Patent ID: 8160779

Claim:
Method for monitoring a control program of a control system with a control device ( 10 ) with a processor and a control program which from at least one measured value signal ( 281 ) fed into the control device ( 10 ) calculates at least one set value signal ( 282 ) and outputs the value signal ( 282 ) to a setting actuator ( 100 , 127 ), wherein at least at two predefined flow-gate points in the control program a check point (K) is defined at which the control device ( 10 ) outputs a program output value ( 283 , 284 ), which forms a monitoring signal ( 284 ) and outputs the monitoring signal ( 284 ) to a monitoring device ( 12 ), characterized in that the check point (K) initiates output of a monitoring signal ( 284 ) which contains at least two signal elements ( 284 a, b, c ) of three possible signal elements, wherein a first signal element ( 284 a ) represents a first check point (K 1 ) through which the control program is to have passed immediately before a current check point (K 2 ), and a second signal element ( 284 b ) representing the current check point, and a third signal element ( 284 c ) which represents a third check point (K 3 ) intended next in the program consecution, wherein the monitoring device ( 12 ) tests the monitoring signal ( 284 ) for the correct state of the monitoring signal ( 284 ) in that the third signal element ( 284 c ) is stored in a first store ( 15 ) and a signal ( 284 c ′) read from the first store ( 15 ) is compared in a first comparator ( 17 ) with a current actual value signal ( 284 b ) of the current check point (K 2 ) and simultaneously a second signal element ( 284 b ) is stored in a second store ( 16 ) and a signal ( 284 b ′) read from the second store ( 16 ) is compared in a second comparator ( 18 ) with the first signal element ( 284 a ) of the first check point (K 1 ) and that the two output signals of the comparators ( 17 , 18 ) are linked with an OR-gate element which generates a state signal and, in the event of an error function of the program consecution, outputs an error signal ( 285 ).