JPS59195129A - Integrating meter for belt scale - Google Patents

Abstract

PURPOSE:To find out an integrated value highly accurately independently of external conditions by using a pulse signal generated in accordance with the moving distance of a belt of a measuring conveyer as a starting signal and summing up the output of a weighting circuit. CONSTITUTION:If a belt is carried at the maximum instantaneous weight and the maximum belt speed, moving pulse signals in the unit length of the belt are outputted by 100 pulses per second, received by an input terminal 22 and inputted to a summing circuit 27 through the M terminal of an alteration switch 33. Subsequently, 0.1 is outputted from the weighting circuit 26 and the value 0.1 is added to the preceding summed value every input of a pulse signal P1 to the circuit 27. In one hour, 0.1 is summed by 360,000 times from 100pulses/secX 3,600sec, the summed result is 36,000 and carrying quantity 36,000kg is displayed in a display circuit 28. Since the summing of one time requires 0.01 second, integration can be performed instantaneously, and if the weighting value of the circuit 26 is set up to a small value, the integration accuracy can be increased in accordance with the weighting value.

Description

[Detailed description of the invention] The present invention relates to a belt scale totalizer.

Conventionally, this type of totalizer uses a pressure sensor 3 such as a load cell to detect the instantaneous weight applied to a certain section of a weighing conveyor 2 carrying an object 1 to be weighed, as shown in FIG.
It receives an analog signal (voltage or current) proportional to the instantaneous weight output from the voltage converter 4, and at the same time receives a pulse signal output from the pulse generator 5 in accordance with the amount of belt movement of the weighing conveyor 2. The instantaneous transport amount is determined by a multiplication circuit 6 using an analog switch, and the multiplication result as the instantaneous transport amount becomes a pulse signal with a constant time width and different heights.After smoothing with a built-in integration circuit, The pulses are inputted to a V/F conversion circuit 7 that converts them into a pulse signal with a frequency proportional to the analog voltage, and the pulses are counted by a counter circuit 8 to obtain an integrated value.

However, because the circuit elements that make up conventional totalizers, such as the multiplier circuit 6 and the V/F converter circuit 7, mainly perform analog processing, voltage and current drift may occur due to the influence of external environmental conditions, especially temperature changes. This caused an error in the instantaneous weight.

In addition, the power supplied to the power supply circuit 9 is usually shared with other devices in the environment in which the belt scale device is installed, and there are fluctuations in the voltage supplied to each circuit from the power supply circuit 9, resulting in instantaneous fluctuations. As a result of the error in weight, a considerable error may occur in the integrated value obtained by the counter circuit 8.

In addition, in order to accurately measure the instantaneous weight on the conveyor,
Increasing the number of divisions to reduce the weight value per unit pulse, that is, the V/F adjustment circuit 7 based on the output of the scaler circuit 1o.
It would be better to increase the number of pulses generated in there were.

As described above, conventional totalizers have many drawbacks due to analog processing and problems when aiming for high accuracy.

The present invention was made in view of the above-mentioned drawbacks and problems, and an object of the present invention is to provide a totalizer for a belt scale whose integrated value is not affected by external conditions and which allows highly accurate weighing.

In order to achieve the above object, the basic idea leading to the present invention was to firstly convert from a conventional circuit system centered on analog processing to a circuit system centered on digital processing, and second, to use a counter circuit to The system eliminates the need to count pulses and uses an accumulator circuit to instantaneously obtain the integrated value, which outputs an output proportional to the instantaneous weight applied to a certain section of the weighing conveyor that transports the object to be weighed. An analog-to-digital conversion circuit that converts an analog signal into a digital signal, a multiplication circuit that multiplies the output from this analog-to-digital conversion circuit and preset maximum capacity (scale) data for flow rate, and an output of this multiplication circuit. A weighting circuit that assigns predetermined weight data to
The basic feature is that the weighing apparatus is equipped with an accumulation circuit that accumulates the output of the weighting circuit using a pulse signal generated in accordance with the amount of belt movement of the weighing conveyor as a starting signal.

Hereinafter, embodiments of the present invention will be described in more detail in terms of the overall structure including the embodiments.

