JPS5817405B2 - signal measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sampling type signal measuring device, and more particularly to a signal measuring device that accurately detects an abnormal measurement state and outputs an alarm signal.

Generally, a sampling type signal measuring device measures the instantaneous value of an input signal at a certain period using a sampling signal.

Therefore, in this device, if there is fluctuation in the input signal, there is a problem in that the measured value changes rapidly every sampling period.

Therefore, in order to eliminate this kind of inconvenience, the input signal during the previous sampling period is held, and the deviation value is calculated by comparing this previous input signal with the input signal during the current sampling period. The deviation value is suppressed below a certain value, or the deviation value is smoothed by putting it into a smoothing circuit with a predetermined time constant to convert it into a signal with little change and output.

However, when using the above-described signal processing means, there are problems such as: (1) time delay in abnormality determination in response to excessive input, (2) time delay in abnormality determination in the case of missing measurements, and (2) error in determination in abnormal measurement conditions.

This point will be discussed in detail below.

■ Time delay in abnormality judgment due to excessive input...When an excessive input signal is input, this signal is suppressed by a smoothing circuit and gradually increases, so even though it is outside the measurement range and is in an abnormal measurement state, First, there is a drawback that it takes a long time until a signal indicating that the measurement range is outside appears on the output side of the smoothing circuit.

In other words, the smoothing circuit smoothes the input signal sampled at each sampling period and smooths the input signal level at each sampling period, so the output of the smoothing circuit is always suppressed, which results in an abnormal measurement state. The disadvantage is that it takes a very long time to make a decision.

■ Time delay in determining abnormality when measurement is missing...In sampling measurements, even if a measurement is missing several times in a row, if a signal within the measurement range is input before the measurement is missing, the smoothing circuit will be able to smooth the signal. As a result of this action, a signal appears at the output of the smoothing circuit.

Therefore, in detecting missing measurements, it takes a very long time, as mentioned above, until the signal level on the output side of the smoothing circuit falls below the measurement range and it is determined that there is an abnormal measurement state. There is.

■ Misjudgment of an abnormal measurement state: Even in the above-mentioned excessive input or missing measurement state, a signal will appear on the output side of the smoothing circuit due to the smoothing effect of the smoothing circuit, so it may take a long time until it is determined to be an abnormal measurement state. There is a problem in that the subsequent measurement system is determined to be normal.

The present invention has been made in view of the above circumstances, and
The signal input at each sampling period is subjected to judgment as it is without going through a smoothing circuit, and the signal is input for a predetermined number of sampling times.

The present invention provides a sampling type signal measuring device that determines whether a force signal is normal or not and determines whether it is an abnormal measurement, thereby accurately detecting an actual abnormal measurement.

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, 10 is a preamplifier circuit that amplifies the input signal using the timing signal (sampling signal) of the timing signal generation circuit 11, and 12 is a preamplifier circuit that determines whether the input signal is within the measurement range. Outputs a pulse signal to.

This is a preprocessing circuit.

This preprocessing is performed every time a timing signal is generated.

13 is a preprocessing circuit 12 for a predetermined number of timing signals.
This is a counting circuit that counts whether a pulse signal is output from the

The circuit 13 determines that an abnormal measurement is occurring when the difference between the pulse count and the number of timing signals within a predetermined time determined by the number of timing signals is equal to or greater than a predetermined value, and outputs a drive signal.

14 is an alarm circuit which receives the drive signal and generates an alarm signal.

15 is a signal conversion circuit for converting into an appropriate signal necessary for measurement, and 16 is a hold smoothing circuit.

Next, the operation of the signal measuring device configured as above will be explained.

First, the timing signal generation circuit 11 sends a timing signal (sampling signal) to the preamplifier circuit 10 at regular intervals.
, preprocessing circuit 12,.

The signal is applied to the count circuit 13, signal conversion circuit 15, and hold smoothing circuit 16.

When this timing signal is input, the preamplifier circuit 10 amplifies the input signal and supplies this amplified signal to the subsequent preprocessing circuit 12 and signal conversion circuit 15.

In this preprocessing circuit 12. In this case, it is determined whether the signal output from the preamplifier circuit 10 is within the measurement range, and if it is within the measurement range, it is determined that the measurement is normal, and a pulse signal is generated, which is sent to the counting circuit. Count at 13.

If the input signal is outside the measurement range or is missing, no signal will be generated from the preprocessing circuit 12.

This counting circuit 13 compares the number of times the timing signal is input in a predetermined period with the pulse count value output from the preprocessing circuit 12, and detects when the deviation (direction) is greater than a predetermined value, out of the measurement range or a missing measurement state. Therefore, it is determined that the measurement is abnormal due to outside the measurement range or missing measurement, and a drive signal is output.

Therefore, this drive signal causes the alarm circuit 14 to generate an alarm signal.

For example, in the case of missing measurements, it is actually outside the measurement range, so
If there is no pulse signal from the preprocessing circuit 12 even once when a timing signal is generated, it is determined that an abnormality is due to a missing measurement, but this number of times can be determined arbitrarily.

On the other hand, the signal received by the signal conversion circuit 15 is converted into an appropriate signal, held by the subsequent hold and smoothing circuit 16, and provided for measurement.

Therefore, in the sampling method signal measurement device of the present application,
The output of the preamplifier circuit 10 is directly input to the preprocessing circuit 12, and the deviation between the number of pulses output from this preprocessing circuit 12 and the number of samplings (directly determines whether the measurement is normal or abnormal) Therefore, the decision time is much shorter than in the past, and the shorter the decision time, the fewer incorrect decisions will be made.

Unlike conventional methods, abnormal measurement conditions such as input signal levels outside the measurement range or continuous missing measurements are not judged as normal, but normal measurements with large input signals are judged as abnormal measurements. There will be no more.

In the above embodiment, the input signal is amplified by the preamplifier circuit 10 at each sampling period, but this amplification may be performed continuously and only subsequent processing may be sampled.

It is also possible to process the input signal directly without using a preamplifier circuit.

Further, as an example of application of this device, it is effective in the following cases.

In computers that read analog signals, there are times when the analog signal cannot be read, resulting in a so-called excessive input.

In such a case, it is also possible to issue a warning by determining how many times the measurement has been missed within a certain period of time.

As described in detail above, according to the present invention, the sampled value of the input signal is taken in as it is, it is determined whether the signal is within the measurement range, and the number of times the signal is within the measurement range for a predetermined number of samplings is determined. Since the presence or absence of an abnormal measurement is determined based on whether the measurement is being performed, abnormal measurement conditions such as signals outside the measurement range or missing measurement conditions can be quickly and accurately detected. Since it is possible to detect abnormal measurements relatively quickly, the input signal can be smoothed and used as a stable signal for measurement.

[Brief explanation of the drawing]

The figure is a block diagram showing an embodiment of a signal measuring device according to the present invention. 10... Preamplifier circuit, 11... Timing signal generation circuit, 12... Preprocessing circuit, 1
3...Count circuit, 14...Alarm circuit, 15...Signal conversion circuit, 16...
Hold smoothing circuit.

Claims (1)

[Claims] 1. In a signal measuring device that smoothes and measures a human signal supplied for each sampling signal using a smoothing circuit, the level of the input signal supplied for each sampling signal to the input side of the smoothing circuit is within the measurement range. A preprocessing circuit that outputs a pulse signal only when a count circuit that outputs a drive signal when the deviation [direction] is greater than a predetermined value;
A signal measuring device comprising: an alarm circuit that outputs an alarm signal using a drive signal of the count circuit.