How to Set Up Cascade Control | Video

This video will show you how to set up the cascade control on the Pro-EC44 unit.

Transcript

Hi, I’m Ian Collins, product manager at West Control Solutions.

Cascade control is needed when it is difficult to achieve stable control within a system.

This can be caused when there is lag in the system leading to overshoot.

Where there is a high level of fluctuation in response to changes.

Or, when the process variables have a high risk of disturbance, for example, a flow of steam which doesn’t remain constant.

Cascade control, is a linking of two control loops in sequence, for a single application.

The first controller, is known as the master, it monitors the temperature of the end product. The output of the master controller is then used to drive the setpoint of the second control loop, known as the slave.

The slave controls the heater loop based on the sensor input of the heater and the setpoint driven by demand of the master.

As a result, the control system monitors changes at both the end product and at the heater, it controls the system accordingly.

A process requires to heat chocolate until melted for food manufacturing directly heating the chocolate creates a risk of scorching the end product due to very high temperatures generated by the heater.

Water is used as a medium, to heat the chocolate to the required temperature, the water temperature is fixed to never exceed 50oC. This ensures the chocolate is protected from high direct heat by introduces thermal lag to the system as temperature is conducted through the water to the chocolate.

This lag makes temperature over shoot and in stable control more likely, as a result cascade can be used to improve control performance.

Master controller measures the chocolate temperature and feeds the setpoint to the slave which monitors and heats the water as required. If temperature of the chocolate is rising too fast, the setpoint is reduced to the slave the controller can then vary the heat applied accordingly also based on the water temperature.

Controlled performance is improved due to faster responsiveness as a result over shoot is minimized and less fluctuation in control, there is less risk of damage to the end product and as a result leading to less waste and a more efficient system.

For more information, visit our website on www.west-cs.com