JPS59108113A - Controlling method of shipment of constant quantity - Google Patents

Abstract

PURPOSE:To secure a shipping quantity highly accurately by closing a shipping control value fully if the difference between the remaining value of the shipment and a flow rate signal is zero when the remaining value obtained from the integrated value of flow rates and a constant quantity setting value is reduced less than a prescribed value. CONSTITUTION:An integrating counter ACT integrates flow rate pulse signals from a flow rate oscillator FS arranged on a shipment pipe line P of fluid. A preset counter PCT subtracts a flow rate signal from a preset value. A digital controller DCT subtracts the counted value of the ACT from the constant quantity setting value CSV to find out the remaining quantity of shipment. When the remaining quantity of shipment is reduced less than the maximum preset value of the PCT, the remaining value is preset on the PCT. When the remaining value is turned to zero, the control valve MV is controlled and closed fully to complete the shipment. Consequently a precise shipping quantity can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a quantitative shipping control method for controlling the shipping of only a predetermined amount of fluid such as fuel or chemicals. It is applied to shipping, and the flow rate of the fluid is monitored using a flowmeter, and when the cumulative flow rate reaches a fixed value, the control valve for shipping is fully closed, and fixed-quantity shipment is automatically carried out. However, conventionally, a fixed period scanning method or a preset counter method is generally used.

In other words, in the fixed-period scanning method, it is monitored whether the shipment amount has reached a fixed value at every fixed sampling period, and when the shipment amount exceeds the fixed value, the shipment is considered complete, and the preset In the counter method, a preset counter with a maximum preset value corresponding to the quantitative value is prepared, and the quantitative value is preset and subtracted according to the shipping amount, and shipping is completed when the count value becomes zero. .

However, in the fixed-period scanning method, in order to control the shipping amount with high precision, sampling must be performed at short intervals, which requires high-speed control calculation processing, which significantly increases the calculation processing load. produce defects.

In addition, with the preset counter method, when the quantitative value is large or when controlling the shipment amount with high resolution, an extremely large capacity preset counter is required, which makes the device expensive and Even if temperature compensation is performed, there are drawbacks such as the fact that the result cannot be reflected in the count value of the preset counter.

The purpose of the present invention is to fundamentally eliminate the drawbacks of the conventional art.The present invention integrates flow rate signals from flow rate transmitters to obtain an integrated value, and then samples the integrated value at regular intervals. The remaining quantity value for shipping is calculated from the integrated value and the quantitative setting value that determines the shipping quantity, and after the remaining quantity value becomes less than a predetermined value, the remaining quantity value is subtracted by the flow rate signal, and the subtraction result is Generates an interrupt signal when it becomes zero,
The present invention provides an extremely effective quantitative shipping control method that fully closes a shipping control valve in immediate response to an interrupt signal.

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 1 is a functional block diagram showing the configuration. The fluid shipping pipe PK is provided with a flow rate transmitter FS of a flow meter and a control valve MY such as a motor valve. A pulsed flow rate signal is sent from the FS according to the fluid flow rate,
While the integration counter ACT performs integration, the preset counter PCT subtracts the flow rate signal from the preset value.

The digital controller DCTK, which consists of a microprocessor, memory, input/output circuits, etc., is equipped with a quantitative setting value CsV-, which determines the amount of shipment, a fixed-cycle program CCP, and an interrupt program INF. By periodic execution, the integration counter AC
The count value indicating the integrated value of T and the quantitative setting value CSV are sampled, and the remaining amount value for shipping is determined by calculating (quantitative setting value) - (count value). When it becomes
While the remaining amount value is preset in the preset counter PCT, when the remaining amount value becomes zero, the control valve MV is controlled and fully closed to complete shipping.

When the count value of the preset counter PCT becomes zero, an interrupt signal is sent out, and in response to this, the interrupt program INF is executed.
Y is controlled to be fully closed.

Figure 2 is a flowchart of the fixed cycle program CCP, which reads the 9 count values of the integration counter ACT and performs correction calculations on the count values according to the type and temperature of the fluid. After calculating the amount of shipment, "memorize the count value after the correction wave" and calculate the remaining amount of shipment by the above calculation, the result is 1.
If the remaining amount -〇' is Yes, the control valve ^M■ is fully closed.

