Yokogawa Electric Corporation is dedicated to developing the most advanced control and instrumentation products, (and systems), in the world. With their establishment in the United States in 1957, Yokogawa Corporation of America has become a leading manufacturer and supplier for the North American market in the fields of automation, measurement, and control. As a major industrial automation and test and measurement company, Yokogawa anticipates the needs of the times, continually tackling new challenges and exploring new markets in order to provide the customer-centric solutions.

1. Real-Time Dynamic Compensation for Static Pressure Effects
Performance under pressure - DP Transmitter Static pressure (SP) is applied equally to both the high-pressure side
and the low-pressure side of a DP transmitter and can vary the linear
Accurate measurement is vital to efficient plant operation and plant characteristics of the DP signal output. The effect is called Static
safety. When selecting a transmitter, a lot of attention is paid to the Pressure Effect . This characteristic has both Zero Effect and
Reference Accuracy noted in supplier's specification documents. Span Effect components.
Reference Accuracy gets its name because the accuracy is based
on a set of reference conditions. The reference conditions dictate
a certain temperature, humidity, and static pressure for the
Reference Accuracy to be measured in a laboratory setting. In the
real world, DP Transmitters are rarely installed in a laboratory
and never under the rigid confines of those reference conditions; therefore,
Real-world Performance (RWP) is always worse than the Reference
Accuracy. To improve RWP, all smart transmitters on the market SP Effect
compensate for variations in temperature; but, Yokogawa's sensor
used in the EJA-A series, EJX-A series, and EJX-B series is unique in
the market place because it can compensate for effects in static
pressure change as well. This ability is referred to 0% 100%
Real-time Dynamic Compensation .
Static Pressure Effects SP = 100
Using differential transmitters to measure flow and tank level are
examples of applications where variations in static pressure can effect 100 100 100 200
the differential pressure readings of a transmitter. 0%
SP = 0
0 0 0 100
0%
PTN1011.003a
To quantify the impact, Real-world Performance (RWP) can be
calculated per published specifications and process conditions. RWP is
a combined error of Reference Accuracy (E1), Temperature Effect (E2),
Static Pressure Zero Effect (E3) and Static Pressure Span Effect (E4).
Competitors state that the static pressure zero effect (E3) can be
PTN1011.001a zeroed at line static pressure during the setup of the transmitter.
In many flow measurements or process level applications, static
pressure is not maintained at a constant value. As operational
conditions change, the static pressure exerted on the DP transmitter
varies. Hence, the static pressure zero effect (E3) cannot always be
cancelled by zeroing at line static pressure during setup. This effect
cannot be neglected when evaluating the real-world performance.
Yokogawa's Full Dynamic Compensation
Yokogawa's silicon resonant sensor is a true multi-sensing platform.
It can measure differential pressure, static pressure, and temperature
in one compact sensor chip. This multi-sensing sensor allows
the transmitter to use correction coefficients stored in the sensor's
ROM to compensate for fluctuations in static pressure and
temperature to reduce the static pressure and temperature effects.
The correction coefficients are unique to each sensor and are
PTN1011.002a generated at the factory through rigorous testing (See Figure 1).
LH.091412.01a FGP-290 2nd Edition 09/2012
LH.012711.a
Static Pressure Zero and Span Effect
Input (DP)
ERROR(%)
Flow Measurement
ΔP ≈ Flow²
Level Measurement
ΔP ≈ Process Level
E3: SP Zero Effect
E4: SP Span Effect
100%
100%
Field Instruments
www.yokogawa.com/us

2. Alternate Sensor Technology
Capacitive sensor technology used in the marketplace is not capable
of multi-sensing. It can only measure differential pressure. The DP
transmitters using this type of technology incorporate a resistive
temperature sensor near the capacitive sensor to compensate for
temperature fluctuations; but, they do not add a separate sensor to
measure static pressure for static pressure fluctuations. Therefore,
these transmitters are not capable of minimizing the static pressure
effect (See Figure 2).
Figure 1 Yokogawa's Multi-sensing Resonant Sensor Technology
Transmitter
Silicon
Resonant
Sensor
Figure 2 Capacitive Sensor Technology PTN1011.003a
Transmitter
Capacitive
Sensor
RTD
Not measured Static Pressure is not measured; therefore it is not compensated for.
PTN1011.004a
Figure 3 Comparison of Real-world Performance
Conclusion
Even in high static pressure applications, Yokogawa's EJA-A / EJX-A /
EJX-B series dramatically reduces the static pressure effects and provides
superior total performance. Using the published specifications, the Real-
world Performance can be calculated for comparative estimates
(See Figure 3). Note that the Reference Accuracy is the smallest component
of the calculations.
E1: Reference Accuracy Calibrated Span: 0 to 1500 inH ₂O
E2: Temperature Effect Static Pressure: 1,200 psig
E3: Static Pressure Zero Effect PTN1011.005a
E4: Static Pressure Span Effect
LH.091412.01a FGP-290 1st Edition 09/2012
Process
Process
www.yokogawa.com/us
Field Instruments
Correction Coefficients
Dynamic Compensation
Temperature Effect
&
Static Pressure Effect
Primary Variable:
Dynamic Compensated
DP Signal
(4 to 20 mA)
Differential Pressure
Differential Pressure
Temperature Temperature
Static Pressure Static Pressure
Differential Pressure
Temperature
Static Pressure
Differential Pressure
Temperature
Temperature
Correction Coefficients
Temperature Effect
Compensation
Digital /Analog
Conversion
Secondary Variable:
Static Pressure
(Digital Protocol)
Third Variable:
Capsule Temperature
(Digital Protocol)
Digital /Analog
Conversion
Analog /Digital
Conversion
Primary Variable:
Temperature Compensated
DP Signal
(4 to 20 mA)
Secondary Variable:
Temperature
(Digital Protocol)
EJX110A
EJA110A
Capacitive
Sensor
Transmitter
RWP = E1+E2+E3+E4
0.0% 0.5% 1.0% 1.5% 2.0% 2.5%