Watts LF007 Serie Instrucciones De Instalación página 14

Function 02 – Read Input Status
Read the ON/OFF status of discrete digital input bits in the slave device. A typical function 02
command and response follow.
Command Usage
Address
Function
Addr HI
Addr LO
Data HI
Data LO
Response Message
Address
Function
Register Number
Data HI
Data LO
Data HI
Data LO
Error Check
Function 03 – Read Holding Registers
Returns the contents of hold registers (4X references) in the slave device. A typical function 03
command and response follow.
Command Usage
Address
Function
Addr HI
Addr LO
Data HI
Data LO
Response Message
Address
Function
Register Number
Data HI
Data LO
Error Check
One Byte Slave Address
One Byte Function Number
Starting Address HI Byte
Starting Address LO Byte
Typically ZERO
Number of bits, limited to 1..64
One Byte Slave Address
One Byte Function Number
Number of data bytes
Data Coils (27-20)
Data Coils (35-28)
Data Coils (43-36)
Data Coils (51-44)
Two Byte CRC
One Byte Slave Address
One Byte Function Number
Starting Register Address HI Byte
Starting Register Address LO Byte
Typically ZERO
Number of registers
One Byte Slave Address
One Byte Function Number
Number of data bytes
HI Byte (8-bits)
LO Byte (8-bits)
Two Byte CRC
Returns four bytes typically.
Returns four bytes typically.
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