Lesson 3 - Principles of Process Control SAQ
This lesson allows you to test yourself on the material covered in the Principles of Process Control lesson and determine the level to which you have met the learning outcomes.
Suggested Response - Q3
** An automated process control system fits into a hierarchy. Each level has a specific focus and a relationship to the components that comprise that particular level.
Describe the purpose of the following components and state the level at which they occur within the hierarchy:
a) The SCADA system
b) A paddle switch at the bottom of a bulk grain silo
c) Ladder logic
d) A flow controller
Response:
a) The SCADA system is responsible for displaying information regarding the process, input of recipes, and other operator functions. Alarms and plant status are also displayed here. The SCADA system operates at the supervisory level.
b) A paddle switch at the bottom of a bulk grain silo will indicate when the silo is empty. This means that a person does not physically have to check, and the silo can be promptly refilled. This is an example of the field level.
c) Ladder logic is a popular PLC programming language. It outlines the steps that a PLC takes in monitoring and adjusting a process. Ladder logic is an example of the control level.
d) A flow controller effects control on the process and is therefore an example of the control level.