4.2 WLTS MODBUS Support Functions

0x03 – Read Holding Register

• Request Package (Example):
  • Device Address: 01
  • Function: 03
  • Register Start Address (Hi byte): 00
  • Register Start Address (Lo byte): 01
  • Number of Registers (Hi byte): 00
  • Number of Registers (Lo byte): 02
  • CRC: 95CB
• Response Package (Example):
  • Device Address: 01
  • Function: 03
  • Byte Count: 04
  • 1st Register data (Hi byte): 12
  • 1st Register data (Lo byte): 34
  • 2nd Register data (Hi byte): 56
  • 2nd Register data (Lo byte): 78
  • CRC: 8107

0x04 – Read Input Register

• Request Package (Example):
  • Device Address: 01
  • Function: 04
  • Register Start Address (Hi byte): 00
  • Register Start Address (Lo byte): 00
  • Number of Registers (Hi byte): 00
  • Number of Registers (Lo byte): 03
  • CRC: B00B
• Response Package (Example):
  • Device Address: 01
  • Function: 04
  • Byte Count: 06
  • 1st Register data (Hi byte): 12
  • 1st Register data (Lo byte): 34
  • 2nd Register data (Hi byte): 56
  • 2nd Register data (Lo byte): 78
  • 3rd Register data (Hi byte): 9A
  • 3rd Register data (Lo byte): BC
  • CRC: 28A5

0x06 – Pre-set Single Holding Register Value

• Request Package (Example):
  • Device Address: 01
  • Function: 06
  • Register Address (Hi byte): 00
  • Register Address (Lo byte): 02
  • Pre-set Value (Hi byte): 1A
  • Pre-set Value (Lo byte): 2B
  • CRC: 6375
• Response Package (Example):
  • Device Address: 01
  • Function: 06
  • Register Address (Hi byte): 00
  • Register Address (Lo byte): 02
  • Pre-set Value (Hi byte): 1A
  • Pre-set Value (Lo byte): 2B
  • CRC: 6375

0x10 – Pre-set Multi Holding Register Values

• Request Package (Example):
  • Device Address: 01
  • Function: 10
  • Start Register Address (Hi byte): 00
  • Start Register Address (Lo byte): 00
  • Number of Registers to set (Hi byte): 00
  • Number of Registers to set (Lo byte): 02
  • Byte Count 04
  • Pre-set 1st Register Value (Hi byte): 12
  • Pre-set 1st Register Value (Lo byte): 34
  • Pre-set 2nd Register Value (Hi byte): 56
  • Pre-set 2nd Register Value (Lo byte): 78
  • CRC: 889B
• Response Package (Example):
  • Device Address: 01
  • Function: 10
  • Start Register Address (Hi byte): 00
  • Start Register Address (Lo byte): 00
  • Number of Registers to set (Hi byte): 00
  • Number of Registers to set (Lo byte): 02
  • CRC: 41C8