JPS5819537A - Abnormality detector for particle counter - Google Patents

Abstract

PURPOSE:To achieve accurate detection of abnormal counting and erroneous counting by determining abnormality from a difference or an error between acutual counts and the maximum or minimum value which was only memorized for respective time intervals beforehand. CONSTITUTION:Particles pulse signals from a line 13 are sent to shift registers 1 and 3. A signal for starting the counting is inputted to a line 14 while a signal for ending thereof into a line 15. On the other hand, a clock pulse generator circuit 11 generates pulses at specified time intervals set by dividing the counting time and actuates comparators 5 and 6 to compare counts of shift registers 1 and 2 and 3 and 4 and the register 2 memorizes the maximum value of the counts while the register 4 the minimum value. The clock pulses also reset the shift register 1 and 3 through a delay circuit 12. Based on the counts thus obtained, a subtraction circuit 7, a division circuit 8 and an abnormality discrimination circuit 9 are actuated after the end of the counting and an alarm 10 starts to work when any count exceeds the limit.

Description

[Detailed Description of the Invention] The present invention properly detects abnormal counts due to external noise and erroneous counts due to drift, etc. in a device that counts particles such as blood cells, and prevents errors from being mixed into measurement data. The present invention relates to an abnormality detection device capable of detecting abnormalities.

Conventionally, this is an effective means of detecting external noise.

When comparing the number of pulses before and after the particle detection pulse of a particle detection device divided into time intervals of 1 second, for example, the number of pulses before and after is almost constant, so local increases in the signal due to noise etc. A method has been used in which the difference between the number of pulses before and after each interval is taken, and when the difference exceeds a predetermined value, it is determined to be an abnormal state, and the abnormal state is detected by generating an abnormal signal.

However, while this type of conventional method is extremely effective in detecting sudden changes in conditions, it is not very effective in detecting sensitivity changes due to K, such as drift and gradual contamination of the detection area, and is not effective in detecting abnormalities. The drawback was that discovery was delayed.

Normally, to count particles such as blood cells floating in a liquid, 1
A narrow passageway that allows each particle to pass through is provided, and a liquid in which the particles are suspended is passed through the passageway. Particles are detected based on the difference in electrical impedance between the liquid and the particles, or the optical difference, and electrical There is a method of converting it into a signal and then counting each particle by passing only a predetermined particle signal using a threshold circuit that has a dark value voltage that is lower than the particle signal and higher than unnecessary noise and other particle signals. It is used.

In general, abnormal conditions during one count measurement are: - For example, when a noise signal larger than the threshold voltage level from an external source is mixed in. - When a passage in the detection area is clogged, when the passage in the detection area is contaminated. If the detection sensitivity decreases due to fluctuations in the means for transporting the particle suspension, or if the flow rate fluctuates due to fluctuations in the means for transporting the particle suspension, or due to insufficient stirring of the particle suspension.
For example, when measuring a sample that shows a specific distribution of particles.

In addition, biological particles such as blood cells can be destroyed by K, such as the pH and osmotic pressure of the liquid. When counting and measuring particles in the process of destruction, the number of detected pulses decreases over time and the true measured value cannot be obtained. In addition,
When measuring particles that make up a small proportion of blood cells, such as white blood cells, one red blood cell is destroyed with a hemolytic agent such as saponin, and only -0 blood cells remain for measurement, but the hemolysis of red blood cells is insufficient. In this case, a measurement error occurs in which the number of detected pulses decreases with time for K as well.

The present invention has been made in view of the above points, and includes a circuit that divides counting measurement time into predetermined time intervals, a circuit that separately stores only the maximum and minimum values of count values in each divided time, and By configuring an abnormality detection device from a circuit that generates an abnormality signal when the difference between and the minimum value and the ratio of the difference exceeds a predetermined limit value, it is possible to reliably detect abnormal counts and erroneous counts. The purpose of the present invention is to provide an abnormality detection device for a particle counting device that can be used in a particle counting device.

The configuration of the present invention will be explained below based on the drawings.

FIG. 1 is a systematic explanatory diagram showing one embodiment of the apparatus of the present invention, and FIGS. 2 to 4 are graphs showing the relationship between count values and time intervals in actual measurement examples.

In FIG. 1, L'13-4 are shift registers, and shift registers 1-2 and 3-4 are connected in series, respectively.

5 is a digital comparator connected to shift register 1-2, and 6 is a digital comparator connected to shift register 6.4. 7 is a subtraction circuit connected to the shift register 2-4; 8 is a division circuit connected to the shift register 2-4; 9 is an abnormality determination circuit connected to the subtraction circuit 7-division circuit 8; 10 The alarm device 11 connected to this abnormality judgment circuit 9 is connected to the digital comparator 5.6, and the lock pulse generation circuit 12 is connected to the clock pulse generation circuit 11 and the shift register 1.3. It is a circuit.

