JPS59202031A - Measuring apparatus - Google Patents

Abstract

PURPOSE:To reduce errors in the measurement with a correction in a quick response to changes in the temperature made possible by outputting a timing signal each time such a change is sensed in the measuring such items as the weight, length and flow rate of an object to update the correction value. CONSTITUTION:When an object to be measured is placed on a measuring tray 11, a weighing signal from a weighing device 12 undergoes a subtraction by a hold value of a zero-point hold circuit 14 with a subtractor 15 via an A/D converter 13 to perform a zero-point correction and the results are multiplied by a multiplication factor held in a sensitivity hold circuit 19 with a multiplier 20 to correct the sensitivity. When a temperature sensor 22 detects a specified temperature change during the weighing operation, a timing signal TM1 is outputted to the zero-point hold circuit 14 from a timing generation circuit 23. Then, when a reference weight 17 is placed on the measuring tray 11, a timing signal TM2 is outputted to a reference weight driver 21 and a divider 18 from the timing generation circuit 23 to perform a correction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a measuring device for measuring various quantities such as weight, length, flow rate, etc. of an article.

BACKGROUND OF THE INVENTION Measuring devices, such as weight measuring devices, generally use a correction device to correct the zero point or sensitivity of a measured value of the weight of an object to obtain a measured value with few errors.

Since this correction point changes, conventional measuring devices update and store correction points such as the zero point and sensitivity every predetermined time period or every predetermined number of measurements.

However, the biggest cause of fluctuations in zero point, sensitivity, etc. is drift due to temperature changes in electrical elements, so even if the correction points are updated at fixed intervals or every number of measurements, temperature changes This method has the disadvantage that the measurement error becomes large when it occurs in a short period of time.

In order to cope with such temperature changes, conventionally, as shown in FIG.
Temperature sensor 2 is stored in memory and temperature sensor 2 is provided.
An address signal corresponding to the temperature change detected by is sent to the memory circuit IJL%1b, and with this address signal, the zero point and sensitivity correction values in the memory circuit 1as1b are read out, and corrections are made based on the correction values read out in this way. circuit 3
．． In No. 4, a method of correcting the weighing signal of the measuring instrument 5 was carried out.

However, in this method, if the correction device stored in the storage circuit 1as1b is changed, the temperature test is performed again to detect the correction value corresponding to the temperature change. It was very complicated because it had to be stored again in the memory circuit 1a11b.

The object of the invention is to provide a measuring device which overcomes the above-mentioned drawbacks.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 2 is a block diagram showing an embodiment in which the present invention is applied to a weight measuring device.

In the figure, 11 is a weighing pan, 12 is a weighing device that outputs a weighing signal corresponding to the weight of the object to be weighed supplied to the weighing pan 11, 13 is an A/D converter that converts the weighing signal into a digital value, and 14 is the A/D when the weighing pan 11 is empty.
Zero point hold circuit for holding the output of the converter 13, 1
5 is a subtractor for subtracting the value held in the zero point hold circuit 14 from the output of the A/D converter 13 when the object to be weighed is placed on the weighing pan 11; and 16 is a subtracter in which the true weight of the reference weight 17 is set. 18 is a reference setting device 6, 16 degrees, l semi-heavy weight, 111 is a divider that divides by the output value of the subtractor 15 when the semi-weight 17 is placed on it, 19 is a division Vessel 1
8 is a sensitivity hold circuit that holds the output value (multiplication rate); 20 is a subtractor 15 when the object to be weighed is placed on the weighing pan 11;
A multiplier that multiplies the output value by the multiplication factor held in the sensitivity hold circuit 19 and outputs the result; 21 is a reference weight 17;
a reference weight driving device 22 for driving and placing the reference weight on the weighing pan 11;
23 is a temperature sensor that detects the environmental temperature and outputs a signal corresponding to the temperature; 23 receives a temperature signal from the temperature sensor 22, and sends a timing signal TMl (weighing pan 11 ), T
This is a timing generation circuit that outputs M2 (when the reference weight 17 is placed on the weighing pan 11), TM to the zero point hold circuit 14, and 'f'M to the reference weight drive device 21 and the divider 18. These two timing signals TMl, T
M, outputs force Z, with a delay.

Next, the operation of the above embodiment will be explained.

