This is often the main reason users search for "Modbus Poll key new." Users download the software, but after 30 days (or in some trial modes, 10 minutes), they need a key to keep using it.
Elias opened Modbus Poll and clicked Connection -> New . He created a custom profile: ID 247 (unused, reserved for test). He mapped 50 registers, but not the standard ones. He mapped exception codes — the Modbus shadow space. When a master polls a slave for a nonexistent register, the slave returns an exception. Most systems ignore exceptions. Elias didn’t. modbus poll key new