202102 attaining proficiency in industrial pressure measurement r7

| Industrial Pressure Measurement | February, 2021 |
© Yokogawa Electric Corporation
Attaining Proficiency in Industrial
Pressure Measurements
Charles Pate
February 4th, 2021

1
Hosts and Presenters
Host Presenter
Nicholas Meyer
Industry Marketing
nicholas.meyer@yokogawa.com
Charles Pate
Pressure Business Development
charles.pate@yokogawa.com
Photo

2
Pressure Basics and
Sensor Technologies

Four Most Common Plant Measurements
3
Pressure Temperature Flow Level

 The amount of force exerted
over a unit of area
4
What is Pressure?
The force may be exerted by liquids,
gases, or solids
P = F/A
P = Pressure F = Force A = Area
Mathematically, pressure is
expressed:

5
Pressure Basics

6
Pressure Transmitters
Absolute DP Gauge

Pressure Terms
• LRL - Lower Range Limit
• Lowest possible value of measurement
• URL - Upper Range Limit
• Highest possible value of measurement
• Range - Measurement window (URL - LRL)
• LRV - Lower Range Value
• URV - Upper Range Value
• Span - Difference of LRV and URV

Terminology - example
 Range Limits
– LRL is the minimum value that a capsule
can measure
– URL is the maximum value that a capsule
can measure
– Range: measurement window
(LRL to URL)
 Range Values
– LRV (4mA) is the lowest value that a
transmitter has been adjusted to measure
– URV (20mA) is the highest range that a
– Span: D of LRV and URV
60 in H2O
12 in H2O
72 in H2O

Terminology - example
 Range Limits
– LRL is the minimum value that a capsule
can measure
– URL is the maximum value that a capsule
can measure
– Range: measurement window
(LRL to URL)
 Range Values
– LRV (4mA) is the lowest value that a
– URV (20mA) is the highest range that a
– Span: ∆ of LRV and URV
60 in H2O
12 in H2O
72 in H2O

Pressure Sensor Types
Two ‘H’ shaped bridges
resonating @ 90 kHz are
located in a silicon substrate
12
Piezoresistive
Capacitance Silicon Resonant
Wheatstone Bridge
T
T
C
C

13
Yokogawa Pressure Transmitter History
Timeline of Yokogawa’s 50 Years of Pressure Sensor Advances
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
2015
Today
DPharp EJX-A
DPharp EJA-E
DPharp EJ
Silicon Resonant
Uni Δ Mark II
Uni Δ
D/P Cell
Capacitance
Force
Balance
DPharp EJA-A
Capacitance
PiezoResistive
Analog Sensor Digital Sensor

14
Pressure Sensor Types Comparison
Principle Capacitance Piezo Resistive Silicon Resonant
Construction
Advantages
 Reliable low-pressure performance and
vacuum performance
 Mature design (used for 50+ years)
 Quick response time
 Easy to manufacture
 Very stable, repeatable output
 Digital signal
 Active sensor
 High signal to noise ratio (40,000 Hz)
 Highly accurate and predictable
 Multi-sensing
Disadvantages
 Electronically complex
 Measures only one PV
 Requires A/D converter
 Low signal-to-noise ratio (only 50 pf)
 Poor overpressure handling
(deformation of metal diaphragm)
 Passive sensor
 Large temperature effect
(prior to compensation)
 Measures only one PV
 Requires A/D converter
 Low signal-to-noise ratio
(only ~2K ohms)
 Poor overpressure handling
 Passive sensor
 Initial design investment
 Relatively complex monolithic
integrated circuit manufacturing
T
T
C
C

Resonant Silicon Sensor Technology is Multi-Sensing
Operating Circuit of a
Resonating Bridge
15
f1 - f2 =
Proportional to
Temperature
(Frequency)
(Frequency)
(Resistance)
Proportional to
Differential Pressure
Proportional to
Static Pressure
f1 + f2 =
R =
f1 f2
Process Pressure

Away From
the Process
16
 Process
temperature
isolation
 Process
pressure
isolation
Thermally Isolated Sensor
Glass
Isolator
Chip
Header
HP Fluid
Pressure
LP Fluid Pressure
Capsule
Body
Isolation
Diaphragm(s)
P1
LP = P2
HP = P1

17
Transmitter Performance
and Calibration

18
What is Real World Performance?
Accuracy is worse
in real world
Laboratory
Ref accuracy
Temp effect SP effect Over pressure
effect
Error
Temp change
Static pressure and Over pressure
Real World
Ref accuracy

Real World Performance = Total Accuracy (TA)
19
Better Definition
𝑻𝑻𝑻𝑻 = 𝑬𝑬𝟏𝟏
𝟐𝟐 + 𝑬𝑬𝟐𝟐
𝟐𝟐 + 𝑬𝑬𝟑𝟑 + 𝑬𝑬𝟒𝟒
𝟐𝟐 + 𝑬𝑬𝟓𝟓
𝟐𝟐
Where:
 E1 = Reference Accuracy of Calibrated Span
 E2 = Ambient Temperature Effects per 50°F change (Zero and Span)
 E3 = Static Pres. Span Effects per 1000 psi change
 E4 = Static Pres. Zero Effects per 1000 psi change
 E5 = Overpressure Effects up to MWP
This is the complete Total Accuracy definition

