JPH0769182B2 - Pulse signal processor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention measures the interval of pulse signals generated from a flow meter or the like installed in an industrial process, and calculates an instantaneous value corresponding to the flow rate at that time. To improve the pulse signal processing device.

<Prior Art> Each time a pulse signal is applied, the operation of the conventional pulse signal processing device that measures the interval with the previously applied pulse signal and calculates the instantaneous value will be described with reference to the time chart of FIG. explain.

Assuming that the interval between the pulse signal P1 and the pulse signal P2 provided from an external device such as a flow meter is t1, the interval t1 is measured for the first time when the pulse signal P2 is provided, and the instantaneous value v1 (ts / t1; ts pulse period span) is calculated. Next, when the pulse signal P3 is given, the interval with the pulse signal P2
t2 is measured, and the instantaneous value v2 (= ts / t2) is calculated at this time. The same applies hereinafter.

<Problems to be Solved by the Invention> In the conventional device, as described above, the pulse signal P
Only when is given a new instantaneous value v.

However, when the pulse signal P generated from a flow meter or the like is targeted, the instantaneous value v ′ of the actual flow rate is the previous pulse signal P.
It corresponds to the time value ti from the occurrence of (i-1) to the occurrence of the pulse signal Pi this time.

That is, the correct instantaneous values v1 'and v2' in FIG.

Therefore, in the conventional device, the timing for calculating the instantaneous value is delayed once, and when the value v is passed through a filter such as a first-order delay, this delay accumulates and the correct instantaneous flow rate value cannot be obtained.

Further, as shown in FIG. 6, when the pulse signal P is interrupted, the previous value vn is retained so that the output (instantaneous value v) becomes 0% when an appropriate time tL elapses. When monitored externally, the output suddenly indicates 0% at some point, which may cause confusion in peripheral devices.

The present invention solves the above problems, and an object thereof is to realize a pulse signal processing device that can calculate a value close to a correct instantaneous value.

<Means for Solving the Problems> The present invention, which solves the above problems, stores the previous pulse cycle and determines whether the pulse cycle measured by the pulse signal given this time exceeds the previous pulse cycle. The value is determined and the instantaneous value is updated, and its configuration is as follows.

That is, a time counting means for receiving a pulse signal and counting the pulse cycle thereof, and a storage means for updating the value stored at present every time the pulse signal is applied to the value of the previous pulse cycle measured last time and storing the value. And comparing means for comparing the count value of the time counting means with the value stored in the storing means, and when the pulse signal is given, the instantaneous value of the pulse period is calculated from the count value of the time counting means. If a signal indicating that the count value exceeds the value stored in the storage means before the pulse signal is given by the calculation means is given from the comparison means, A pulse signal processing device, comprising: a calculating unit that calculates an instantaneous value of a pulse period.

Further, as the period in which the pulse signal is given, the time possessed by a plurality of pulse signal groups may be averaged to obtain the pulse period.

<Operation> In the pulse signal processing device of the present invention, the previous pulse period is stored in the storage means, and if the current pulse signal is not input even if it exceeds the stored pulse period, pulse input is performed at this point. If so, the instantaneous value is updated.

<Embodiment> FIG. 1 shows the configuration of a pulse signal processing apparatus embodying the present invention.

In the figure, 1 is a pulse detection unit that detects the presence or absence of a pulse signal P, 2 is a timer that is reset / restarted by the detection signal of the pulse detection unit 1, and 3 is a timer 2 at this time that is detected by the detection signal of the pulse detection unit 1. Storing the value t of tz as tz, 4 always stores the value tz of the storage 3 and the value t of the timer 2.
Comparing with, and performing comparison detection when t> tz, the comparison unit 5 receives the detection signal of the pulse detection unit 1 or the comparison output (t> tz) from the comparator 4. An arithmetic unit for calculating an instantaneous value v (= ts / t; ts is a pulse cycle span).

The operation of the device of the present invention having such a configuration will be described with reference to the flowchart of FIG.

When the pulse signal P is detected by the pulse detector 1 when the timer 2 starts at the same time as the start of the measurement, the value t of the timer 2 at this time is given to the calculator 5 to calculate v = ts / t. Then, the instantaneous value v is calculated. Value t of timer 2 at this time
Is stored in the storage unit 3 as the value tz.

The pulse detection unit 1 constantly monitors the presence or absence of the pulse signal P, the pulse signal P is not detected, and the comparison result of the value t of the timer 2 and the value tz of the storage unit 3 performed by the comparison unit 4 is t> tz. During a period other than the above, the calculation unit 5 maintains the output v and does not operate.

