1. Instrumentation Process Control
PPT 110

2. The Objective
MAINTAIN THE PROCESS AND THE ELEMENTS OF THE PROCESS WITHIN WELL-DEFINED LIMITS OF VARIATION

3. Process Control

4. Process Control

5. Processing Steps Automatically controlled
Electronic/Pneumatic Instrumentation Loops
Supervisory Control

6. The Control Loop Sensor Controller Control Element Measures X
Transmits signal to controller
Controller
Compares the signal from sensor with the set point
Determines error and transmits signal to the control element
Control Element
Actuates toward reducing the element
Repeat the process

7. Process Control

11. Sensors Measure variable directly Measures a related property
Converts the relationship from the principle to the desired variable
See Table for variables to principles

12. Basis Weight and Moisture

13. Controllers 3-15 psi signal 4-20 ma signal Set point Response Time
Lag-lead requirements
Modes of control
Proportional band (gain)
Reset (integral)
Rate (derivative)
Feedback/feed forward

15. More about Control Control Element Control Concepts Automatic Valve
Cascade
Primary and Secondary controller influence
Primary and Secondary variable
Ratio
One variable at fixed ratio to another variable
Cutback (auto selector)
Control element manipulated as an override
Avoid going above a preset limit - safety

16. Control Systems Pneumatic Electronic PCS or DCS New Control Room
Cheaper, equally sensitive and reliable
Electronic
Distance-no problem (controller/instrument)
Computer to computer
PCS or DCS
New Control Room

17. Control Room