JPH08178737A - Load cell type balance - Google Patents

Abstract

PURPOSE: To obtain a load cell type balance in which the reliability can be prevented from lowering when a constitution for compensating the measurement on the load cell side and transmitting a compensated measurement to an indicator unit is employed. CONSTITUTION: A measurement data is compensated based on the characteristics stored at a characteristics memory section 5 on the load cell unit 1a side before being delivered to an indicator unit 3. The main control section 8 of the indicator unit 3 reads out the content of the characteristics memory section 5 periodically and collates the content thus read out with the content at a main memory section 12. The main control section 8 determines that the content stored in the characteristics memory section 5 is correct and makes a decision that a trouble has occurred upon detection of mismatch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load cell type balance.

[0002]

2. Description of the Related Art A load cell unit used in a load conversion unit of a load cell type balance is equipped with a load cell and an electronic circuit, and this electronic circuit digitally outputs a signal whose load has been converted by the load cell. Is configured.

The output of the load cell unit is taken into an indicator, subjected to internal processing such as span and temperature correction, and displayed as a weight value.

[0004]

In contrast to the internal processing on the side of the indicator, on the side of the load cell unit, a storage element capable of storing characteristic values (digital span and temperature correction data) and load conversion by the load cell. It is conceivable to provide a microcomputer that corrects the signal as it is based on the contents stored in the storage element, and to digitally output the signal for which various corrections have been completed as a weight value from the load cell unit.

In this case, there is an advantage that the load cell unit alone can be adjusted without connecting the load cell unit and the indicator. However, if a partial abnormality of the memory element occurs during use of the scale and the abnormality that changes the stored characteristic value of this memory element occurs, it is detected even if the indicator display is monitored. Difficult to do.

It is an object of the present invention to provide a load cell type balance in which an abnormality occurring in a load cell unit can be easily detected on the indicator side.

[0007]

A load cell type balance according to claim 1, wherein a load is supported by the load cell, and an output signal of the load cell is subjected to signal processing based on a characteristic written in a characteristic storage section and output. And an indicator unit that is connected to the load cell unit via a communication line and displays the measured weight of the load cell unit, and communicates between the load cell unit and the indicator unit via a communication line to enable communication on the load cell unit side. It is characterized in that it is configured to collate whether the content of the characteristic storage unit is a specified content.

According to a fifth aspect of the load cell type scale, the indicator unit or the load cell unit communicates between the load cell unit and the indicator unit via a communication line so that the contents of the characteristic storage section on the side of the load cell unit are If an abnormality is detected by checking whether it is the specified content,
The indicator unit or the load cell unit is configured to rewrite the contents of the characteristic storage unit on the side of the load cell unit.

[0009]

According to the first aspect of the present invention, the load cell unit compensates for the characteristic based on the characteristic written in the characteristic storage section, and then the signal is sent to the indicator unit via the communication line. The stored contents of the characteristic storage unit are collated with the reference contents on the side of the indicator unit to determine the occurrence of a failure in the stored contents of the characteristic storage unit.

According to the structure of claim 5, the abnormality is detected, and the indicator unit or the load cell unit rewrites the contents of the characteristic storage unit.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the load cell type balance of the present invention will be described below with reference to FIG. In this embodiment, four load cell units 1a, 1b, 1c and 1d support the measured load. The load cell units 1a to 1d are connected to the indicator unit 3 via the communication line 2. The load cell units 1a to 1d and the indicator unit 3 are configured as follows.

Since all of the load cell units 1a to 1d are the same, the load cell unit 1a will be described here as an example. As shown in FIG. 1, in addition to the load cell 4, a characteristic storage unit 5, a signal processing unit 6, a communication control unit 7, and the like are housed in the load cell unit 1a. The signal processing unit 6 digitally converts the analog output of the load cell 4, reads the temperature correction value from the temperature correction function stored in the characteristic storage unit 5 based on the temperature information in the vicinity of the load cell 4, and digitally converts the load cell. The output of No. 4 is corrected by this temperature correction value and output.

In addition to the temperature characteristics of the zero point, the characteristics storage unit 5 has temperature characteristics of the span, zero offset value, span coefficient, linear characteristics, creep characteristics, digital filter characteristics, and operating conditions of the signal processing unit 6. Is written,
In the signal processing unit 6, based on the contents of the characteristic storage unit 5, span correction, zero offset, linear correction, creep correction,
Unnecessary signal removal is also performed.

It should be noted that the load cell units 1a to 1d are assigned different identification numbers in advance, and the main control unit 8 of the indicator unit 3 via the communication control unit 9 and the communication line 2 each load cell unit 1a to 1d. Requesting the weight value data by sequentially specifying the identification numbers of the load cell units 1a to 1d via the communication line 2 and calculating the sum value of the weight values collected from the load cell units 1a to 1d to display 10 and external input / output. Output to the unit 11. This identification number is also written in the characteristic storage unit 5.

The main control unit 8 of the indicator unit 3 reads the data of each load cell unit 1a to 1d as described above and reads all the data written in the characteristic storage unit 5 of each load cell unit 1a to 1d. The communication control unit 9 and the communication line 2, the communication control unit 7, the signal processing unit 6
Instruct regularly via.

The characteristic data of each of the load cell units 1a to 1d, which are periodically read out to the indicator unit 3 side, are collated with the characteristic data of each of the load cell units 1a to 1d written in the main memory 12 in advance. .

This load cell type scale is separately adjusted for each of the load cell units 1a to 1d and divided into indicator units. The indicator unit 3 and each of the load cell units 1a to 1d are connected by a communication line 2 to operate. In doing so, firstly, the main control unit 8 causes the temperature characteristics of the zero point of each load cell unit 1a to 1d, the temperature characteristics of the span, the zero offset value, the span coefficient, the linear characteristic, the creep characteristic, and the digital characteristic via the communication line 2. The filter characteristics and the operating conditions of the signal processing unit 6 are written in the main storage unit 12.

With this configuration, the accuracy of compensation is improved as compared with the case where the load cell units 1a to 1d are compensated on the side of the indicator unit 3, and moreover, the contents of the characteristic storage section 5 on the side of each load cell unit. Is checked by the main control unit 8 of the indicator unit to detect whether or not the content of the characteristic storage unit 5 is correct, and when it is determined that the content of the characteristic storage unit 5 is incorrect, the main control unit 8 By stopping the output to the display unit 10 and the external input / output unit 11, the weight value with reduced reliability is not output.

Further, by transmitting the reference value of the characteristic data written in the main memory unit 12 to a necessary one of the load cell units 1a to 1d and updating the contents of the characteristic memory unit 5, the load cell is updated. You can try to recover from a unit failure.

In the above-described embodiment, the main control unit 8 is configured to automatically collate the contents of the characteristic storage unit 5 at regular intervals, but when the external instruction is given to the main control unit 8, the collation is performed. It can also be configured to perform an action.

In the above embodiment, the indicator unit 3 collates the contents of the characteristic storage unit 5 of each of the load cell units 1a to 1d. If the contents of the characteristic storage unit 5 are abnormal, the indicator unit 3 stores an abnormal characteristic memory. Although the unit 5 is configured to be updated to the reference content, the load cell units 1a to 1d may be configured to read and verify the reference content registered in the indicator unit 3 via the communication line 2. In this case, the abnormality in the contents of the characteristic storage unit 5 is detected and the abnormality is notified to the indicator unit 3 via the communication line 2.

Further, when the load cell units 1a to 1d perform collation and determine that the contents of their own characteristic storage unit 5 are abnormal, the contents of each load cell unit based on their own abnormal characteristics storage unit 5 are used as the reference contents. Can also be configured to update.

Each load cell unit 1a of the above embodiment
The signal processing units 6 to 1d only compensate the output of the load cell 4 based on the contents of the characteristic storage unit 5. However, the characteristic storage unit 5 detects the temperature abnormality of the use atmosphere of the load cell and the calibration expiration. By calibrating so as to rewrite the contents of, the abnormality can be detected when the main control unit 8 on the side of the indicator unit 3 carries out the collation.

[0024]

According to the first aspect of the invention, the output signal of the load cell is signal-processed based on the characteristics written in the characteristic storage unit and transmitted to the indicator unit via the communication line for output. The load cell unit can be adjusted independently without connecting to the unit. Moreover,
The display of the indicator unit is monitored because it is configured to communicate between the load cell unit and the indicator unit via a communication line to check whether the contents of the characteristic storage section on the load cell unit side are the specified contents. Therefore, it is possible to easily confirm the occurrence of abnormality and expect improvement in reliability.

According to a fifth aspect of the present invention, in the first aspect, the indicator unit or the load cell unit communicates between the load cell unit and the indicator unit via a communication line, and the characteristic storage unit on the side of the load cell unit. If the indicator unit or the load cell unit rewrites the contents of the characteristic storage section on the load cell unit side when an abnormality is detected, it is possible to recover from the abnormality of the load cell unit. You can try, and you can expect further improvement in reliability.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a load cell type balance of the present invention.

[Explanation of symbols]

 1a to 1d load cell unit 2 communication line 3 indicator unit 4 load cell 5 characteristic storage unit 6 signal processing unit 8 main control unit 12 main storage unit

Claims (5)

[Claims] 1. A load cell unit, which supports a measured load with a load cell, performs signal processing based on the characteristics of an output signal of the load cell written in a characteristic storage unit, and outputs the load cell unit, which is connected to the load cell unit via a communication line. And an indicator unit that displays the measured weight of the load cell unit, and communicates between the load cell unit and the indicator unit via a communication line to check whether the contents of the characteristic storage unit on the load cell unit side are the specified contents. A load cell type scale configured as described above. 2. The load cell type balance according to claim 1, wherein the indicator unit periodically reads and verifies the contents of the characteristic storage section on the load cell unit side via a communication line. 3. The load cell type balance according to claim 1, wherein the load cell unit periodically reads and compares the reference content of the indicator unit side via a communication line. 4. The characteristic storage section on the side of the load cell unit includes a zero point temperature characteristic, a span temperature characteristic, a zero offset value, a span coefficient, a linear characteristic, a creep characteristic, an identification number, a digital filter characteristic, and a signal processing section. The load cell type balance according to claim 1, wherein at least one characteristic of operating conditions is written. 5. The indicator unit or the load cell unit communicates between the load cell unit and the indicator unit via a communication line to check whether the content of the characteristic storage unit on the side of the load cell unit is a prescribed content. The load cell type balance according to claim 1, wherein when an abnormality is detected, the indicator unit or the load cell unit rewrites the contents of the characteristic storage unit on the side of the load cell unit.