Modbus+poll+key+__link__ Full Direct

The "Key Full" mechanism ensures that the master device retrieves complete and accurate data from the slave device. When a slave device responds with a data packet, it includes a specific key or identifier that indicates the data packet's validity. The master device checks this key to ensure that the data packet has not been corrupted during transmission. If the key is valid, the master device accepts the data packet; otherwise, it requests the data packet again.