ProtoLink 1.4.0
Questions
Short answers about launch, addresses, and device connections
What can ProtoLink do?
ProtoLink works with Modbus TCP and Modbus RTU, reads FC01–FC04, writes FC05/06/15/16, scans the local network, and displays actual TCP/RTU traffic.
Which register address should I enter?
ProtoLink uses the zero-based protocol data address. If the documentation lists holding register 40001, you normally select FC03 and enter register address 0.
Why do I get a timeout?
For TCP, check the IP address, port, network, and Unit ID. For RTU, check the serial port, baud rate, parity, stop bits, byte size, Unit ID, and physical RS‑485 connection.
Where is the serial port?
Windows uses a COM port, Linux uses /dev/ttyUSB* or /dev/ttyACM*, and macOS normally uses /dev/cu.*.
Do I need Python or Node.js?
No. Packaged ProtoLink builds contain the required components. Python, Node.js, and npm are only needed for development from source.
How do I verify launch?
Open 127.0.0.1:8000 or request /api/healthz. The response should contain status ok.
What does the traffic monitor show?
It displays TCP/RTU requests, responses, and errors: direction, endpoint, Unit ID, function code, attempt, duration, and the complete HEX frame. Events can be filtered and exported as JSONL.