1. Control Loops: Primary Sensors, Transmitters, and Transducers - Agenda
Activity
Est. Time
1. Agenda 5
2. Learning Objectives
3. Test Review 10
4. Introduction to Primary Sensors, Transmitters and Transducers 15
5. Component Purpose and Operation
BREAK
6. Transmitter Signals and Scaling 30
7. Transducers and Signals
8. Pneumatic and Electrical Signals
6. Control Schemes and Control Loops 40
7. Summary and Wrap-up
8. Additional Activities 50
9. Lab Activity
Instrumentation I - Session 9

2. Session 9 - Objectives
1. Describe the relationship between the measuring instruments (pressure, temperature, level, and flow) and their role in the overall control loop process.
2. Describe the purpose and operation of the transmitter (D/P Cell) in a control loop.
3. Discuss differential pressure in relation to the process input to the transmitter.
4. Compare and contrast the transmitter input and output signals.
5. Describe the function of a current to pneumatic transducer (signal converter).
6. Describe the relationship between a 3 psig to 15 psig air signal and a 4 ma to 20 ma electric signal.
7. Given a process control scheme, explain how a control loop functions.
Instrumentation I - Session 9

3. Primary Sensors, Transmitters and Transducers
Instrumentation I - Session 9

4. Sensors
Instrumentation I - Session 9

5. Transmitters
Instrumentation I - Session 9

6. Differential Pressure and the Transmitter
Instrumentation I - Session 9

7. Transmitter Signals
Instrumentation I - Session 9

8. Scaling
Instrumentation I - Session 9

9. Scaling Terms
Upper Range Value (URV) – The number at the top of the scale. Expressed as one number.
Lower Range Value (LRV) – The number at the bottom of the scale. Expressed as one number.
Range – Range defines the set of values that exist between the LRV of a scale and the URV of a scale. It is expressed as two numbers. (Example 50 psig to 150 psig)
Span – Span is the algebraic difference between the upper range value of a scale minus the lower range value value of a scale expressed as one number. (Example: If URV=150 psig and LRV=50 psig, then Span=100psig)
Instrumentation I - Session 9

10. Calculating the Output of a Transmitter
Instrumentation I - Session 9

11. Transducers
Instrumentation I - Session 9

12. Transducer Signals
Instrumentation I - Session 9