JPS5942247B2 - Weighing method using a microcomputer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a weighing method using a microcomputer.

The present invention provides a new weighing method that uses a microcomputer to precisely and quickly perform the selection and combination of weights, addition/subtraction operations, calculations of added weights, and display of weight values in automatic balances, automatic platform scales, etc. This is what we provide.

The first invention will be described in detail below with reference to FIGS. 1 to 3.

In FIG. 1, a weighing pan 3 is attached to one end of a weighing rod 2 supported on a fulcrum 1, and a plurality of types of weights 5 are attached to the other end.
The mounting tables 4 on which are placed are each fixed.

A weighing transducer 6, a braking damper 7, and a vertical limit stopper 8 are arranged on the mounting table 4 side of the weighing rod 2.

The transducer 6 may be any known transducer, but in this example, the transducer 6 is a transducer for unbalance detection in which a magnetic core suspended from the weighing rod 2 is freely fitted inside the transducer and is excited by an appropriate DC power source. It consists of a differential transformer 9 and a coil 10 in which a permanent magnet fixed to the end of the weighing rod 2 is fitted in a freely movable manner, and returns to the output coil 10 of the transformer 9 to generate a restoring force. A transducer is used that maintains the balanced state of the weighing rod 2 and uses a feedback current as a measurement output signal.

The output of this transducer 6 is sent to an eight-way converter 12 via an amplifier 11, where it is converted into a digital signal and then sent to a microcomputer (hereinafter referred to as CPU).
14.

After a predetermined operation, which will be described later, is performed in the CPU 14, a weight addition/removal signal is output from the CPU 4, and the weight addition/removal device 13 is controlled based on this signal.

This weight adjustment/removal device 13 may also be a known device, for example, a device that directly operates operating levers provided corresponding to each of the weights 5 using an electromagnetic mechanism.

In this example, the weighing range is 20 (k7, i.e. up to 20
It is designed to be able to weigh up to ←→,
10-1 maj→, 2←φ, 1.5(k→, 1- and 50
Six types of weights each weighing 0 (g) are provided.

In addition to the above, input/output devices for the CPU 14 include a date setter 15, product type setting device 16, weight setting device 17, print command button 18, clear command button 19, counter reset button 20, product type weight indicator 23, and counter display. A device 24 and a printer 25 are provided.

Although the transducer 6 is generally capable of accurate measurement within a certain range, it is undeniable that the error increases beyond the above range.

Figure 2 shows the custom output of the transducer 6.
Precise measurement is possible in the range of weight ±500 (g) that has linearity in this graph.

The error is relatively large in a region having non-linear characteristics exceeding weight ±500%.

Therefore, the precision measurement range is up to ±500 (g), and the range exceeding this, that is, from ±500 (g) to ±2← cut, is the weight addition/removal discrimination range, and at the time of final weighing after the weight addition/removal operation by the CPU 14 described below. , the output of the transducer 6 must be within the precision measurement range.

FIG. 3 shows an execution flowchart of the CPU 14.

If the total weight of the weights 5 placed on the mounting table 4 is now W, this weight W is stored in the register A.

First, the data value (D) from the A-D converter 12 is read in response to a start signal, the content W stored in the register and the data value (D) are added, and the sum (T) is added to the product weight display 21. to be displayed.

Next, compare the data value (])) and (2000) (corresponding to 2-), and if IDI>2000, read the data value (RW=2000) from the storage device to the register, In the case of , the data value (D) and (1
If IDI≦1500, further comparisons are made with (1000) and (500) in sequence.

+ DI>1500, IDI>I OOO or ID
If I>500, the data value (RW=
150011000 or 500) into the register.

If IDI≦500, the system returns to the string and takes in a more accurate data value (D) as the swinging of the scale rod 2 attenuates, and adds it to the stored content W of the register N to obtain the weighing value (T). indicate.

If IDI>500.1000.1500 or 2000, the polarity of the data value (D) means that the object to be weighed on the weighing pan 3 is heavier than the weight 5, and the end of the transducer 6 of the weighing rod 2 is upward. (pole f'1
E (-4-)) or the opposite (polarity (→)).

When the polarity is (a), the contents W of register A and the register contents (RW) are added (W+RW=Wa), and when the polarity is (a), they are subtracted (WRW=Ws), and the contents of register A are stored. Contents from W to (Wa) or (Ws
).

Then, this new stored content (Wa) or (Ws) is converted into a weight addition/removal signal and output to the weight addition/removal device 13.

The addition/subtraction device 13 uses this signal to calculate the total weight of the weight 5 placed on the mounting table 4 from W to (Wa) or (Ws).
Addition/subtraction operations are performed so that .

It takes a certain amount of time (for example, about 0.3 seconds) to add or subtract the weight 5, so after performing the clock operation in the CPU during this time, the process returns to reading the data value (D) again.
The same operation as above is performed.

In the above, for convenience of explanation, 1000.1500.20
Although the value 00 was used, since the transducer 6 has non-linearity in the region exceeding ±500g as mentioned above,
In reality, when the difference between the weight of the object to be weighed and the content W stored in register A is 2 ([stock]), the output of transducer 6 is smaller than the corresponding value 2000 (Dl), 1.5-11 (output (D2) even in case of k cut) <150
0, output (D3) <loo.

becomes.

Moreover, when the output is larger than (Dl), the A-D converter 12 overflows.

By the way, in the above execution program, the determination at each stage of the magnitude of the data value (D) and the set value (Dn) is performed in the first step.
Is the th overflow or not? The second one is l
Is D l > D2 or IDI≦D2? And so on.

Furthermore, reading of the data value (D) is performed only when IDI is less than Dt, and when l D l > Dl, the content W of register A and the data value (D) are added and summed (T).
is not displayed.

Next, the execution of the program and the combination of the weights 5 will be specifically explained.

Now, what is the weight of the object being weighed on the weighing pan 3? 5.
82 (k7), and it is assumed that no weight 5 is added on the mounting table 4.

In the first time, the output of the transducer 6 is (Dl
), so a weight of 2- is immediately added.

Similarly, weights 5 are placed on the mounting table 4 using the weight combinations shown in Table 1.

Then, in the eighth time, 1.5 (k!9) weights are added, which is determined as l D l >D2.

In the 9th time, D=320, 15500+320=
The calculation of 15820 is performed, and 15.820 (k→) is displayed on the product weight display 21.

If the time required for adding and subtracting the weight 5 is 0.3 (S) each, the time required during this period will be approximately 2.4 (S).

Note that in the eighth execution loop as well, a weight value close to the above-mentioned number is displayed.

After weighing, if the print command button 18 is pressed, the weighed value is printed on the printer 25 along with the preset date, product type, etc.

Further, if the clear command button 19 is pressed, the product weight display on the display 21 disappears.

It should be noted that if the object to be weighed on the weighing pan 3 is removed, the same operation as above is performed, the contents stored in the register A become zero, and the weight 5 is completely removed from the mounting table 4.

Since the apparatus shown in FIG. 1 is equipped with a setting device 17, the weight to be measured can be set in advance.

This is convenient for weighing powders, granules, etc.

When objects to be weighed are placed one after another on the weighing pan 3, their weights are successively displayed on the product type weight display 21 by the above-described operation.

In addition, the difference between the set amount and the weight is calculated by the calculation device in the CPUI J and successively displayed on the deviation indicator 22.
When the deviation becomes zero, the object to be weighed is placed on the weighing pan 3 as desired.

Furthermore, a cumulative total display 23 is provided for a certain series of measurements.

The cumulative total display 23 displays the total weight of each product for each of the plurality of weighings that are sequentially performed.

Further, the number of times this series of measurements is performed is counted by the Karasifu and displayed on the counter display 24.

When a series of measurements is completed and the count reset button 20 is pressed, the cumulative total display 23 and counter display 24 are reset, and preparation for the next measurement is made.

Furthermore, the transducer 6 is stored in the storage device within the CPU 14.
Since the temporal change and temperature change characteristics of the transducer 6 can be stored and the zero point of the transducer 6 can be constantly adjusted, precise measurement is possible.

Next, the second invention will be explained with reference to FIGS. 4 and 5.

This invention is extremely useful when placing large objects to be weighed, such as 10- or 15-k!IO, on the weighing pan 3 all at once.

In FIG. 4, the support rod 3a of the weighing pan 3 is divided into two parts, an upper and a lower part, and a load cell 26 is interposed between the parts.

The load cell 26 detects only the weight of the object placed on the weighing pan 3, regardless of the imbalance of the scale rod 2.

Since the load cell 26 detects the approximate weight of the object to be weighed on the weighing pan 3 prior to precise measurement, it is sufficient even if the load cell 26 has a relatively large error.

The output of the load cell 26 is sent to an N-D converter 28 via an amplifier 27, where it is converted into a digital signal and then converted into a digital signal.
It is input to PU14.

Since the other configurations are the same as those shown in FIG. 1, the explanation will be omitted.

The outputs of both the transducer 6 and the load cell 26 are input to the CPU 14, and the operations shown in FIG. 5 are performed.

In response to the start signal, the data value (d) from the load cell 26 is first read and compared with a predetermined set value (do).

This set value (do) is preferably set within the measurable range of the transducer 6 (in the above example, 2←inside the ship, and more preferably within the precise measurement range (do≦500).

Here, do=500 is set.

If the read data value (d) is d < d o,
Next, the data value (D) from the transducer 6 is read, added and displayed in the same manner as in the first invention.

If it is the first time and the memory contents of register A are zero,
The data value (D) is displayed as is.

The subsequent execution programs are almost the same as in the first invention.

However, here, 50 from the upper limit of the measurement range (20000)
The difference is that setting values (Dn) are set in 40 steps up to 0.

Then, if d > d o, the data value (
d) with these set values (Dn).

Therefore, through this comparison operation, it is determined approximately how much the weight of the object to be weighed placed on the weighing pan 3 is, and a weight 5 having a weight close to this weight is added to the mounting table 4. It is not necessary to perform weight addition/removal operations many times as in invention 1, but only 2 to 3 times at most (therefore, 1(S)
Precision weighing is completed with the following steps.

Also, if the data value (d) exceeds 20-,
An overflow event will be held.

As explained in detail above, the first invention inputs the output of the transducer for detecting the unbalance of the scale rod supported on the fulcrum to the CPU, and operates the weight adding/removing device based on the output from the CPU. The total weight of the weights being controlled and added to the scale rod,
This is a method of calculating the sum of the output of a transducer and a detected weight within a predetermined range, and is a method of measuring using a CPU, which includes the following steps.

(b) Read the data value (D) (portion) Add the data value (D) and the memorized weight weight and display it (c) Compare the data value (D) and the predetermined setting value (Dn) and read the IDI When ≦Dn, return to (a) above) ID
When I>Dn, determine the polarity of the data value (D).(e) Add or subtract the set value (Dn) to the memorized weight according to the polarity, and store this added/subtracted value.(f) Adjust the weight according to the added/subtracted value. The addition/removal signal is output, and the process returns to (a) above after the time required for the weight addition/removal operation has elapsed. Therefore, the selection of the combination of weights to be added, the control of the weight addition/removal device, and the calculation of the weight value can be performed all at once, making it possible to accurately and Can be weighed quickly.

In addition, the CPU is used to not only display, but also print and record, set the desired weight value, display the deviation between the set value and the weight value, calculate and display the cumulative total of a series of weighing operations, and record the number of weighing operations. It is extremely convenient because it allows counting and display, as well as zero point adjustment of the transducer.

In addition, as one embodiment of the present invention, the predetermined setting value (Dn) in step 0→ is set in multiple stages, so it is possible to discriminate between multiple stages of data value (D), and the weighing operation can be extremely improved. It can be made faster.

Furthermore, as another embodiment, the output from the transducer is taken out to an excess range that exceeds the range in which precise measurement is possible, and which has a certain degree of error, and the minimum value of the predetermined set value (Dn). is set within the precision measurement range, the output of the transducer can be effectively utilized over a wide range, and the measurement accuracy can be extremely high.

A second invention further includes, in addition to the first invention, the output of a load cell that detects the weight of the object to be weighed on the weighing pan located at one end of the weighing rod is input to the CPU,
reading a data value (d) from the load cell;
Since a step of comparing this data value (d) with a predetermined set value (do) is added, even when a relatively heavy object is placed on the weighing pan, it can be weighed extremely quickly and with high precision. can be done.

