Modbus TCP Hex Decoder

Modbus TCP is widely used in industrial automation for PLC, RTU, and SCADA communications. Header-level decoding helps validate transaction flow, addressing, and register operations.

Decode Modbus TCP Data

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Raw Decode Output

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Decoded Fields

Payload Hex: N/A

Payload ASCII: N/A

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About Modbus TCP

Modbus TCP wraps Modbus PDUs in an MBAP header carrying transaction context and unit identifier. Decoding these fields quickly exposes function intent and data boundaries for control-system troubleshooting.

Modbus TCP is widely used in industrial automation for PLC, RTU, and SCADA communications. Header-level decoding helps validate transaction flow, addressing, and register operations.

Modbus TCP Header Structure

Transaction Identifier (2 bytes): client-assigned request/response correlation value.
Protocol Identifier (2 bytes): set to 0x0000 for Modbus.
Length (2 bytes): byte count of Unit ID plus PDU.
Unit Identifier (1 byte): target device address behind the bridge/server.
Function Code (1 byte) + Data: operation type and function-specific payload.

Why Decode Modbus TCP Packets

Decode Modbus TCP ADU fields from hex including MBAP header, unit ID, function code, and request/response data.