| 摘要 |
PURPOSE:To easily attain a constant pressure control concerning a flow quantity in which every flow quantity is not constant by replacing either of upper and lower values of set flow quantity to a calculated flow quantity value and calculating a flow quantity value to be newly controlled with a second dichotomy. CONSTITUTION:By a pressure value setting means 24, the pressure value to be controlled is set and by a flow quantity value setting means 25, upper and lower flow quantity values corresponding to upper and lower pressure values of a setting pressure value are set. With a control flow quantity value calculating means 27, the flow quantity value to be controlled by a dichotomy based on the upper and lower flow quantity values is calculated, a signal is sent to a control valve, and the control valve is controlled by the flow quantity of the calculated flow quantity value. A pressure after it is controlled by a pressure measuring means 20 is measured, the setting pressure value and the measuring pressure value are compared by a pressure comparing means 26, at the time of dissidence, either of upper and lower flow quantity values is replaced to the calculated flow quantity value by the control flow quantity value calculating means 27 and the flow quantity value to be newly controlled with the second dichotomy is calculated. Thus, concerning the flow quantity in which every flow quantity is not constant, the constant pressure control is executed easily.
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