Abstract: A diagnostic device and diagnostic method for monitoring the operation of a control loop with a controlled system having a valve as an actuator, wherein in the case of a substantially stepped profile of a setpoint, a linear submodel is identified, which is subsequently used, with a substantially constant setpoint, in order to identify a nonlinear submodel, which is arranged upstream of the linear submodel in a Hammerstein model for the controlled system so as to facilitate a quantitative assessment of the friction behavior of a valve with a comparatively low level of computing complexity.

Abstract: A diagnostic device and method for monitoring operation of automation system control loops includes an evaluation device and a data memory storing sequences of actual-value data of the control loops. An absolute value maximum of a cross-correlation function, for an excitation resulting from changes in a setpoint setting of one control loop, is determined as a first quantitative measure for positive time lag of the sequence of actual-value data of another control loop, and a numeric parameter evaluating an interaction effect of the one control loop on the other is determined as a function of the first quantitative measure. Strength and direction of the interaction effect are displayed. The calculations are repeated for all pairs of monitored control loops and a matrix of the numeric parameters is displayed.

Abstract: A diagnostic device and method for monitoring the operation of a slave or ratio control loop in a meshed control structure of an automation system. The diagnostic device includes an evaluation device and a data memory for storing sequences of setpoint data and actual value data. The evaluation device determines a first dimension for the scatter of the actual-value data and a second dimension for the scatter of the setpoint data. A characteristic number (CPIVar, CPIKas) for evaluating control quality is determined and/or displayed as a function of the ratio of the first dimension to the second dimension to enable an operator to evaluate the control loop status, permitting automated control loop evaluation of a fluctuating setpoint.

Abstract: A diagnostic device and diagnostic method for monitoring the operation of a control loop with a controlled system having a valve as an actuator, wherein in the case of a substantially stepped profile of a setpoint, a linear submodel is identified, which is subsequently used, with a substantially constant setpoint, in order to identify a nonlinear submodel, which is arranged upstream of the linear submodel in a Hammerstein model for the controlled system so as to facilitate a quantitative assessment of the friction behavior of a valve with a comparatively low level of computing complexity.

Abstract: A diagnostic device and method for monitoring operation of automation system control loops includes an evaluation device and a data memory storing sequences of actual-value data of the control loops. An absolute value maximum of a cross-correlation function, for an excitation resulting from changes in a setpoint setting of one control loop, is determined as a first quantitative measure for positive time lag of the sequence of actual-value data of another control loop, and a numeric parameter evaluating an interaction effect of the one control loop on the other is determined as a function of the first quantitative measure. Strength and direction of the interaction effect are displayed. The calculations are repeated for all pairs of monitored control loops and a matrix of the numeric parameters is displayed.

Abstract: A diagnostic device and method for monitoring the operation of a slave or ratio control loop in a meshed control structure of an automation system. The diagnostic device includes an evaluation device and a data memory for storing sequences of setpoint data and actual value data. The evaluation device determines a first dimension for the scatter of the actual-value data and a second dimension for the scatter of the setpoint data. A characteristic number (CPIVar, CPIKas) for evaluating control quality is determined and/or displayed as a function of the ratio of the first dimension to the second dimension to enable an operator to evaluate the control loop status, permitting automated control loop evaluation of a fluctuating setpoint.