CN109767887B - Method for combining given output resistance values in series-parallel connection - Google Patents

Method for combining given output resistance values in series-parallel connection Download PDF

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CN109767887B
CN109767887B CN201910110506.0A CN201910110506A CN109767887B CN 109767887 B CN109767887 B CN 109767887B CN 201910110506 A CN201910110506 A CN 201910110506A CN 109767887 B CN109767887 B CN 109767887B
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resistor
omega
bit
resistance
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CN109767887A (en
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陈渝
周黎明
谭建华
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Chengdu CAIC Electronics Co Ltd
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Chengdu CAIC Electronics Co Ltd
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Abstract

The invention discloses a method for combining given output resistance values in series-parallel connection, and aims to provide a method for combining given output resistance values in series-parallel connection, which is given rapidly and has high precision and accuracy. The invention is realized by the following technical scheme: the hundred-bit resistor combination with the interval value of 100 omega and the equi-differential series resistance value of which the range of an access circuit is 0 to 900 omega is formed by adopting 4 resistor units of 200 omega and 1 resistor unit of 100 omega in series connection; the ten-bit resistor combination with the range of the access circuit of 0 to 90 omega is formed by connecting the resistor combination in series according to the mode with the interval value of 10 omega; the bit resistor combination with the range of 0 to 9 omega of the access circuit is formed according to the mode with the interval value of 1 omega; the interval value is 0.1 omega, and the ten-bit resistor combination with the range of the access circuit of 0 omega-0.9 omega is formed in the mode; thus, a resistance with a maximum composition of 900+90+9+0.9=999.9Ω and a minimum resolution of 0.1 Ω is given.

Description

Method for combining given output resistance values in series-parallel connection
Technical Field
The invention is mainly used for providing a method for combining a given output resistance value in series-parallel connection of a test environment of a resistance signal.
Background
Resistors, capacitors, and inductors are the most commonly used devices and types in electronic circuits. The resistor is classified into a fixed resistor and a variable resistor. The adjustable resistor is a resistor which can play a role of a resistor in an electronic circuit and is different from a common resistor in that the resistance value can be continuously changed in a certain range, and the adjustable resistor can be used in occasions requiring the change of the resistance value and not to be changed. The adjustable resistor has a fault occurrence rate which is obviously higher than that of the common resistor due to the structure and the use. The adjustable resistor has various varieties and different structures, and the definition of each resistor is different. The pair-winding adjustable resistor is formed by winding a resistor wire on a framework to form a circular or spiral resistor body, and the pair-winding adjustable resistor is formed by forming a resistor film on a public substrate, wherein the shape of the resistor film is a horseshoe shape, a circular arc shape or a strip shape. For the composite solid adjustable resistor, a horse-shoe shaped or long strip-shaped resistor rail is compression molded on a base. The movable contact member is called a brush or a contact type in-brush. A variable resistor is an electromechanical element that relies on a slider that slides over a resistor body to change the resistance of the resistor. The variable resistor can be divided into a varistor and a potentiometer according to the purpose of the variable resistor, and the varistor is also often called an adjustable resistor, and is characterized in that the resistance value can be changed by changing the position of a sliding sheet. The potentiometer is a voltage divider, which slides on a resistor body by means of a sliding vane to obtain an output voltage which is in a certain relation with the displacement of the sliding vane. The potentiometer can also be used as a rheostat, and the rheostat is formed by connecting the center tap with any one of the other two pins. The resistor is used to measure whether the resistance value of the resistor is consistent with the nominal value. The potentiometer is actually a variable resistor and can be made of various materials. The potentiometer is generally composed of two fixed outputs and a sliding tap. The potentiometer can be divided into a single circle and a plurality of circles according to the structure; single-link and double-link; with a switch; locking and unlocking potentiometers. The adjustable potentiometer is divided into a rotary potentiometer and a straight sliding potentiometer according to an adjusting mode. In the rotary potentiometer, the relationship between the resistance value and the rotation angle of the potentiometer can be classified into a linear type, an exponential type, and an logarithmic type. When the variable resistor changes the resistance value, the movable contact moves on the surface of the resistor due to the reasons of improper distribution of the adjustable resistor, improper matching of a rotating