In one embodiment of the second invention, the set value (do
) is set within the measurement range of the transducer, further speeding up the weighing operation.

Furthermore, in other embodiments, the set value (Dn) is set in multiple stages, which also contributes to speeding up the metering operation.

In yet another embodiment, the maximum value of the set value (Dn) is set as the upper limit of the measurement range, and when the data value (d, D) exceeds this maximum value, an overflow (R) is displayed. From this display, it can be immediately determined that the object to be weighed on the weighing pan cannot be weighed.

[Brief explanation of drawings]

1 to 3 are for explaining the first invention, in which FIG. 1 is a schematic configuration diagram of the measuring device, FIG. 2 is a graph showing the output characteristics of the transducer, and FIG. 3 is a graph showing the output characteristics of the transducer. is a flowchart of an execution program, FIGS. 4 and 5 are for explaining the second invention, FIG. 4 is a schematic configuration diagram showing a part of the measuring device, and FIG. 5 is a flowchart of an execution program. be. 1... fulcrum, 2... scale rod, 5...
... Weight, 6 ... Transducer, 13 ...
... Weight adjustment device, 14 ... Micro computer, 26 ... Load cell. 51-

Claims (1)

[Claims] 1. The output of a transducer that detects the imbalance of a scale rod supported on a fulcrum is inputted into a computer, and a weight adjustment device is controlled based on the output from the computer, A method of weighing by calculating the sum of the total weight of the weights held and the detected weight within a predetermined range of the output of the transducer, the method using a microcomputer and comprising the following steps. (B) Read the data value rD) (Ex) Add the data value (D) and the memorized weight weight and display it (C) Compare the data value (D) and the predetermined set value (Dn) l D l <If Dn, return to (a) above)
When IDI>Dn, determine the polarity of the data value (D) (e) Add or subtract the set value (Dn) to the memorized weight according to the polarity, and store this added/subtracted value (f) Adjust the weight according to the added/subtracted value Output the addition/subtraction signal and return to the above (a) after the time required for the weight addition/subtraction operation (2 steps)
A measuring method using a microcomputer according to claim 1, wherein the predetermined setting value (Dn) in c) is set in multiple stages. 3. Claim 2, in which a detection output is obtained from the transducer to a range beyond the precision measurement range, and the minimum value of the predetermined set value (Dn) is set within the precision measurement range.
Weighing method using a microcomputer as described in section. 4 Input into a computer the output of a transducer that detects the unbalance of the scale rod supported on the fulcrum, and the output of the load cell that detects the weight of the object to be weighed on the weighing pan at one end of the scale rod, and A method of weighing by controlling a weight addition/removal device based on the output from a computer and calculating the sum of the total weight of the weights added to the scale rod and the detected weight within a predetermined range from the output of the transducer. A weighing method using a microcomputer that consists of the following steps. (b) Read the data value (d) from the load cell (mouth)
Compare the data value (d) and the predetermined setting value (do) and d>d
When o, move to the following (e) (c) When d < d o, read the deku value (D) from the transducer) Add the data f direct D) and the memorized weight weight, and display. (e) Compare the data value (d, D) and the predetermined setting value (Dn), and when d, l DI < I) return to the above (c) (v) d, when IDI>Dn Data value (
(d) Determine the polarity of D) (g) Add or subtract the set value (Dn) to the memorized weight weight according to the polarity, and store this addition/subtraction value (e.g., output a weight addition/division signal according to the added/subtracted value, and After the time required for the addition/subtraction operation has passed, return to the above (c) step 5 (
5. The microcomputer-based measuring method according to claim 4, wherein the predetermined set value (do) in (b) is set within the measurement range of the transducer. 6. A measuring method using a microcomputer according to claim 4 or 5, wherein the predetermined setting value (Dn) in step (E) is set in multiple stages. 7. The microcontroller according to claim 6, wherein the maximum value of the predetermined set value (Dn) is the upper limit of the measurement range, and when the data value (d, D) exceeds this maximum value, an overflow (R) is displayed.・Computer-based weighing method.