PCT51 is a visible and easy to understand water flow control process.
Water stored in the sump tank is pumped through a parallel pipe
arrangement mounted on the lid of the tank and returns to the tank via
two outlets, a software switched divert valve prior to the flow-meter and
a manually operated variable valve after the flow-meter. Both outlets
also incorporate interchangeable orifices to vary their characteristics.
Repeatable disturbances can be implemented using the solenoid
valve and a wide range of different control investigations can be
implemented using the interchangeable orifices and adjustable valves.
The PCT51 is an ideal system for demonstrating the onset of instability,
the importance of filtering on the sensor output, and the trade-off
between filter weighting and proportional gain on stability.