system, contact resistance of the adjustable resistor and the like, the output end is accompanied by contact noise, resolution noise and short circuit noise with variable signal fluctuation besides a useful signal, the resolution noise is caused by the gradient of resistance change, and the short circuit noise is generated when the movable contact moves on the winding to short circuit adjacent turns. For wire wound and linear adjustable resistances, the resolution is expressed as a percentage of the total resistance to the amount of resistance change caused by each turn of the moving contact on the winding. For an adjustable resistance with a functional characteristic, resolution is a variable because the resistance of each turn on the winding is different. At this time, the resolution of the adjustable resistor refers to the average resolution of the section with the largest slope on the function characteristic curve. The usual varistors are in the form of a sliding varistor, a resistor box or the like, which is a varistor for voltage division consisting of a resistor body and a rotary or sliding system. The resistance value is typically changed by winding a resistance wire into a coil, and sliding a slider to change the length of the resistance wire that is connected to the circuit. The slide rheostat can change the resistance of the connected circuit, and has the function of continuously changing the current, but the resistance value of the connected circuit cannot be accurately known. If the resistance of the resistor connected to the circuit needs to be known, a resistor box is used. The resistor box is a combination of a plurality of fixed-value precise resistors, which are arranged in the same box, and the box-type resistor with the resistance value changed by the conversion device is a rheostat which can adjust the resistance and can display the resistance value. Such devices typically employ a decade disc (knob) configuration, as well as plug and knob configurations, as desired. It is compared with a sliding rheostat, which cannot show the resistance value of the connected-in circuit, but it can continuously change the resistance in the connected-in circuit. The resistor box can show the resistance value in the connected circuit, but the resistance value change is discontinuous and has no slide rheostat value change standard.
In the manufacture and application of the sensor, the idea of converting the change of the measured non-electric quantity (such as displacement, force, acceleration, torque, pressure and the like) into a resistance-change resistance sensor, a capacitance-change capacitance sensor and an inductance-change inductance sensor is to convert the physical quantity to be acquired into corresponding resistance, capacitance and inductance, and the output of the sensor is the corresponding change of the resistance value, the capacitance value and the inductance value respectively. The resistance of the analog resistance signal of the resistive sensor is generally set to be 0 to 999.9Ω and the resolution is 0.1Ω. In the system joint test, for example, the joint test of the resistance type sensor and the system, the corresponding resistor can be used for simulating the change of the resistance type sensor, meanwhile, the change of the resistor or the resistance value is known in the setting process, and the resistance quantity of any resistance value in the range of the setting range of the resistance type sensor can be simulated.
Disclosure of Invention
The invention aims to provide a method for combining a given output resistance value in series-parallel connection, which has the advantages of simple and convenient given implementation, low cost, quick given operation, high precision and accuracy.
The invention is achieved by the following measures, and the method for combining the given output resistance values in series-parallel connection has the following technical characteristics: at least 4 resistor units with 200 omega and 1 resistor unit with 100 omega are adopted at intervals of 100 omega to form a hundred bit resistor combination body with the range of an access circuit ranging from 0 omega to 900 omega in series; the ten-bit resistor combination with the interval value of 10Ω, at least 4 resistor units of 20Ω and 1 resistor unit of 10Ω and the series connection form an arithmetic series resistance with the range of 0 Ω -90Ω; at least 4 resistance units with interval value of 1 omega and at least 4 resistance units with interval value of 2 omega and 1 are connected in series to form an electric bit resistance assembly with an arithmetic series resistance value with the range of 0 omega-9 omega of an access circuit; at least 4 resistor units with interval value of 0.1 omega and 1 resistor unit with interval value of 0.2 omega are connected in series to form a ten-bit resistor combination with an equidifferent number series resistance value with the range of 0 omega-0.9 omega; thus, the maximum values of hundred-bit, ten-bit, unit-bit and ten-bit resistor combinations are added, the maximum value is 900+90+9+0.9=999.9Ω, the minimum resolution is 0.1Ω, and a double-knife double-linked switch switching relay which is connected in parallel at intervals on a series line is arranged between each two adjacent series resistors, the number of short contacts of the relay on the resistance output loop is counted by the variable resistor singlechip system, and the accumulated total resistance value of the closed contacts of the relay is subtracted from the combined output resistance value.
