Which of the following is usually adjusted first when calibrating an electronic pressure transmitter?

When calibrating an electronic pressure transmitter, the first adjustment typically made is the zero setting. This is crucial because zeroing establishes a baseline for accurate measurements. By setting the zero point correctly, any pressure measurements taken subsequently will reflect the true pressure relative to this baseline.

In practice, if the zero is not set properly, the readings can be consistently offset, leading to significant inaccuracies. After the zero has been adjusted and verified, other parameters such as span and linearity can be adjusted to further refine the accuracy of the transmitter across its operating range.

While options like span and linearity are essential for ensuring that the transmitter's output accurately matches the input pressure across its full range, they are secondary to the zero adjustment. The range itself is a broader concept that encompasses both the minimum and maximum limits for the transmitter, which will also be influenced by the zero and span settings. Therefore, proper calibration begins with accurately establishing the zero.