Transmitter with multifunction adjustment

摘要

A process variable transmitter which has a manual adjustment for span and zero or the like. The adjustment has a finer adjustment range where the output changes responsive to changes in the position of the adjustment. The adjustment has a coarse range where the transmitter output changes automatically as a function of time to provide coarser adjustment. An operator can move the back and forth between the adjustment ranges until a desired output value is observed. When adjustment is complete, the operator can manually select the desired transmitter output value and then a selection circuit stores the setting in non-volatile memory. After a setting is stored, the transmitter output is not sensitive to movement of the manual adjustment, but is instead controlled by the stored setting.