| 摘要 |
PURPOSE:To control a flow rate accurately even when control cycles are short by sending an interruption signal from a preset counter to a CPU once the flow rate of fluid fed to a tank attains to a target value and then opening an operation valve fully. CONSTITUTION:When the amount of the heavy oil in the tank attains to a preset range value, a CPU13 finds the difference between a target flow rate and the amount of the heavy oil in the tank and sets its count number in a preset counter 20. This counter 20 counts a pulse signal from a flow meter 4 and counts down the preset count number. When the count value decreases to zero, the counter 20 sends the interruption signal to the CPU13. Then, the CPU13 sends a signal for closing the operation valve 5 to a D/A converter 16 through a bus 15. This signal is converted into an analog signal by the converter 16 and the signal is sent to the operation valve 5, which is closed. |