When time tz elapses without detecting the input pulse P and t> tz in the comparison unit 4, the comparison unit outputs the calculation unit 5
Calculates the instantaneous value v from the value t of the timer 2 at this time and starts updating the previous instantaneous value v.

The above operation is repeated.

FIG. 3 is a time chart showing an actual operation example when the device of the present invention is used.

When the pulse signal P2 is given, the interval t1 between the pulse signal P1 and the pulse signal P2 is measured by the timer 2, and the calculation unit 5
The instantaneous value v1 is obtained at, and the storage unit 3 stores the value t1 as the value tz.

Further, when the pulse signal P2 is given, the comparison unit 4 starts the comparison operation between the value t and the value tz (= t1), and the calculation unit 5 maintains the instantaneous value v1 until the time tz elapses. When the next pulse signal P is not given even after the time tz elapses, that is, when the comparison output from the comparison unit 4 is performed, the calculation unit 5 uses the value t of the timer 2 at this time to calculate v = ts / t. Perform an operation.

The arithmetic unit 5 may be composed of an analog circuit or a microprocessor or the like.

Then, when the next pulse signal P3 is given, the calculation unit 5 outputs the correct instantaneous value v2 (= ts / t2) from the interval t2 between the pulse signal P2 and the pulse signal P3. On the other hand, the storage unit 3 stores the value t
Update and store z from value t1 to value t2.

Next, when the time tz (= t2) does not elapse, the pulse signal P4
Is given, the instantaneous value v3 (= ts / t3) is immediately calculated from the value t3 of the timer 2 at this time, and the value t3 is stored in the storage unit 3.
Stored as the value tz in.

After that, the same operation is repeated.

As can be seen from the time chart of FIG. 3, when the flow rate decreases, that is, when the cycle of the pulse signal P becomes longer,
Since the instantaneous value v gradually decreases due to the curves c1 and c2, 1
The delay of the output of the instantaneous value v can be minimized even through a secondary delay filter or the like. Even if the flow rate becomes 0%, it will gradually decrease from the previous instantaneous value, so the instantaneous value will not suddenly become 0%, the influence on peripheral devices will be small, and a state close to the actual flow rate will be output. can do.

In the above example, the period of the pulse signal is measured for each pulse, but when the pulse frequency is high, as shown in FIG. 4, the pulse intervals t1 and t2 of a plurality of shots n1 and n2 are set. The pulse period may be obtained by measuring and calculating the average values t1a (= t1 / n1) and t2a (= t2 / n2). In this case, when the pulse frequency becomes low, the pulse interval for each pulse is calculated.

<Effects of the Invention> As described above, in the pulse signal processing device of the present invention, the previous pulse cycle is stored in the storage means, and the current pulse signal is not input even if it exceeds the stored pulse cycle. In this case, since the instantaneous value is updated assuming that there is a pulse input at this point, even if the instantaneous value v is passed through a filter such as a first-order delay, the delay should be minimized to obtain a value close to the correct instantaneous value. Moreover, even if the pulse signal is interrupted, the output is gradually reduced and the peripheral device is not confused.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a pulse signal processing apparatus embodying the present invention, FIG. 2 is a flow chart showing the operation of the present invention apparatus, and FIGS. 3 (a), (b), and (c) are the present invention. FIG. 4 is a time chart showing an actual operation, FIG. 4 is a diagram for explaining a case of handling a high frequency pulse signal in the device of the present invention, FIGS. 5 (a), (b), (c) and FIG. 8A and 8B are time charts showing the operation of the conventional pulse signal processing device. 1 ... Pulse detection unit, 2 ... Timer, 3 ... Storage unit, 4
…… Comparison section, 5 …… Calculation section.

Claims (2)

[Claims] 1. A time counting means for receiving a pulse signal and counting the pulse period thereof, and for each time the pulse signal is given, a value stored at present is changed to a value of the previously measured pulse period and stored. Storing means, comparing means for comparing the count value of the time counting means with the value stored in the storing means, and when the pulse signal is given, the pulse cycle is calculated from the count value of the time counting means. When an instantaneous value is calculated and a signal indicating that the count value exceeds the value stored in the storage means before the pulse signal is given from the comparison means, the total value at that time is calculated. A pulse signal processing device, comprising: a calculating unit that calculates an instantaneous value of the pulse period from a numerical value. 2. The pulse signal processing device according to claim 1, wherein, as a period in which the pulse signal is given, the times possessed by a plurality of pulse signal groups are averaged to obtain a pulse period.