Positioner

A positioner comprising:

• a control output generator calculating a deviation between a valve opening setting value sent from a higher-level device and an actual opening value that is fed back from a control valve that is subject to control, to generate, as a control signal, an electric signal in accordance with the deviation;
• an electro-pneumatic converter converting into a pneumatic pressure signal a control output generated by the control output generator;
• a pneumatic pressure signal amplifier amplifying the pneumatic pressure signal converted by the electro-pneumatic converter and outputting, to an operating device for the control valve, as an amplified pneumatic pressure signal;
• and
• a positioner operating mode identifier identifying automatically whether an operating mode of the positioner is in a positive operating mode wherein the greater the control output the greater the amplified pneumatic pressure signal, or a negative operating mode wherein the greater the control output the less the amplified pneumatic pressure signal.