JPH0795022B2 - Material testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention calibrates measured values used when calibrating the obtained data by performing a material test using a detection device that detects a load and a displacement amount. Regarding the device.

[Prior Art] In the material testing machine, the load signal from the load detector (load cell) is amplified by the load amplifier, A / D converted by the A / D converter, and the load value is calculated by the data processing device. There is. In general, the load amplifier is provided with several load measurement magnifications (ranges) to properly perform load measurement.

In such a material testing machine, for example, when an actual load is applied to a load cell to perform load calibration with a load amplifier, normally, measurement is performed with only one calibration magnification using a calibration variable resistor 1 as shown in FIG. It has been calibrated once before. Even if the measurement range 2 is switched and another measurement magnification is set, the calibration is performed with the same amplification factor. However, in actuality, in order to correct the linearity characteristic peculiar to the load cell, it was necessary to provide a calibration variable resistor 1 for each measurement range for adjustment as shown in FIG. In the characteristic curve of the load cell shown in Fig. 4, this is calibrated in the x1 range, and when the x2 range is used to apply a full-scale actual load of x2, the output is 49 x 2 = 98, and the load cell is This is because the correction of +2 is necessary to maintain the linearity of.

[Problems to be Solved by the Invention] However, in the above-described calibration, there are problems that the circuit becomes complicated because the calibration variable resistor and the like are provided and that the calibration accuracy is reduced. Moreover,
When a plurality of load cells are used in a switching manner for one load amplifier, the linearity characteristics of each load cell are different. Therefore, in the calibration using the variable resistance for calibration, the appropriate calibration for each load cell is required. There was also a problem that it could not be obtained.

Therefore, the present invention improves calibration accuracy by eliminating the conventional adjustment operation performed using a calibration variable resistor or the like, and is measured by each detection device even when a plurality of detection devices such as load cells are used. An object is to provide a material testing machine capable of calibrating measured values.

[Means for Solving Problems] The present invention adopts the following configuration in order to solve the above problems.

That is, the present invention, in a material testing machine for detecting the amount of change such as load or elongation by switchingly using a plurality of detection devices, stores the type of the detection device and each measurement range of each detection device. Storage means for storing each detection device and a calibration coefficient corresponding to each measurement range of the detection device, means for instructing the type of the detection device used for measurement, and means for instructing the used measurement range, and these instructing means The calibration coefficient corresponding to the type of the detection device and each measurement range of the detection device is called by a command from the device, and the output signal from the detection device is multiplied by the calibration coefficient to calibrate the measurement value. It is characterized by

[Operation] Even when a plurality of detection devices are used, the calibration coefficient is stored for each measurement range of each detection device, and the detection signal from the detection device used for measurement is multiplied by the predetermined calibration coefficient to calculate. Since it is processed, an appropriate calibration is performed for each measured value simply by instructing the microcomputer of the measuring range of the device used.

[Examples] The present invention will be described below with reference to Examples.

FIG. 1 is a block diagram showing a calibration device of the present invention, in which a load signal from a load cell 5 (n pieces from No. 1 to No. n are used in a switching manner) is amplified by a weight amplifier 6. It is input to the / D converter 7. A / D converted load signal X here
Is input to the CPU 8 and processed. The load value Xout calculated by the CPU 8 is output to the recorder 13 and recorded by the recorder 13.

The memory 10 of the CPU8 stores the type of load cell used from No. 1 to No. n, the measurement range for each load cell, and the calibration coefficient corresponding to the measurement range.
A necessary calibration coefficient is read out when calculating

The calculation process is performed to calculate the load value Xout as Xout = Jx · X, where Jx is the calibration coefficient for the A / D converted value X of the load signal.

Here, the calibration coefficient Jx is set so that Xout becomes the full-scale value f when the full-scale actual load is applied in the maximum sensitivity measurement range of the load amplifier 7, for example, × 100. If the set full-scale load is applied to the load cell in a range other than this range, Xout will show f + α due to the influence of the linearity of the load cell. That is, an error of α occurs with respect to full scale. Therefore, the calibration factor in this range is Jx
・ If f / (f + α) is set, Xout will be the full-scale value f. The calibration coefficient thus obtained is stored in the memory 10 for each measurement range of each load cell as a coefficient corresponding to the measurement range. is there. Table 1 shows the storage state in the memory 10 in the embodiment.

The memory 10 of the CPU 8 stores the calibration coefficient for each measurement range of each load cell as described above. To read the calibration coefficient necessary for calibration, the load cell type instructing means 11 which indicates the type of the load cell 5 is read. And the measurement range instructing means 12 for instructing the measurement range in the load detector 6 are used. These indicating means 11, 12
For example, a changeover switch or the like can be used.

In this way, when the material test is performed, the load cell to be used and its measurement range are discriminated by the CPU 8, the necessary calibration coefficient is read out, and the calibration is performed for each measured load value.

Although the output calibration of the load amplifier of the load cell of the material testing machine has been described in the above embodiment, the output calibration of the extensometer and its extension amplifier can be carried out using the same configuration.

[Effects of the Invention] As is clear from the above description, according to the present invention, the measurement value can be calibrated without the adjustment operation performed using the calibration variable resistor or the like, so that the accuracy can be increased, and moreover, a plurality of Provided is a material testing machine capable of performing appropriate and reliable calibration for each measuring range of an amplifier for each of the detecting devices even when the detecting devices are switched and used.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIGS. 2 to 4 are diagrams for explaining conventional calibration. 5 …… Load cell, 6 …… Weight amplifier 7 …… A / D converter, 8 …… CPU 10 …… Memory, 11 …… Load cell type indicating means 12 …… Measuring range indicating means

Claims (1)

[Claims] 1. A material testing machine for detecting a change amount such as load or elongation by using a plurality of detecting devices in a switching manner, storing the type of the detecting device and each measuring range of each detecting device, Storage means for storing each detection device and a calibration coefficient corresponding to each measurement range of the detection device, means for instructing the type of the detection device used for measurement, and means for instructing the measurement range used, and from these instructing means By calling the calibration coefficient corresponding to the type of the detection device and each measurement range of the detection device, and multiplying the calibration coefficient with the output signal from the detection device to calibrate the measurement value. Material testing machine characterized by.