Operating and Ambient Temperature

The “operating” or “ambient” temperature range denotes the temperature extremes to which the pressure transmitter’s body will be exposed when operational. For instance, a typical range for standard pressure transmitters is -20 to +80°C. Deviating from this range may lead to significant output signal drift or complete failure of the transmitter. Even brief exposure can cause permanent damage. Factors such as the material of the transmitter body (which can conduct heat from warm media) and cable materials (which may become brittle in extreme cold) need to be considered when selecting a suitable pressure transmitter.

Storage Temperature

A storage temperature specification is also provided, often wider than the operating temperature range, as electronic circuits are less vulnerable to extreme temperatures when not in use. However, the specified storage temperature may be lower if the manufacturer includes packaging and transport simulation tests.

Media Temperature

The media temperature directly affects the pressure sensor’s performance and accuracy. It is essential to choose a transmitter with a media temperature range exceeding the expected minimum and maximum media temperatures to avoid significant errors or failure. Specifications typically range from -30 to +100°C, but options for higher temperatures are available, including cooling elements, siphons, diaphragm seals, and capillary tubes.

Compensated Temperature Range

The compensated temperature range is where the sensor’s internal circuitry is designed to limit temperature error to a specified level. For example, a pressure transmitter with a media temperature range of -30 to +100°C may have a compensated range of -0 to +80°C, within which the temperature error is no more than 0.2% of span per 10°C change. Outside this range, the error can be significantly higher.

Calibration Temperature

Finally, the calibration temperature is the temperature to which the transmitter is exposed during calibration during manufacturing and serves as the basis for calculating error within the compensated pressure range. Some manufacturers offer options for calibration temperature tailored to specific applications. For instance, a pressure transmitter calibrated at a standard temperature of 15-25°C will not introduce additional temperature error when operated within this range. If the application involves a constant temperature of 80°C, factory calibration at this higher temperature can enhance the transmitter’s performance in high-temperature environments.