Process Controls
PROPORTIONAL PLUS RATE CONTROL SYSTEMS
Figure 29
Effect of Disturbance on Proportional Plus Rate Reverse Acting
Controller
Applications
Proportional plus rate control is normally used with large capacity or slow-responding processes
such as temperature control. The leading action of the controller output compensates for the
lagging characteristics of large capacity, slow processes.
Rate action is not usually employed with fast responding processes such as flow control or noisy
processes because derivative action responds to any rate of change in the error signal, including
the noise.
Proportional plus rate controllers are useful with processes which are frequently started up and
shut down because it is not susceptible to reset windup.
Rev. 0
Page 41
IC-07
