Reference Accuracy
Reference accuracy is a baseline accuracy specification that does not include process effects that can contribute to transmitter errors such as temperature and static pressure effects. Reference accuracy is expressed as a percentage of the span and includes terminal-base linearity, hysteresis, and repeatability. The reference accuracy is established under reference conditions. These reference conditions are declared with the reference accuracy specification and include temperature, static pressure, turn-down, and the material of construction. Yokogawa's reference accuracy does not include temperature or static pressure reference conditions since the reference accuracy is valid for the entire temperature and static pressure range of the transmitter.
Reference accuracy is a liberal accuracy statement and commonly misused to evaluate one transmitter versus another. A better evaluation specification would be Total Installed Accuracy; it accounts for the actual operating condition on the transmitter.
Refer to the Yokogawa General Specification documents for reference accuracy of each transmitter.
Example from a EJA110E and EJX110A differntial pressure transmitters.
Reference Accuracy
Reference conditions: Zero-based calibrated span, a linear output, wetted material code S, and silicone fill fluid.
