An open-source, Qt-based implementation of a Modbus master application. It includes a graphical user interface, supports both Modbus RTU and TCP, and allows you to monitor and write to registers without session time limits. 2. Modbus Pal
A standard single‑user license costs around €99 (excluding VAT). It never expires and includes one year of free updates and email support. After one year, the software continues working; updates require a reduced renewal fee. modbus poll registration key generator