with MODBUS RTU

• Protocol description
• Technical Data
• MODBUS Addresses for Processor Modules PM5xx
  • MODBUS Address Table
  • Peculiarities for accessing MODBUS Addresses
  • Areas protected from read/write Access by MODBUS Client
  • Comparison between AC500 and AC31/S90 MODBUS addresses
• MODBUS Addresses for Processor Modules PM56xx
  • MODBUS Address Table
  • Peculiarities for accessing MODBUS Addresses
  • Areas protect from read/write access by MODBUS client
• Local Data of the MODBUS Client
• MODBUS Telegrams
  • FCT 1 or 2: Read n bits
  • FCT 3 or 4: Read n words
  • FCT 3 or 4: Read n double words
  • FCT \ 5: Write 1 bit
  • FCT \ 6: Write 1 word
  • FCT 7: Fast reading the status \ byte of the CPU
  • FCT 15: Write n bits
  • FCT \ 16: Write n words
  • FCT \ 16: Write n double words
  • FCT 22: Mask write register
  • FCT 23: Read/Write n words
  • Exception response by server
• Processing Bits
  • MODBUS Client
  • MODBUS Server
• Function Block COM_MOD_MAST