PROCESS CONTROL APPARATUS

• Main Author: HIROI, KAZUO
• Format: Patent
• Language: English; Korean
• Published: 22.03.1997
• Edition: 6
• Subjects: CONTROL OR REGULATING SYSTEMS IN GENERAL; CONTROLLING; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS ORELEMENTS; PHYSICS; REGULATING

요약없음 A set point value SV(s) and a process value PV(s) are supplied to a deviation arithmetic operation circuit (12), and thereby a deviation E(s) is obtained. The deviation E(s) is input to a control arithmetic operation circuit (14), and at least a PI control arithmetic operation is executed to obtain a manipulative value MV(s) such that the deviation E(s) is set at zero. An disturbance D(s) is added to the manipulative value MV(s) and the result of addition is supplied to object (20) to be controlled. A process value filter (28) having a lead/lag time proportional to an integral time TI of the PI control arithmetic operation is inserted in a feedback line of the process value PV(s) to the deviation arithmetic operation circuit (22). The transfer function of the filter (28) is (1 + alpha . beta .TI.s)/(1 + beta .TI.s). Although the optimal values of coefficients alpha and beta are 2.5 and 0.54, these values are variable in the range of 2 to 4 and the range of 0 to 1, respectively, depending on a first-order delay time T and a dead time L of the object (30). By setting alpha and beta in this way, the gain of the filter (28) can be set at 1 at steady state and more than 1 at transition state, so that both set point value following characteristic and disturbance suppression characteristic are improved.