The Heat Exchanger with Return Water Control module controls a heat exchanger that uses superheated hot water as its heating source. This module manages the output water temperature. If the leaving heating source water temperature drops below the limit setpoint, the control valve is modulated to control the leaving heating source water at its low limit. This module also incorporates tracking the overridden value of the actual output object (AO, PAO). The module resets the PIDs to default tuning parameters if the Reset PID Tuning input is not Normal.
This module provides a second output that incorporates lead compensation to control devices. This function attempts to remove some of the dynamics of the control loop. This process results in forward-looking predictions and speeds up controller responses. The effect is similar to adding derivative action to the controller. Lead compensation is incorporated into most zone temperature control processes where oversized or nonlinear valves might be applied. For more information on the Lead Compensator block, see Lead Compensator in the Control category of the Logic section.
You can view and modify the modules in this group’s logic.