ModbusBB
Modbus TCP/RTU/ASCII master & slave simulator for Windows, GUI+CLI
ModbusBB is a Windows Modbus master/client, slave/server simulator and command-line tool for SCADA and automation engineers testing PLCs, meters, inverters, drives and gateways.
Connect to multiple devices over TCP, RTU, ASCII, RTU-over-TCP or UDP. 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.