Valve positioner with current allocating device

A positioner for receiving the supply of an electric current through a pair of electric wires from a higher-level system, and for controlling the degree of opening of a regulator valve in accordance with the value of the supply electric current, comprising:

• a constant voltage circuit producing a constant voltage as a local operating power supply from the supply electric current;
• a plurality of function circuit portions connected in parallel with the constant voltage circuit;
• a supply electric current detector detecting, as the present supply electric current, an actual value for the supply electric current;
• a surplus electric current allocating device evaluating whether or not there is, in the detected present supply electric current, surplus electric current that can be directed to the function circuit portion, and, if there is surplus electric current, allocating the surplus electric current to the function circuit portion;
• and
• a storage device categorizing, into a plurality of electric current ranges, the range of electric currents that can be assumed by the supply electric current, and storing a table wherein a combination of the function circuit portions to which the surplus electric current is allocated is established for each category of electric current range,
• wherein the surplus electric current allocating device ascertains the category of electric current range to which the detected present supply electric current applies, reads out, from the table, the combination of function circuit portions established for the applicable electric current range category, and allocates the surplus electric current to the function circuit portions of the combination that has been read out.