First, the output value of the A/Di converter 13 with the weighing pan 11 empty is held in the zero point hold circuit 14. Next, the reference weight drive device 21 places the reference weight 17 on the empty weighing pan 11, and the subtracter 15 subtracts the value held in the zero point hold circuit 14 from the output value of the A/D converter 13 at this time. The output value (that is, the measured value of the reference weight 17) is input to the divider 18, the reference weight output from the reference amount setter 16 is divided by the output value of the subtracter 15, and the division result is sent to the sensitivity hold circuit. Let 19 hold. After first setting the zero point and g degrees in this way, the normal weighing operation of the object to be weighed is performed.

That is, when an object to be weighed is placed on the weighing pan 11, the weighing signal from the weighing device 12 is sent to the subtracter 15 via the A/D converter 13.
The value is subtracted by the hold value of the zero point hold circuit 14 for zero point correction, and further multiplied by the multiplication factor held in the sensitivity hold circuit 19 by the multiplier 20 to compensate for the sensitivity and output. While this metering operation continues, the temperature sensor 22 monitors the temperature change, and the timing signal is not output from the timing generation circuit 23 while the temperature does not change by a predetermined temperature (for example, 1°C), so the zero point hold circuit 14 And the value held in the sensitivity hold circuit 19 will change, and the same correction value will be positive again! ll be approached. Then, when the temperature sensor 22 detects a change in the temperature of the foot, the timing generation circuit 23 first outputs the timing signal No. 5-TM to the zero point hold circuit 14, and the weighing pan 11
When the weight is empty, the 8"3 weight of the A/D converter 13 is held in place of the previous hold weight. Next, when the base weight 17 is placed on the weighing pan 11, timing is generated. Timing signal TM2 or reference weight driver 2 from circuit 23
1 and output to the divider 18. This/kome, 11. The semi-weight drive device-21 operates and the reference weight 17 force scale t゛1
The force value is input to the divider 18 and divided by L.
This new multiplication factor is then changed to the bold fa2 of m:J, and is old to the degree hold turn 19.

And then there's the weighing operation.・The correction is then continued using this newly held zero point and sensitivity. Similarly, each time a predetermined temperature change occurs, the zero point hold value and the sensitivity hold value are automatically updated, and correction is performed based thereon.

FIG. 3 is a block diagram showing another embodiment of the present invention. This embodiment differs from the circuit shown in FIG. 2 in that the sensitivity can be held by placing the reference weight on the weighing pan 11 with the object to be weighed. A measured value hold circuit 24 holds the output value of the MB unit 15 when the object is weighed, and a subtracter 15 when the reference weight 17 is further placed on the weighing pan 11 together with the object to be measured.
The only difference is that a subtracter 25 is added which subtracts the hold value of the defined value hold circuit 24 from the output value of and outputs the result to the divider 18.

That is, the measured value hold circuit 24 holds the output value of the subtractor 15 when the object to be weighed is placed on the weighing pan 11, and then holds the output value of the subtracter 15 when the reference weight 17 is further added. From the output, the hold value of this measured value hold circuit 240 is calculated (+11 is input to the divider 18 and the multiplication rate is held in the sensitivity hold circuit 19,
Thereafter, updating the zero point and sensitivity according to temperature changes is similar to the embodiment shown in FIG. 2.

In addition, although the above embodiment describes an example in which the present invention is applied to a weight measuring device, the invention is not limited to just a weight measuring device, and may also be applied to a device for measuring length or flow rate. , this j can be applied.

As is clear from the above explanation, in the measuring device of the present invention,
The system detects temperature changes and outputs a timing signal when the temperature changes to update the correction value.This allows correction to be made quickly in response to temperature changes, which are the largest cause of fluctuations in measured values, and reduces measurement errors. This makes it possible to perform measurements with fewer errors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional one-lid measuring device.
FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a block diagram showing another embodiment of the invention. ia, lb... Memory circuit, 11... Weighing pan, 12... Measuring instrument, 14... Zero point hold circuit, 15... 1. Subtractor, 16...
...Reference amount setting device, 17...Reference weight, 18.
...divider, 19...sensitivity hold circuit,
20... Multiplier, 21... Reference weight drive device, 22... Temperature sensor, 23...
・Timing generation circuit. Patent Applicant Anritsu Electric Co., Ltd. Agent Patent Attorney Makoto Hayakawa

Claims (1)

[Claims] In a measuring device that corrects and outputs a measurement signal that is frequently output from a measuring device based on a correction value stored in a correction device; A measuring device characterized in that it is updated when a timing signal is output.