In FIG. 2, the totalizer 20 of one embodiment is equipped with an instantaneous weight input terminal 21 and a terminal 22 for belt movement pulse. An analog signal (eg, a voltage signal) proportional to weight is received, and input terminal 22 receives a pulse signal generated in response to the belt travel path of the weighing conveyor.

23 is an analog-to-digital conversion circuit that converts the analog signal from the instantaneous weight input terminal 21 into a digital signal (for example, a binary code signal); 24 is comprised of a digital signal from the analog-to-digital conversion circuit 23 and a switch. This is a multiplication circuit that multiplies the maximum capacity data of the flow rate set in the scale factor setting device 25. In this example, the scale factor is the capacity per hour (t/h) of the scale.
or Ky/h).

26 is a weighting circuit that applies a predetermined weight W to the output of the multiplication circuit 24 to facilitate subsequent calculations; in this example, a division circuit that divides the output of the multiplication circuit 24 by a constant; It is said that

Therefore, the constant corresponds to w-4 in relation to the weight W.

Reference numeral 27 denotes an accumulation circuit that accumulates the output of the weighting circuit 26 using the pulse signal P1 as a starting signal, and the pulse signal P1 is a pulse signal received at the terminal 22 to the belt movement amount pulse. Reference numeral 28 is a display circuit that converts the accumulation result (binary code format) of the accumulation circuit 27 into a decimal number and displays the total weight of the objects to be weighed conveyed by the conveyor.

Note that 29 and 30 are circuits for correcting digital signals from the analog-digital conversion circuit 23, and the arithmetic circuit 29 is for adjusting the zero point of the instantaneous weight measured using zero point data stored in advance in the memory 31. , arithmetic circuit 3
o is for adjusting the instantaneous weight span using span data stored in advance in the memory 32, and details of these will be described later. The 3-unit, 3-output, 3-terminal switch 33 is a mode switching switch, and is switched to terminal M in normal integration mode, switched to terminal Z in zero point adjustment mode, and switched to terminal S in span adjustment mode.

The operation of the embodiment of the present invention will be explained using a specific example.

The premise is that the belt length of the weighing conveyor is 10 m, the belt speed is l Qm/min, and 6000 pulse signals are generated over the entire length of the belt, 2500 is set in the zero point adjustment memory 31, and 2500 is set in the span adjustment memory 32. A span factor i and oooo (reference value) are set in . Further, the maximum capacity of the scale is 35 t/h, and 36 is set in the scale factor setter 25, and the value of K in the weighting circuit 26 is previously selected to be 3,600,000.

The analog-digital conversion circuit 23 outputs 2500 when the instantaneous weight is zero, and 12500 when the instantaneous weight is maximum (both are binary codes, but are shown in decimal format for simplicity.

) is output, and the arithmetic circuit 29 subtracts 2500 from this output signal at a rate, resulting in an output range of 0 to 10000.

The span factor is 1. (Since it is 1000, the output of the arithmetic circuit 30 as a multiplication circuit is O~1.0000,
The output signal within this range is input to the multiplication circuit 24.

The multiplier circuit 24 multiplies the output of the arithmetic circuit 30 by 36,
The output range is O to 360,000, and K is 360,000.
With the weighting selected as 0, the output of the circuit 26 is O~360000.
/3600000 becomes O~0,1.

Now, assuming that the belt is being conveyed with the maximum instantaneous weight and the maximum belt speed, 100 movement pulse signals per unit length of the belt are output per second, received by the input terminal 22, and transferred to the selector switch 33. It is input to the accumulation circuit 27 via the terminal. The weighting circuit 26 outputs 0.1, and each time the pulse signal P1 is input to the accumulation circuit 27, the weighting is changed to 0.1.
1 is added to the previous accumulated value. In one hour, 0.1 is accumulated 360,000 times from 100 pulses/second x 3,600 seconds, and the accumulated result is 36,000, and the display circuit 2
8, 9 (361) is displayed in the conveyance amount of 36,000.

