Yamatake Corporation

Fumio Nagasaka

Shinichi Akano

Takashi Nomiyama

Masato Kuroda

Yasuo Kumeda

A field apparatus for controlling a controlled element includes a diagnosis unit for diagnosing abnormality of the field apparatus and/or the controlled element and a bidirectional digital communication device to send a digital signal which shows a diagnosis result to outside and to receive a digital signal from outside in order to execute a control of the controlled element. Other predetermined functions are effected based on a command signal in the form of an analog signal received from outside by a analog communications device of the apparatus. Electric power for operation is supplied through a switching means that can switch either a electric power that is supplied by the analog communications device or a electric power that is supplied by the bidirectional digital communication device.

Field apparatus

A temperature information detecting device for an angle sensor is provided for detecting only temperature-dependent components based on middle-point potentials when a constant current is supplied to a bridge circuit for an angle sensor, for acquiring a temperature of the angle sensor from the temperature-dependent components, for employing compensating information corresponding to the acquired temperature without separately providing any additional temperature sensor, and for making temperature compensation of the output of the temperature sensor in automatically controlling the valve opening of a flow control valve.

Temperature information detecting device for angle sensor and position detecting device

An electropneumatic positioner includes a data processing control section and an electropneumatic converter. The control section includes first and second position determining sections and a signal setting section. The first position determining section obtains the valve opening degree positions of a regulating valve as the minimum and maximum valve opening degree positions which are set when a driving signal for conversion from an electrical signal into an air pressure is set to the minimum signal and the maximum signal. The second position determining section obtains the valve opening degree position of the valve which is set when the driving signal is the minimum signal on the basis of the relative positional relationship between the obtained minimum and maximum valve opening degree positions and the valve plug form of the valve. The signal setting section sets a relationship between the maximum and minimum signals of electrical signals and full opening and closing directions corresponding to valve opening degrees of the valve.

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Tokyo, Japan

Fumio Nagasaka