According to some embodiments of the present invention there is provided a computerized method for automatic monitoring of control systems. The method may comprise receiving electronic measurement values, measured on one or more conductors of computerized control devices, where the conductors may be a system bus conductor and/or and input-output line of a programmable logic controller. The method may comprise automatically calculating normal data patterns based on an analysis of the electronic measurement values. The method may comprise matching between new electronic measurement values measured on the computerized control devices and the normal data patterns to automatically detect abnormal data patterns. The method may comprise sending automatically an abnormal operation alert in response to the abnormal data patterns.