The Lower Lachute Pond Control Modification project consisted of rescaling Head Pond and Trashrack levels to account for 1/100th of a foot measurement. The previous program allowed for only 1/10th of a foot measurement, which was found to be too gross to control the pond level adequately at this site.
ECI’s solution was to reprogram the PLC to provide the extra significant digit, test the result in the ECI Cumberland Lab 90-30 PLC before implementing, and then implement on the Lower La Chute PLC remotely.
The effectiveness of the program was tested by monitoring the pond level, making step changes to the pond level setpoint, and observing the wicket gate position and pond level on a graph.
The result was the pond control PID is now critically damped and working within the customer’s parameters. ABB S+ HMI was modified to show two places beyond the decimal point and checked to see that all setpoints were working correctly.