Pressure measurement accuracy is critical in demanding environments, OEM applications, and high-purity semiconductor processes. Two key factors that impact accuracy are zero shift and span shift in pressure transmitters and pressure transducers. In this article, we’ll explore what these shifts mean, their common causes.
What Are Zero Shift and Span Shift?
When a pressure sensor is first installed or after prolonged use, it may exhibit output errors:
Zero Shift – The error in the sensor’s output when measuring the lowest pressure value in its range.
Span Shift – The error in the sensor’s output when measuring the full-scale pressure value.
The larger these shifts, the less accurate the pressure readings. Conversely, a high-precision pressure transducer minimizes these shifts for reliable measurements.
These shifts are typically expressed as a percentage of the Full-Scale Output (FSO):
Zero Shift = ± (Zero Output Error / FSO) × 100%
Span Shift = ± (Full-Scale Output Error / FSO) × 100%
FSO = Full-Scale Output – Zero Output
(Example: For a 4-20mA output, FSO = 20mA – 4mA = 16mA)
4 Common Causes of Zero and Span Shift in Pressure Sensors
Several factors contribute to these shifts in pressure transmitters and transducers:
1. Manufacturing Tolerances
Even high-quality pressure sensors can have slight imperfections in sensing elements or electronic components due to manufacturing variances. These tolerances may cause initial zero or span deviations.
2. Environmental Factors
Temperature fluctuations and humidity changes can cause material expansion/contraction inside the sensor, leading to output drift. For example:
High-temperature pressure transducers must compensate for thermal effects.
Humidity-resistant pressure transmitters prevent moisture-induced errors.
3. Electromagnetic Interference (EMI)
Electrical noise from power lines, RF signals, or lightning can disrupt sensor performance. Ziasiot® PT210 and PT216 pressure transmitters feature EMI-resistant designs to maintain signal integrity in noisy environments.
4. Mechanical Stress and Drift
Repeated pressure cycles or mechanical strain can deform the sensor diaphragm over time, causing baseline drift. Industrial-grade pressure sensors must withstand these stresses for long-term stability.
How Ziasiot Ensures Reliable Pressure Measurement
Since 1999, Ziasiot has been a trusted provider of precision pressure transducers and transmitters, offering:
High-accuracy sensors with minimal zero/span shift
Robust designs for harsh environments (OEM, semiconductor, and industrial applications)
Global support with fast, localized service
Explore our solutions:
https://www.pressuressensors.com/
Contact Sales: [email protected]