 Mechanical system within construction
to provide additional overpressure
protection by equalizing the excessive
pressure before it reaches the sensor
20
Silicon Resonant for Best Overpressure Performance
Overpressure rating is up to 2300 psi for
standard 100 in H2O DP
ONLY sensor technology with published
specification for overpressure
 Once stable process conditions return,
these features enable the transmitter to
return to normal operation within the
published specifications:
Pressure sensor
Low
pressure
side
High
pressure
side
Protection
Diaphragm
Seal
Diaphragm
Fill Fluid

Silicon Resonant Multi-Sensing Enables Dynamic Compensation
 Each sensor is unique
 Through rigorous testing, a characterization curve is created, and correction coefficients
are generated for each sensor
 During operation, static pressure and temperature are continuously measured
 The transmitters using the correction coefficients are actively engaged during operation to
compensate for fluctuations in static pressure and temperature in order to greatly reduce
the impact of this change on the transmitter’s output
21
DP
SP
T
Dynamic Compensation
Static Pressure Effect and
Temperature Effect
DPDC
SP
T
Correction Coefficients

Characterization = Better Real-World Performance
Signal correction ensures:
 Precise pressure measurement over the entire range
 High accuracy even after re-ranging
22
Original sensor
characteristic
Output
100%
0%
100%
Input
Output
100%
0%
100%
Input
Original sensor
characteristic
The sensor
corrected with the
characterization
curve

| Document Number| February 29, 2016 |
Copyright © Yokogawa Electric Corporation
23
Long term stability for Performance in the Plant
Field-proven unconditional stability:
EJA-E - 0.1% of URL for 10 years
EJX-A - 0.1% of URL for 15 years
Single crystal silicon: No hysteresis, no
drift.
Stability guaranteed under all working
temperatures, static pressures and
over pressure instances

24
Calculating Calibration Interval
Real World
Performance
(TA)
Time in service
Calibration frequency
Acceptable
performance
Error
(%)

25
Installation
Considerations

Use of impulse lines
 Transfer pressure from process to transmitter
 Thermal protection of transmitter
26
Installation Techniques
Yokogawa’s
Universal Mount for
horizontal or vertical
orientation
Entrained gas
vents away from
transmitter
Impulse lines
filled with water
All liquid drains away
from transmitter
Gas

Installation Techniques
27

Series of related valves
within one body
 Typical configurations
 Block & Bleed
 2-Valve
 3-Valve
 5-Valve
 Designed for:
 Isolation
 Venting
 Reduce the number of potential
leak points
 Enable on-site calibration and
zero-check
28
Instrumentation Manifolds

29
Manifold Body Styles
Threaded
Remote/Inline
Single Flange
Flange x NPT
Double Flange
Flange x Flange
Coplanar

30
Configuration
and Programming

Configuration/Programming
Most vendors will provide configuration or
programming of instrument at no charge or for a
minimal fee
Generally included:
 Calibration range and units
 Linear or square root for output mode and display
mode
 Display scale and units (for units with display)
 Hart protocol selection of HART 5 or 7 when HART
is ordered, and protocol revision is user selectable
 Tag Number
 Software Tag
31

Operation: Programming
For Yokogawa instruments, field guides are available for detailed setup:
32

33
Calibration

Calibration
To check instrument operation and accuracy during periodic maintenance
or troubleshooting:
 Connect the instruments as shown, warm up the unit for at least 5 minutes
(10 minutes for absolute)
34
If the measurement range 0% point is
0 inches or shifted in the positive direction
(suppressed zero), the reference pressure
should be applied as shown in the figure.
If the measurement range 0% point is
shifted in the negative direction (elevated
zero), the reference pressure should be
applied using a vacuum pump.

2
Calibration
 Sensor Trim
 Trim Analog Output
35
Apply reference pressures of 0%, 50%, 100%, 50% and 0% of the
measurement range to the transmitter
Calculate the errors (differences between digital voltmeter readings and reference
pressures) and confirm that the errors are within the required accuracy
As Left As Found, or adjustment required:
1
3

Calibration–Sensor Trim
Zero Trim
A one-point adjustment typically used to compensate for mounting
position effects, or zero shifts caused by static pressure
Full Sensor Trim
A two-point process, in which two accurate end-point pressures are
applied (equal to or greater than the range values), and all output is
linearized between them
 Auto Sensor Trim Applying reference pressure of 0% and 100% of the
measurement range to the transmitter, adjust the lower and upper points
automatically
 Adjust lower pressure value first
36

Calibration–Trim Analog Output
D/A Trim
Carried out if the calibration digital meter does not exactly read 4.000 mA
and 20.000 mA with an output signal of 0% and 100%
 Ex. Adjustment 4 to 20 mA output using a voltmeter
(4mA → 1V, 20mA → 5V)
Reset Trim Adjustment to Factory Setting
The Clear P snsr trim and Clear SP snsr trim commands can reset the trim
adjustment to the setting of initial factory calibrated values
37