Compared with the prior art, the invention has the following beneficial effects.
The realization is simple. The invention adopts the serial structures of hundred-bit series resistor groups, ten-bit series resistor groups, unit series resistor groups and ten-bit series resistor groups to form an output resistor, uses the separation modes of hundred-bit, ten-bit, unit and ten-bit series resistor groups to combine, achieves the required resistor through the serial combination of resistors, adopts a relay contact to short the redundant resistor to achieve the target resistor, and realizes the relay contact resistance at the short-circuit resistor through the relay double-knife parallel connection to halve the contact resistance, obtains the target resistance value at each bit of the series resistor groups, and obtains any resistance value of 0-999.99 omega by using fewer series resistor groups in each group, thereby being simple to realize. Many resources can be saved under the condition of the same precision. Meanwhile, the resistance value of the resistor is adjusted through the external digital control device, intelligent adjustment of the resistance value of the resistor can be realized, the efficiency of resistance value adjustment is higher, and damage to a circuit can be avoided.
The cost is low. The invention uses the resistor combination mode to complete the variable resistor, especially has advantages in high precision and low cost. The resistors with the deviation of the resistance values are all goods shelf products, and only the goods shelf resistance XJ3 type precise wire-wound resistor is provided by a resistor manufacturer without independent customization. The assembly and adjustment are simple and convenient. Each series resistor group is alternately arranged according to positive deviation and negative deviation, so that magnitude output with better accuracy can be obtained, and only simple secondary matching is needed, so that the workload is small.
Given the rapidity. When the invention outputs any resistance value of 0-999.99Ω, the hundred-bit, ten-bit, one-bit and ten-bit relay contacts are short-circuited according to the combination requirement to achieve the output of a target resistance, each resistance unit combination corresponds to 1-9 selective output, each resistance unit combination is provided with a corresponding fixed relay contact closing combination, the number of the relays on a resistance output loop can be counted according to the output of each resistance value, the accumulated total resistance value of the relay closing contacts is subtracted from the final resistance combined output resistance value, and the invention has the advantages of simple and convenient given implementation, quick response, good resistance stability, smaller resistance temperature coefficient and noise. The single chip microcomputer is controlled by the single chip microcomputer, the single chip microcomputer is connected with an upper computer through a serial RS485 bus, the upper computer gives out a target resistance value, and the resistance output is completed within 0.3 s. Each resistor array combination is matched positively and negatively. The positive deviation and the negative deviation of the resistance value are alternately arranged, the resistance value magnitude output with better accuracy is obtained, the full-range precision and the accuracy of the resistance value are still considered to be +/-0.025%, and the full-range precision and the accuracy are better than 0.25Ω and are still unchanged. This requires secondary screening and pairing, which is relatively less labor intensive.
The precision is high. According to the invention, the required resistance is achieved through series combination of the resistors, the maximum value of each series resistor group is added to form a resistor given device with the maximum value of 999.9 omega and the minimum resolution of 0.1 omega, and the precision is improved in a parallel connection mode of a plurality of resistors in different combination modes; and the relay which is connected by double knives is connected in parallel on 4 series resistance interval series lines of each group, the relay contact resistance at the position of the short circuit resistor R is halved by the double knives of the relay in parallel connection, each resistance unit corresponds to the closing of a fixed relay contact, the contact resistance is reduced by 1-9 selection output, the relay contact resistance at the position of the short circuit resistor is halved by adopting the series-parallel switching circuit which is connected by the double knives of the relay contact connection, the resistance at the position of the short circuit contact is less than or equal to 0.015 omega, the flexibility is very high, the output precision of the whole-range resistance value can be improved, and