Method for transmitting data between a control unit and a plurality of remote I/O units of an automated installation

摘要

A control unit sends a plurality of request messages to the I/O units. The I/O units send a plurality of response messages to the control unit. The request messages and response messages are sent using radio-frequency signals. The I/O units expect to receive a request message within defined first time intervals, and the control unit expects to receive at least one response message within defined second time intervals. The control unit and the I/O units maintain a selected transmission frequency for as long as the request messages and response messages are received within the defined time intervals. The control unit and the I/O units change the transmission frequencies according to a defined pattern if no expected message is received within the defined time intervals.