In the above embodiment, since one accumulation takes 1-second, the accumulation can be accomplished almost instantaneously, and the accumulation circuit 2
In consideration of the processing time in step 7, weighting is performed using the weight W of the circuit 26.
If the value of (-K) is made sufficiently small (the number of divisions is made large, that is, the instantaneous weight per pulse signal is made small)
, the integration accuracy can be greatly increased according to this smallness.

Next, the zero point adjustment circuit will be explained.

If an error occurs in the zero point of the scale due to the instantaneous weight detection unit or the attachment of the object to be measured to the belt, the output of the analog-to-digital conversion circuit 23 will not be the correct weighing value, and if it is integrated as it is, the integrated value will be incorrect. This is provided to prevent this from occurring. The zero point adjustment circuit described below does not take the form of obtaining zero point data using a separate circuit means, but is built into the totalizer of this embodiment in a relatively simple form, and moreover, Circuit (2
An accumulation circuit (39) similar to 7) is provided to obtain zero point adjustment (hereinafter referred to as "zero adjustment") data with high precision.

That is, the weighing conveyor is set to run empty, and the belt rotation speed (integer) for performing zero adjustment is set in the belt rotation speed setting device 33, and the number of emitted pulses per revolution of the belt is set in the belt pulse setting device 34. Set to . When the data is set, the arithmetic circuit 35 calculates the number of pulses corresponding to the belt length targeted for zero adjustment. When the mode selector switch 33 is switched to the Z terminal side and the calibration push button 36 is turned on,
The gate circuit 37 is opened, and the pulse signal per unit length of belt movement input to the pulse input terminal 22 is counted by the counter 38. At the same time, the pulse signal that has passed through the gate circuit 37 is given to the accumulator circuit 39 via the Z terminal of the mode changeover switch 33-3 in the third stage, and from the analog-digital conversion circuit 23 to the first stage switch 33-3. The instantaneous empty weight inputted to the accumulation circuit 39 through the Z terminal of No. 1 is accumulated.

The contents of the counter 38 are stored in the comparator circuit 40 by the arithmetic circuit 3.
5, and if they match, a match signal is output from the comparison circuit 40 to the gate circuit 37.
is closed. Counting by the counter 38 and processing by the accumulating circuit 39 are stopped. In the accumulating circuit 39, an accumulated value of the instantaneous weight zero point output corresponding to the number of Knolls signals corresponding to the set belt length is created. By dividing by the output (the number of pulse signals corresponding to the belt length), the zero point output per pulse signal is obtained.This zero point output value is displayed on the display 42, and when manual acceptance (Manual; ML) is performed. is an index of the zero factor, which is read and set in the zero factor setter 43 consisting of a switch, and is given to the memory 31 via the acceptance changeover switch 44. In the case of automatic acceptance (Auto; A), the division The output of the circuit 41 is transferred to the memory 3 through the A terminal of the selector switch 44.
1 is directly rewritten and used as zero point data for subsequent integration processing.

To give a specific example, if the number of pulses per circumference of the belt is 6000 and 13 rotations of the belt is acceptable, then the belt pulse setting device 3
3 to 6000 and belt rotation speed setting device 34 to 3. The output of the arithmetic circuit 35 becomes 18000, and when the mode selector switch 33 is switched to the Z terminal side and the calibration push button 36 is turned on, the gate circuit 37 opens and the counter 38 starts counting. At the same time, the accumulating circuit 39 accumulates the output of the analog-to-digital converter 23 (of course, the accumulated contents are cleared before starting the accumulation). Counter 38 is 180
When it reaches 00, the gate circuit 37 is closed and counting and accumulation are stopped. The contents of the accumulation circuit 39 at this time are 45018
000, the calculation circuit 41 is 45018000/1
Execute 8000 and output 2501. By storing this zero point data 2501 in the memory 31, accurate instantaneous weight can be obtained by subtracting the memory contents 2501 from the output from the analog-to-digital conversion circuit 23 in the subtraction circuit 29 in the integration mode (M). That is.

Note that here, the correct zero point output from the analog-digital conversion circuit 23 is set to 2500, but even if the zero point output is determined to be 0, the accumulator circuit 39 and the arithmetic circuit 41 should be operated including the positive and negative signs. A similar admission can be performed by

Next, the span adjustment circuit will be explained.

The span adjustment circuit prevents the output of the analog-to-digital conversion circuit 23 from becoming a predetermined correct measured value if an error occurs in the span of the instantaneous weight detection section, and an error will occur in the integrated value if it is integrated as it is. It is provided for. The span adjustment circuit described below does not require a separate circuit means to obtain span factor data to be corrected, but is built into the totalizer of this embodiment in a relatively simple manner, and is An accumulation circuit (50) similar to the accumulation circuit (27) according to the embodiment is provided so that correction data for span adjustment can be obtained with high precision.

That is, the belt rotational speed for performing span adjustment is set in the belt rotational speed setting device 34, and the number of pulses to be transmitted per revolution of the belt is set in the belt pulse setting device 33. The arithmetic circuit 35 calculates the total number of pulses corresponding to the belt length subject to span adjustment.

On the other hand, in order to set the reference instantaneous weight in advance, a test chain is placed on the belt or the instantaneous weight is added directly to the instantaneous weight detection section using a test weight, and the obtained reference instantaneous weight is set in the reference weight setting device 45. At the same time, the length of one circumference of the belt is set in the belt circumference setting device 46. After each data is set, the arithmetic circuit 47 multiplies the reference instantaneous weight data and one belt circumference data to obtain an integrated value of the pel 11 circumference. In the next arithmetic circuit 48,
This integrated value is multiplied by the belt rotation speed data from the belt rotation speed setting device 34. This multiplication result becomes a reference integrated value for span adjustment and is applied to the span factor calculation circuit 49.

When the mode selector switch 33 is switched to the S terminal side and the calibration push button 36 is turned on, the gate circuit 37 is opened and the pulse signal of the belt movement amount input to the pulse input terminal 22 is counted by the counter 38. At the same time, the pulse signal that has passed through the gate circuit 37 is given to the accumulation circuit 50 via the S terminal of the third-stage mode changeover switch 33-3, and the weighting is performed by accumulating the basic instantaneous weight from the circuit 26. do.

The contents of the counter 38 are stored in the comparator circuit 40 by the arithmetic circuit 3.
5, and if they match, a match signal is output from the comparison circuit 40 to the gate circuit 37.
is closed. Counting by the counter 38 and processing by the accumulating circuit 50 are stopped. In the accumulator circuit 50, an accumulated value is created that is influenced by the span factor SP (set in the memory 32) at the time of calibration. This integrated value SW can also be displayed on the display circuit 28 via a gate circuit 51 that allows this data to pass in the span mode.

The integrated value SWI of the accumulator circuit 50 is calculated by the arithmetic circuit 49 based on the reference integrated value w s T from the arithmetic circuit 48 and the span factor SP at the time of calibration.
I is calculated and a new span factor is calculated. The calculation result is displayed on the display circuit 42. During manual span adjustment, the displayed content becomes a span factor index and is set in a span factor setter 52 composed of a switch, and then provided to the memory 32 via a span changeover switch 53. When automatically setting span adjustment data, the output of the arithmetic circuit 49 is directly rewritten in the memory 32 with new span data via the A terminal of the span changeover switch 53.

To give a specific example, assume that the number of pulses per rotation of the belt is 6000, the span is adjusted by three revolutions of the belt, the length of one belt circumference is 10 m, the reference instantaneous weight is 60 Kli'/m, and the scale capacity is 35 t/h. . Belt pulse setting device 33 to 6
000, 3 to the belt rotation speed setting device 34, 10 to the belt 1 circumference setting device 46, and 6 to the reference weight setting device 45.
Set to 0. The memory 32 is set to 1.0.

The output of the arithmetic circuit 35 is 6000 x 3 = 1800
It becomes 0. On the other hand, the output of the arithmetic circuit 47 is 60x10-6
00, and the output of the arithmetic circuit 48 is 600×3=1'8
00 (KP) (Hertopa/l/S100 H2%
Output of operation operation 35 18000 to 18000/100
From X60=3 (minutes), the standard integrated value for 3 minutes for a capacity of 36 t/h) is obtained.