the accuracy is high. In the range of 0 to 999.9 omega, if the resolution is 0.1 omega, and the combination of hundred and ten digits obtains the resistance value output of 990 omega, the relay is completely disconnected, and the resistance deviation at the moment is the maximum deviation of the combination of hundred and ten digits, namely 10× (±0.002%) = ±0.02%). In summary, when a resistance value output of 999.9Ω is obtained, the maximum resistance deviation at this time is: 990× (±0.02%) + (±0.02 Ω) = (±0.198) +(±0.02) = ±0.218 Ω. The resistance value range is 0-999.9Ω, the resolution is 0.1Ω, and the full-range precision and accuracy are better than 0.25Ω, namely the full-range precision and accuracy are +/-0.025%. Each hundred-bit resistor unit and each ten-bit resistor unit of the series resistor group are connected in parallel by 5 resistors with the same specification and resistance deviation, the resistance deviation of each resistor is +/-0.01%, and the maximum deviation of the resistance of each resistor unit is reduced to +/-0.01%/5+/-0.002%; under the control of an external digital control device, the output resistance value is corrected according to the number of the short-circuit points, so that the resistance value of the resistor basic unit is zero resistance value or fixed resistance value, and when the resistance value of the resistor unit is fixed resistance value, the fixed resistance values of the resistor units are different, the positive and negative matching of the resistor arrangement improves the precision, and the low cost and the high precision are realized. Therefore, in the electronic circuit of the intelligent equipment, any resistance value within 2N certain ranges can be conveniently provided through the external digital control device, the digital control of the resistance value of the resistor is conveniently carried out in the application of the circuit board group, the automation is conveniently realized in the application requiring the variable resistor, and meanwhile, the resistor with adjustable high precision can be designed.
The variable resistor is accurate in output, and the given resistance value can be corrected by calculating the number of the short contacts of the relay and checking the corresponding number of the contacts of the relay by software of the singlechip. When the device outputs any resistance value of 0-999.99Ω, the hundred-bit, ten-bit, one-bit and ten-bit relay contacts are short-circuited according to the combination requirement to output the target resistance, each resistor unit combination corresponds to 1-9 selective outputs, each resistor unit combination is provided with a corresponding fixed relay contact closing combination, the number of relays on a resistor output loop can be counted according to the output of each resistance value, the accumulated total resistance value of the relay closing contacts is subtracted from the final combined output resistance value of the resistor, and thus the short-circuited contact resistance can be further reduced. In addition, the contact resistance of the relay contact at the short circuit resistance is halved through the parallel connection of the relay double knives. In order to obtain a target resistance value, i.e. less than or equal to 9 times 10 to some power of the corresponding bit, at each bit of the resistor combination, the excess resistance value needs to be shorted with a relay contact. And the relay contact short circuit redundant resistor is adopted to realize target resistance, such as resistance combination of the bit, and the relay contact short circuit combination of the bit resistance combination is adopted to realize selective output of 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9. Meanwhile, the resistance of the short-circuit part of the section is optimized, the contact resistance is halved by adopting two groups of relay contacts to be connected in parallel, the maximum resistance value of a single contact of the relay is 0.03 omega, and after the two groups of relay contacts are connected in parallel, the resistance of the short-circuit part of the contact is less than or equal to 0.015 omega, so that the short-circuit contact resistance can be reduced, and the output precision of the final resistance value is improved.
The hundred-bit series resistor group resistor units R1-R5 are alternately arranged according to positive deviation and negative deviation of the resistor values, so that the resistor value magnitude output with better accuracy is obtained; the ten-bit series resistor groups R6-R10, the unit series resistor groups R11-R15 and the ten-bit series resistor groups R16-R20 are alternately arranged with positive deviation and negative deviation of the resistance values of the R1-R5 resistor units, so that the resistance value magnitude output with better accuracy is obtained.