38
Sensor Trim

39
Advanced Pressure
Applications

40
DP Level
Remote Diaphragm Seals and
Best Practices

What is a Diaphragm Seal?
A diaphragm seal is a system that attaches to a pressure transmitter that is used
to mechanically transfer pressure from the process to the pressure transmitter.
41

Seal System Make-Up
42
Remote Seal System

Why Do We Use Diaphragm Seals?
 High Temperature Applications
 Corrosive Service
 Isolation from Process for Safety
 Suspended Solids in Process
 Sanitary Connections
 Replacement of Wet Legs
 Ease Cleaning Between Batches
 User Safety
43

Terminology
Diaphragm Seal
 Also known as: remote seal, chemical seal or isolator
Process Wetted
 Diaphragm seal components that come in contact
with the process media; Ex. Diaphragm, lower
housing and o-ring
Non-Process Wetted
 Diaphragm seal components that does not come in
contact with process media; Ex. Upper housing,
assembly hardware
44

Terminology
Diaphragm
 Thin flexible material that separates the process from the instrument (also called:
membrane or sensing element)
System Fill Fluid
 Fluid installed behind the diaphragm and into the instrument. This fluid transfers the
pressure from the diaphragm to the instrument
Flushing Port
 An NPT connection machined into the lower housing. Mainly provides method to clean
the diaphragm and lower housing from settlement (also called: clean-out port or
calibration port)
45

Terminology
Balanced System
 A differential pressure transmitter with two remote seals that are equal in length
Unbalanced System
 Differential pressure transmitter with two remote seals that are not equal in length
 Example:
 A transmitter with a direct mount seal on one side and a capillary seal on the other
 Different size diaphragms or different length capillaries on a transmitter
46

Effects on Response Time
 Capillary Length/Diameter
 Fill Fluid
 Seal Diaphragm Diameter
 Process and Ambient Temperatures
Effects on Accuracy
 Capillary Length/Diameter
 Seal Diaphragm Diameter
 Fill Fluid
 Process and Ambient Temperatures
47
Impact on Your Measurement
System Total Response Time =
Seal System Response +
Transmitter Response
System Total Accuracy =
Seal System Accuracy +
Transmitter Accuracy

Fill Fluid Best Practice: Review Process Conditions
Measurement Range
Types:
 Pressure
 Level
 Flow
Process Temperature and Ambient Temperature
Type of Process Service
 Food
 Chemical
 Water
 Vacuum
48

Temperature Effects
 Smaller diaphragms are less compliant than
larger diaphragms (in majority of cases)
 Less compliant diaphragms provide greater
resistance to the thermal expansion of system
fill fluid, thus creating a larger internal pressure
when a temperature delta is noticed, which in
turn generates a larger zero shift
49
The smaller the diaphragm
is, the more the temperature
shift will be increased

50
Temperature Effects – Advance Yokogawa Solutions
Environmental Compensation Compensating Capillaries Digital Remote Sensors
Characteristic with
remote seal(s)

51
DP Flow Measurement
Technologies

How it Measures Flow
Bernoulli Principle
Increased fluid velocity results in a decreased pressure
52
So, differential pressure across a known
geometry (primary element) that causes
a loss in pressure is proportional to flow

Overview
Simple DP Components
 Primary elements
 Impulse lines
 Secondary element (DP transmitter)
Additional Items
 Pressure/temperature transmitters
 Flow computers/DCS
 Gas Chromatograph
53

Principle of Operation
Primary Element Types
 Orifice plates, venturis, nozzles, pitot tubes and wedge meters
 Restriction of flow in a pipe causes a drop in pressure
54
DP = P1 - P2
P1 P2
Vena Contracta at MIN FLOW Vena Contracta at MAX FLOW
P1 P2

Comparison of Common Primary Elements
55
Primary Flow Element Product Selection
Guide from Solartron ISA

Combination Verabar + Nozzle
 Increases DP over standard Verabar,
which increases the operating range
(turndown) especially in low flow
applications
 Limited straight run requirements
56
Yokogawa and Veris Solution

Consideration: Multivariable Transmitter
Combines:
 Differential Pressure Transmitter
 Static Pressure (Gauge/Absolute) Transmitter
 External Temperature Transmitter
 Flow Computer
57

Pressure includes:
 Differential pressure
 Gage pressure
 Absolute pressure
 Also available in Wireless ISA100 protocol
Used not only for pressure, but also for flow
and level applications
Manufacturing, Flow Test and Calibration Lab
at Yokogawa’s Newnan, Georgia facility
58
Summary

59
Additional Resources

60
Questions?

The names of corporations, organizations, products and logos herein are either registered trademarks or
trademarks of Yokogawa Electric Corporation and their respective holders.
Thank you!
61

202102 attaining proficiency in industrial pressure measurement r7

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