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Title:
VALVE POSITIONER AND ELECTRIC-PNEUMATIC CONVERTER
Document Type and Number:
Japanese Patent JP2000304148
Kind Code:
A
Abstract:

To increase current distribution for an electric-pneumatic conversion module by providing a variable impedance circuit having low impedance in a DC area and having high impedance in a digital communication frequency band, the electric-pneumatic conversion module and an impedance control circuit.

A series circuit of a variable impedance circuit 3 and a shunt regulator 4 generating internal power supply voltage V2 is connected with input terminals T1, T2. An impedance control circuit 1 is provided so that inter-terminal voltage of these input terminals T1, T2 may be controlled to substantially constant voltage of normal 12 V or below. A current regulator circuit 33 to be connected with the variable impedance circuit 3 in parallel is provided, a signal which is outputted from a microcomputer 9 and is after a D/A conversion is converted into a current signal, an electric-pneumatic conversion module 14 is made to output the signal and opening of a valve 16 is controlled. The position of this valve 16 is feedback-controlled in accordance with an output signal of a position sensor 12 detecting the position.


Inventors:
Saito, Yoji
Application Number:
JP1999000110779
Publication Date:
November 02, 2000
Filing Date:
April 19, 1999
Export Citation:
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Assignee:
YOKOGAWA ELECTRIC CORP
International Classes:
F15B5/00; F15B9/09; F16K31/04; F16K31/06; (IPC1-7): F16K31/04; F15B9/09; F16K31/06