In addition, if 1 remaining amount 20〃 is NO, the remaining amount is determined by performing the "reverse correction calculation on the remaining amount" to obtain the remaining amount and the corresponding count value, and then calculating the remaining amount by "maximum preset value". It is determined whether or not the amount has become less than a predetermined value, and if YES, the remaining amount is set to the preset value in the preset counter "PCT" and the above operation is repeated according to the sampling period.

Therefore, the determination of 1 remaining amount - 〃 is made every time sampling is performed, and if "remaining amount = 0" is Yes, the control valve MV is
is fully closed, shipping is completed, and ゝRemaining amount -〇〃
While NO, the presetting of the remaining amount for the preset counter PCT is repeated on the premise that the remaining amount is less than the maximum preset value of the preset counter PCT.

FIG. 3 is a timing chart showing the operating status of FIG. On the other hand, the remaining amount data Rm calculated by calculating the remaining amount shown in Fig. 2 gradually decreases, and this is the maximum preset value of the preset counter PCT. If it is less than or equal to MPV, preset PST of data Rm to preset counter POT is performed.

Further, the count value (c) of the preset counter PCT is subtracted by the flow rate signal and gradually decreases, and when it becomes zero, an interrupt signal (d) is sent, and the control signal (e) is accordingly The control valve MV is therefore fully closed.

Therefore, the count value (b) is read as data bm according to the sampling signal (,), and before this becomes equal to the quantitative setting value C8v and it is determined that "remaining amount - 0" has become Yes. Also, as soon as the count value of the preset counter PCT becomes zero, the control valve MY becomes fully closed, so that the shipment amount is maintained accurately.

In addition, the preset counter PCT has the remaining amount data Ry.
Since the preset is performed after yt becomes equal to or less than the maximum preset value MPV, there is no need for a counting capacity corresponding to the total shipment amount, and it becomes possible to use a small capacity color/receiver.

Note that since the result of performing the ``inverse correction calculation on the remaining amount'' is preset in the preset counter PCT, the count value indicating the remaining amount is accurate and a highly accurate shipment amount can be ensured.

In addition, since the preset counter PCT is repeatedly preset, it is possible to change the quantitative setting value during shipping, and the preset value can be updated according to temperature changes by reverse correction calculation for 1 remaining amount. Therefore, even if temperature changes occur during shipping, the amount shipped will be accurate.

In Figure 2, the preset counter 'PC'
Various modifications are possible, such as presetting the remaining amount to T only once, or omitting the 1' correction calculation step if high precision is not required.

As is clear from the above explanation, according to the present invention, the counting capacity of the preset counter is reduced and the shipping amount is regulated by the preset counter.
It is possible to make the sampling period long with a constant 9-cycle program, the operating load on the digital controller is reduced, equipment costs can be easily reduced, and a remarkable effect has been achieved in quantitative shipment control of various fluids. It will be done.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Figure 1 is a functional block diagram, Figure 2 is a flowchart of a periodic program, and Figure 3 is a flowchart of a periodic program.
The figure is a timing chart showing the operating status of Figure 1. OFS...Flow rate transmitter, MV...Control valve, ACT
@・-1 integration counter, PCT...preset counter, DCT...-digital controller, C8
v: Quantitative setting value, CCP: Fixed cycle program, INF: Interrupt program. Patent applicant: Yamatakeno Newel Co., Ltd. Agent: Kazuha Yamakawa (1311 people) Figure 1 Figure 2 Figure 3 (e)゛

Claims (1)

[Claims] (11) After integrating the flow rate signals to obtain an integrated value, the integrated value is sampled at regular intervals, and at each sampling time, the integrated value is calculated from the quantitative setting value that determines the shipping amount. Calculates the remaining amount value for shipping, subtracts the flow rate signal from the remaining amount value after the remaining amount value becomes less than a predetermined value, and issues an interrupt signal when the result of the subtraction becomes zero. A quantitative shipping control method characterized by fully closing a shipping control valve in immediate response to the interrupt signal generated by the interrupt signal. (2) The remaining amount value to be subtracted is updated every time sampling 2. A quantitative shipping control method according to claim 1, characterized in that: