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TABLE OF CONTENTS
General Safety Precautions & Installation Recommendations
HI520
safety precautions and installation recommendations apply. Procedures and instructions detailed in
this section may require special precautions to ensure the safety of the personnel performing the operations.
• Electrical connection, installation, start‑up, operation, and maintenance must be carried out by
specialized personnel only.
• The specialized personnel must have read and understood the instructions in this manual and should
adhere to them.
• User serviceable connections are all accessible inside the enclosure.
• Do not operate or energize the instrument with the case open.
• Before powering the controller, verify wiring has been done properly.
• Always disconnect the instrument from power when making electrical connections.
• Do not run other cables through the same cable gland with the power cable.
• A clearly marked disconnect switch must be installed in the vicinity of the instrument to ensure that
the electrical circuit is completely de‑energized for service or maintenance.
TABLE OF CONTENTS
1. Introduction ...........................................................................................................................................................4
2. Modbus Protocol Basics ...........................................................................................................................................4
3. Wiring & Controller Settings Configuration .................................................................................................................9
4.1. Modbus General Steps .............................................................................................................................. 12
4.2. Modbus Special Holding Registers ............................................................................................................. 13
4.3. Retrieving Controller Parameters ................................................................................................................ 14
4.4. Editing & Saving Controller Parameters ...................................................................................................... 14
5.1. Function Codes ........................................................................................................................................ 15
5.2. Exception Codes ....................................................................................................................................... 15
5.3. Coil Registers (0xxxx Addresses) ................................................................................................................. 16
5.4. Discrete Inputs (1xxxx Addresses) ............................................................................................................... 17
5.5. Input Registers (3xxxx Addresses) .............................................................................................................. 18
5.6. Holding Registers (4xxxx Addresses) ........................................................................................................... 32