When the mode changeover switch 33 is set to S and the calibration push button 36 is turned on, the gate circuit 37 opens, the counter 38 starts counting, and at the same time the accumulation circuit 50 accumulates the instantaneous weight (of course, before the accumulation, the previous content is cleared). When the counter 38 reaches 18,000, the gate circuit 37 closes and stops counting and accumulation, and the content of the accumulator circuit 50 at this time is 18,000.
00, the arithmetic circuit 49 outputs 1.0 from 1.0X1800/1800, but if the content is 1900,
1.0X1800/1900 to 0.9473...
... is output, and subsequent span adjustment is performed by storing this value in the memory 32.

By the way, in the embodiment shown in Fig. 2, data necessary for calibration at the time of calibration (acceptance, span adjustment), namely the number of pulses per circumference of the belt, the number of rotations of the belt (integer), the length of one circumference of the belt, and the test Belt pulse setting device 33 that independently sets the reference instantaneous weight of the chain and test weight.
．． Belt rotation speed setting device 34. A belt one circumference setting device 46 and a reference weight setting device 45 are provided. This is traditionally the zero point.

The data required to calibrate span, etc. is the total belt length (pulse number) to stop the calibration operation from the number of pulses per belt rotation and the belt rotation speed, and the reference instantaneous weight from the test chain or test weight and the belt rotation speed. The standard integrated value was manually calculated from the belt length and belt rotation speed and used as setting data, but this eliminates the inconvenience of having to manually calculate it again when one parameter is changed, and improves internal The data setting is automated through calculation.

In addition, by making it possible to set each data independently as in this example, it is possible to use a general-purpose totalizer that is not affected by the conditions on the weighing conveyor side, such as the belt length or the specifications of the pulse generator, without having to use a totalizer exclusively for that weighing conveyor. It has a sexual nature.

In the embodiment shown in FIG. 2 above, a certain block has been explained as a functional circuit such as arithmetic, accumulation, etc. as a node, but in this way, a functional circuit block can be an electronic controller of one or several chips. Of course, it is also possible to replace it with software (program) of a means (for example, a microcomputer). Although the disclosure of a specific program will be omitted, this type of program can be constructed relatively easily by those skilled in the art based on the disclosure of the present invention.

Furthermore, regarding the above embodiment, in the output signal of the analog-digital conversion circuit 23, the previous output value is stored and compared with the current output value, and when the difference is greater than a predetermined value (the fluctuation is (when the difference is too large), a circuit for issuing a warning or a circuit for correction may be provided depending on the difference. As the correction circuit, an interpolation calculation circuit is provided, for example, a circuit that calculates (previous output value + current output value)/2 and outputs the calculation result to the multiplication circuit 24 side of maximum capacity data.

As explained in detail above, the present invention converts the instantaneous weight analog signal into a digital signal and is basically configured with a circuit system centered on digital processing, so the obtained integrated value is not affected by external conditions such as temperature. In addition, the pulse signal of the belt movement is used as the starting signal to integrate the instantaneous weight of the thin tray, so compared to the conventional pulse counting method, the present invention has virtually no restriction on the minimum unit, and therefore the integration can be performed with high precision. There are effects that can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional example, and FIG. 2 is a block diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Object to be weighed, 2... Weighing conveyor, 4... Load-voltage converter, 5- Pulse generator, 23... Analog-digital conversion circuit, 24... Maximum capacity data multiplication Circuit, 26... Weighting circuit, 27... Accumulation circuit, Pl... Pulse signal serving as a starting signal for accumulation.

Claims (1)

[Claims] +1+ An analog signal output in proportion to the instantaneous weight applied to a certain section of the weighing conveyor that conveys the object to be weighed,
In a belt scale totalizer that receives a pulse signal generated in accordance with the amount of belt movement of the weighing conveyor and totalizes the total weight of the conveyed object, an analog signal that converts the analog signal into a digital signal is used. A digital conversion circuit, a multiplication circuit that multiplies preset flow rate maximum capacity data by the output from the analog digital conversion circuit, and a weighting circuit that applies preset weight data to the output of the multiplication circuit. A totalizer for a Suru1 belt scale, comprising: a circuit; and an accumulating circuit for accumulating the output of the weighting circuit using the pulse signal as a starting signal.