Can A Pressure Transmitter With High Turndown Ratio Measure All Pressures Accurately?
A pressure transmitter with a high turndown ratio can measure pressures accurately over a wide range, but there are some important considerations and limitations to keep in mind.
The turndown ratio is the ratio of the maximum pressure that the transmitter can measure to the minimum pressure it can measure accurately. A high turndown ratio, such as 100:1 or higher, means that the transmitter can measure pressures accurately from a very low value to a very high value within its specified range.
However, the accuracy of the measurement at the lower end of the range may be affected by several factors, such as:
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Sensor resolution: At very low pressures, the sensor’s resolution may become a limiting factor, leading to reduced accuracy or increased noise in the measurement.
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Environmental factors: Factors such as temperature fluctuations, vibrations, and mounting position can have a more significant impact on the accuracy of low-pressure measurements.
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Zero drift: Over time, the transmitter’s zero point may drift, affecting the accuracy of low-pressure measurements more significantly than higher pressures.
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Span calibration:** The accuracy of low-pressure measurements can be improved by calibrating the transmitter’s span to a lower range, but this may limit the maximum pressure that can be accurately measured.
To ensure accurate measurements across the entire range, it is essential to:
- Properly size the transmitter for the expected pressure range, considering both the minimum and maximum pressures.
- Follow the manufacturer’s recommendations for installation, calibration, and periodic maintenance.
- Account for environmental factors and implement measures to minimize their impact on the measurement.
- Consider using specialized low-pressure transmitters or differential pressure transmitters for very low-pressure applications if high accuracy is required.
- while a pressure transmitter with a high turndown ratio can measure pressures accurately over a wide range, the accuracy at the lower end of the range may be affected by various factors. Proper selection, installation, and maintenance are crucial to ensure reliable and accurate measurements across the entire pressure range.