Flow Ctrl Tech Engineering

Modbus Packet Sniffing with Wireshark & USB-to-RS485 Converters

Diagnose elusive field communication bugs by sniffing live RS-485 frames using Wireshark and USB serial dongles: enabling serial dissectors, CRC debugging, and timing analysis.

  • A passive USB-to-RS485 adapter can be placed across lines A and B without disrupting running communications.
  • Wireshark natively decodes Modbus RTU function codes, register boundaries, and validates CRC-16 checksums.
  • Packet sniffing reveals whether a slave is failing to reply or if the master is generating illegal addresses.

Flow Ctrl Tech Engineering: Turnkey industrial automation, PLC programming, SCADA development, HMI, fieldbuses, and IIoT architectures. Contact our engineering center at [email protected] or phone +91 91110 91005.