The particle pulse signals are sent by line 16 to two shift registers 1-2. On the other hand, the start signal for one counting measurement is line 1.
4, the termination signal is input to line 15. The clock pulse generating circuit 11 is controlled by the start signal and the end signal, and generates clock pulses at intervals of, for example, one second and sends them to one digital comparator 5-6. Digital comparator 5 compares the count values temporarily stored in shift registers 1 and 2.

When a value larger than the count value stored in the shift register 2 is counted in the shift register 1, the count value of the shift register 1 is transferred to the shift register 2. Similarly, the digital comparator 6 compares the count value temporarily stored in the shift register 4 with the count value of the shift register 6, and when the count value of the shift register 6 is smaller, transfers the count value to the shift register 4. let This operation takes place via a line 1117 which is connected from the digital comparator 5-6 to the shift register 1, 13.4, respectively. Further, the clock pulse of the clock pulse generating circuit 11 is turned into a reset signal with a time shift by the delay circuit 12, which resets the contents of the first shift register 1.6, and counts the number of pulses until the next clock signal. Immediately after the start of counting, the count values of shift registers 1-6 are transferred as they are to shift registers 2 and 4, and comparison is performed from the next clock pulse. Since the final count value stops in the middle of the clock, a fraction occurs and the above operation is prohibited.

As described above, the maximum count value between each clock pulse is temporarily stored in the shift register 2, and the minimum count value is temporarily stored in the shift register X14. After the measurement is completed, the subtraction circuit 7, the division circuit 8 and the abnormality determination circuit 9 are activated, and when a predetermined limit value is exceeded, the alarm device 10 is activated. When the particle density is relatively low, the absolute value of the number of particles counted is small, so it is necessary to look at the ratio to the total number of particles, and the division by 1 circuit is important. If it is counted, will some noise signal be hidden? Therefore, it is desirable to judge based on the difference.

Samples such as blood are usually subjected to single particle counting.

It is diluted to a relatively dilute soft tissue and converted to the original ratio after measurement. A commonly used dilution ratio is about 50,000 times for counting red blood cells, which results in a floating liquid containing about 5 million particles per raw blood/about 100 particles/w for Sobatake. For example, if we measure 250- of these and install a 1/50 frequency dividing circuit in the circuit leading to one counting circuit, - (100 pieces/s11 x 25Qss" x 1150
= 500, and you can get the effective figures up to the ten thousandth place of one original blood.

Therefore, the number of particle detection paths is approximately 25,000, which is 50 times larger, and the time required for one measurement is approximately 10 seconds.
The number of particle detection pulses per second is approximately 2,500.

Next, an actual measurement example will be explained. In FIGS. 2 to 4, the vertical axis shows the count value, and the horizontal axis shows the time interval. Figure 2 shows the normal count value for each interval buff 1/(1 second)K
The maximum value is 2535 and the minimum value is 251.
5, and the ratio of the maximum and minimum difference is about 0.8. However, as shown in Figure 3, if the counted values vary, the error can reach several degrees. Further, when a count value decreases over time as shown in FIG. 4, the maximum value is the initial value and the minimum value is the final value. In this case as well, an error of several fractions will occur. Therefore, the limit value of the abnormality judgment circuit 9 is set to 1.
Anomalies can be detected by setting the value to around -2. Furthermore, for particles with a high concentration, the ratio of error between and becomes small, so one absolute value itself becomes effective.

Therefore, in this case, the limit value of the abnormality determination circuit can be set as follows.

(Maximum value) - (Minimum value) ζ25 (l of actual count value 2500
When these values are exceeded, it is determined that there is an abnormality and the alarm device 10 is activated.

The above judgments can be made during the count measurement as necessary, and if an alarm is issued, the measurement is stopped midway, and the cause of the abnormality is confirmed, followed by prompting the count measurement again, or after the measurement is completed, printing or displaying At the same time, a method is used to mark the data at the same time.

As described above, the device of the present invention stores only the maximum and minimum values of the count values in each time interval, and one judgment is reliably made in order to judge an abnormality from the difference and error ratio, and the comparison It has an extremely simple circuit configuration, and has the effect of being able to accurately determine a single abnormality simply by incorporating it into a conventional particle counting device.

[Brief explanation of drawings]

FIG. 1 is a systematic explanatory diagram showing one embodiment of the present shouting device, and FIGS. 2 to 4 are graphs showing the relationship between the count values and time intervals V and O in actual measurement examples. L 2.5-4...Shift register, 5,6-...Digital comparator, 7...Subtraction circuit -8...-Division circuit. 9...Abnormality determination circuit-10-...Alarm device, 11...
・Clock pulse generation circuit, 1・2-・-Delay circuit-1
6-14, 15-1117...Line patent applicant Toa Medical Electronics Co., Ltd. Figure 2

Claims (1)

[Claims] 1. A circuit that divides the counting measurement time into predetermined time intervals, a circuit that separately stores only the maximum and minimum values of the count value in each divided time, and the difference between the maximum and minimum values,
and a circuit that generates an abnormality signal when the ratio of the difference exceeds a predetermined limit value.