What is the term for a differential pressure transmitter calibrated from -10 to +10 InH2O?

The term "elevated zero" refers to a differential pressure transmitter that is calibrated to begin its measurement range above zero pressure. In this case, when the transmitter is calibrated from -10 to +10 inches of water (InH2O), the negative value indicates that the zero point is set above the lower limit of the measurement range. This configuration is typically used when measuring pressures that can fall below atmospheric levels, allowing for a range of measurements centered around a zero point that is elevated relative to comparable measurements.

This calibration setup is helpful in applications where negative pressure needs to be monitored, as it provides a more direct reading of pressure differentials rather than having a zero point that is at the baseline or absolute zero. Using an elevated zero enables the technician to accurately account for both negative and positive pressure differentials from a specified reference point above zero, making it especially useful in various industrial control applications.

In the context of the other options, suppressed zero would imply a range that starts below zero, an incorrect calibration refers to a situation where the device does not measure according to its intended specification, and a setpoint adjustment relates to altering the established value at which a control system is triggered, which does not specifically pertain to how the transmitter is calibrated.