By Doug Cooper and Allen Houtz1 As discussed in previous articles, the purpose of the feed forward controller of the feed forward with feedback trim architecture is to reduce the impact of one specific disturbance, D, on our primary process variable, PV. An additional sensor must be located upstream in our process so we have […]
By Doug Cooper and Allen Houtz1 Both “feed forward with feedback trim” and cascade control can provide improved disturbance rejection performance. They have different architectures, however, andchoosing between the two depends on our specific control objective and the ability to obtain certain process measurements.
By Doug Cooper and Allen Houtz1 The most popular architectures for improved disturbance rejection performance arecascade control and the “feed forward with feedback trim” architecture introduced below. Like cascade, feed forward requires that additional instrumentation be purchased, installed and maintained. Both architectures also require additional engineering time for strategy design, implementation and tuning.