Method for operating a control system of an industrial process

1 . A method for operating a control system of an industrial process, the control system having at least one control loop comprising a sensor, a control device and an actuator, the actuator being connected to the sensor via the industrial process,

wherein

a predefined test signal is injected at an arbitrary point ( 51 , 52 ) of the control loop, and

the response of the control loop as a function of the test signal is monitored at a separation of at least one control-loop element ( 41 to 43 ).

2 . The method as claimed in claim 1 ,

wherein

a test signal of defined duration, polarity and signal shape is temporarily superimposed on the measured signal detected by the sensor ( 200 ), with an expected value of the change in measured signal being assigned to each test signal,

the superimposed signal is sent to the control device ( 300 )

after a definable time has elapsed, the change in measured signal that is actually detected is compared with the expected value of the change in measured signal, and

differences between the change in measured signal actually detected and the expected value of the change in measured signal are signaled as an alert.

3 . The method as claimed in claim 2 ,

wherein

the test signal is superimposed periodically on the measured signal.

4 . The method as claimed in claim 2 ,

wherein

the test signal is superimposed on the measured signal on the basis of a given event occurring.