Function Codes
3 articles tagged "Function Codes" on the Modbus Poll blog.
This collection brings together every Function Codes article published on the Modbus Poll blog. "How to Read Modbus Holding Registers (FC03): A Practical Walkthrough", "How to Write Modbus Registers: FC06, FC16, and Coils FC05/FC15", "Modbus Function Codes Explained: FC01–FC06, FC15, FC16 (2026 Reference)" — each one is a practical, hands-on guide written for engineers and system integrators who work with Modbus Poll in real industrial deployments. Whether you are choosing between protocols, troubleshooting a connection, or planning an integration, these articles cover the concepts, the trade-offs, and the step-by-step details you need.
How to Read Modbus Holding Registers (FC03): A Practical Walkthrough
How to read Modbus holding registers with function code 03. Slave ID, start address, quantity, the FC03 frame, 16-bit byte order, and 32-bit scaling explained.
Read articleHow to Write Modbus Registers: FC06, FC16, and Coils FC05/FC15
How to write Modbus registers and coils. FC06 write single register, FC16 write multiple, FC05/FC15 coils. Frame layout, exception codes, and safe write practice.
Read articleModbus Function Codes Explained: FC01–FC06, FC15, FC16 (2026 Reference)
Every standard Modbus function code explained: FC01 read coils, FC03 read holding registers, FC06 write single register, FC16 write multiple. Request/response frame layout, byte order, and when to use each code.
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