1. Signal Transmission and Conversion, Test Review - Agenda
Activity
Estimated Time
1. Agenda 5
2. Learning Objectives
3. Signal Transmission 50
BREAK 10
4. Signal Conversion
5. Signal Conversion Continued 40
6. Summary and Wrap-Up
7. Additional Activities
8. Lab Activities
Slide 1
Instrumentation 2 – Session 3

2. Objectives (page 1) Recall the purpose and operation of transmitters.
Describe methods for protecting integrity and reliability of signal transmission:
heat tracing
shielding
insulation
materials of construction
safety concerns
Recall types of common transmitters:
mechanical
pneumatic
electrical
digital
Slide 2
Instrumentation 2 – Session 3

3. Objectives (page 2)
Recall the purpose and operation of signal converter equipment.
Describe how wet leg instrument lines are “zeroed out”.
Describe the effect on a primary sensing element that uses a wet-leg/sealing liquid when the density of the sealing liquid changes.
Discuss methods used to ensure dry-leg remains dry.
Perform scaling calculations:
Linear
Non-linear
Slide 3
Instrumentation 2 – Session 3

4. Transmitter Question Does the transmitter measure:
Output of the process
The input of the process
Slide 4
Instrumentation 2 – Session 3

5. Answer Does the transmitter measure: Output of the process
The input of the process
Slide 5
Instrumentation 2 – Session 3

6. Four Aspects
Correct selection of material to construct the transmission medium
Effective temperature control
Effective insulation
Effective shielding
Slide 6
Instrumentation 2 – Session 3

7. Materials of Construction
Includes metals, synthetics or natural resources used to form or fabricate a component, device or system.
For example:
Wood
Steel
Plastic
rubber
Slide 7
Instrumentation 2 – Session 3

8. NACE
Slide 8
Instrumentation 2 – Session 3

9. Heat Tracing
Slide 9
Instrumentation 2 – Session 3

10. Insulation
Slide 10
Instrumentation 2 – Session 3

11. Shielding
Shielding
Slide 11
Instrumentation 2 – Session 3

12. Grounding
Slide 12
Instrumentation 2 – Session 3

13. Safety Equipment Fires Thermal Burns (personal)
Sensor Damage (loss of measurement and control signals
Process Piping Damage (erosion and corrosion)
Slide 13
Instrumentation 2 – Session 3

14. Transmission Signals Pneumatic Hydraulic Capillary
Electromagnetic of Sonic
Electrical or Electronic
Pneumatic Binary
Electrical or Electronic Binary
Data links
Slide 14
Instrumentation 2 – Session 3

15. Instrument Symbols
Slide 15
Instrumentation 2 – Session 3

16. Conversion Symbols I/P – Current to Pressure P/I – Pressure to Current
I/E – Current to Voltage
E/I – Voltage to Current
I/F – Current to Frequency
F/I – Frequency to Current
E/F – Voltage to Frequency
F/E – Frequency to Voltage
Slide 16
Instrumentation 2 – Session 3

17. Differential Pressure Transmitter
Zeroed Out
Zero Suppression
+50 to +225 inches of water column
Zero Elevation
-65 to +135 inches of water column
Slide 17
Instrumentation 2 – Session 3

18. Impulse Line Question
What is the effect when one impulse line is required for the measurement and when two impulse lines are required?
Slide 18
Instrumentation 2 – Session 3

19. Answer
What is the effect when one impulse line is required for the measurement and when two impulse lines are required?
A. The effect is zero calibration shifts in either case; one impulse line or two. Density changes in the seal liquid cause calibration shifts in the transmitter.
Slide 19
Instrumentation 2 – Session 3

20. Keep it Dry Heat Tracing Purging Elevation changes to the impulse line
Slide 20
Instrumentation 2 – Session 3

21. Scaling Upper Range Value (URV) Lower Range Value (LRV) Range Span
Slide 21
Instrumentation 2 – Session 3

22. Linear Scaling VALUEB = x SPANB + LRVB VALUEA – LRVA SPANA Slide 22
Instrumentation 2 – Session 3

23. Non-Linear Scaling Flow Rate Percent d/p Slide 23
Instrumentation 2 – Session 3

24. Calculate Flow Rate
To change 50% flow rate into percent d/p, do the following steps:
Output mA = (% flow rate 100)2 x 16 mA + 4 mA
Output mA = (50% 100)2 x 16 mA + 4 mA
Output mA = (0.25) 2 x 16 mA + 4 mA
Output mA = x 16 mA + 4 mA
Output mA = mA
Slide 24
Instrumentation 2 – Session 3