ModbusBB
Modbus TCP/RTU/ASCII master & slave simulator for Windows, GUI+CLI
...Read/write coils and registers, inspect raw TX/RX frames, decode 16/32/64-bit values and strings with selectable byte order, scaling and units, and use FC08/17/22/23/43 device tools.
Simulate devices with value generators, exceptions and delays. Scan devices/registers, plot trends, log CSV data, configure watchdog alerts and automate tests with CLI JSON/CSV output.
Free 30-day trial: all features, 15-minute sessions. $10 USD lifetime license: unlimited session time, one user on up to 3 computers, free updates. License activation and verification at least every 30 days require internet access.
Published by Max Energic Apps. ...