Modbus-rtu (over rs-485), Wiring pinout, Modbus setup – Hardy HI 6300 Series User Manual
Page 41: Modbus functions, Modbus registers, Modbus setup modbus functions modbus registers
Network Configuration 33
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Modbus-RTU (over RS-485)
Step 1. Setup a slave address assigned to the HI 6300 series instrument from the
communications menu and the Modbus-RTU submenu.. Use a unique address
between 1 and 247
Step 2. Set the Baud Rate to the same as the master device, typically 9600 or 19,200
Step 3. Set the Parity Bit parameter to match that of the Modbus-RTU master (EVEN,
ODD, or OFF).
Step 4. Set the Termination to match the physical wiring of the serial port (ENABLE,
DISABLE, or LINK).
Wiring Pinout
The RS-485 serial port pinout is:
Modbus Setup
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Slave Address may be set to any number in the range of 1-247.
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Set Baud Rate parameter to match the settings of the Modbus master
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Set Parity to match the settings of the Modbus master
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Set Termination to Enable, Disable or Link to match the physical wiring.
NOTE
For a full list of I/O Communications parameters, see Appendix A.
Modbus Functions
The Modbus functions allowed in the HI 6300 are:
Function 3: Modbus Read Holding Registers
Function 4: Modbus Read Input Registers
Function 6: Modbus Write Single Register
Function 16 (0x10): Modbus Write Multiple Registers.
Modbus Registers
This instrument has 64 16-bit MODBUS input registers and 64 16-bit output registers. The
data in these registers is in "big endian" format, meaning that the most significant byte
comes first.
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The first 6 registers (0 – 5) are used for the “command interface” in the unit.
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Registers 6 & 7 will contain the Net weight in 32 bit floating point format.