The positive and negative matching of each resistor combination resistor arrangement is carried out, and the resistor combination resistor is alternately arranged according to the positive deviation and the negative deviation of the resistor value, so that the resistor value magnitude output with better accuracy is obtained, the full-range precision and the accuracy of the resistor combination resistor are still considered to be +/-0.025%, and the full-range precision and the accuracy are better than 0.25Ω and are unchanged. Therefore, the actual accuracy of the resistance value on the whole circuit is improved, secondary screening and pairing are needed, and the workload is relatively small. Furthermore, the precision of the resistor is improved by connecting a plurality of resistors in parallel. The resistor is set to be composed of hundred-bit, ten-bit, unit and ten-bit resistors, each unit of the resistor combination unit and the ten-bit resistor unit is connected in parallel by 5 resistors with the same specification and resistance deviation, the resistance deviation of each resistor is +/-0.01 omega, and the maximum resistance deviation of each unit of the resistor is reduced to +/-0.01 omega/5= +/-0.002 omega; if the bit and tenth combination obtains a resistance value output of 9.9Ω, the relay is fully opened, and the resistance deviation at this time is the maximum deviation of the bit and tenth combination, namely 10× (±0.002 Ω) = ±0.02Ω. Each hundred-bit resistor unit and each ten-bit resistor unit of the resistor combination are connected in parallel by 5 resistors with the same specification and resistance deviation, the resistance deviation of each resistor is +/-0.01%, and the maximum deviation of the resistance of each resistor unit is reduced to +/-0.01%/5+/-0.002%; if the resistance value output of 990 omega is obtained by the hundred-bit and ten-bit combination, the relay is completely disconnected, and the resistance deviation at the moment is the maximum deviation of the hundred-bit and ten-bit combination, namely 10× (±0.002%) = ±0.02%. In summary, when a resistance value output of 999.9Ω is obtained, the maximum resistance deviation at this time is: 990× (±0.02%) + (±0.02 Ω) = (±0.198) +(±0.02) = ±0.218 Ω. The resistance value range is 0-999.9Ω, the resolution is 0.1Ω, and the full-range precision and accuracy are better than 0.25Ω, namely the full-range precision and accuracy are +/-0.025%. This allows a higher cost resistor to be achieved with a lower cost resistor.
The anti-interference capability is strong. The invention adopts RS485 to communicate with the upper computer. One path of asynchronous and full duplex serial port of the singlechip is electrically connected with an RS485 bus of the upper computer, the upper computer addresses the resistor given device through the RS485 bus, and the required electricity is achieved through series combination of resistors, so that the anti-interference capability is strong. The resistance of the analog resistance signal of the resistance sensor is generally 0-999.9Ω, the resolution is 0.1 Ω, and the full-range precision and accuracy are better than 0.25Ω, namely the full-range precision and accuracy are +/-0.025%.
Drawings
FIG. 1 is a schematic circuit diagram of a resistor combination according to the method of the present invention for combining a given output resistance value in series-parallel.
FIG. 2 is a schematic circuit diagram of an alternative embodiment of the typical correspondence of the resistance values of FIG. 1.
FIG. 3 is a diagram of a single chip communication, control and drive circuit for a resistor card.
Fig. 4 is a schematic circuit diagram of a variable resistor single chip system.
FIG. 5 is a schematic diagram of the differential series resistances with the differential value of 100 Ω and the range of 0 Ω to 900 Ω, formed by the combination of hundred resistors.
The invention will be further described with reference to the drawings and examples, without thereby restricting the invention to the scope of the examples.
Detailed Description
See fig. 1. According to the invention, at least 4 resistor units with 200 omega and 1 resistor unit with 100 omega are adopted at intervals of 100 omega, and are connected in series to form a hundred-bit resistor combination body with an equidifferential series resistance value with the range of an access circuit of 0 omega-900 omega; the ten-bit resistor combination with the interval value of 10Ω, at least 4 resistor units of 20Ω and 1 resistor unit of 10Ω and the series connection form an arithmetic series resistance with the range of 0 Ω -90Ω; at least 4 resistance units with interval value of 1 omega and at least 4 resistance units with interval value of 2 omega and 1 are connected in series to form an electric bit resistance assembly with an arithmetic series resistance value with the range of 0 omega-9 omega of an access circuit; at least 4 resistor units with interval value of 0.1 omega and 1 resistor unit with interval value of 0.2 omega are connected in series to form a ten-bit resistor combination with an equidifferent number series resistance value with the range of 0 omega-0.9 omega; thus, the maximum values of hundred-bit, ten-bit, unit-bit and ten-bit resistor combinations are added, the maximum value is 900+90+9+0.9=999.9Ω, the minimum resolution is 0.1Ω, and a double-knife double-linked switch switching relay which is connected in parallel at intervals on a series line is arranged between each two adjacent series resistors, the number of short contacts of the relay on the resistance output loop is counted by the variable resistor singlechip system, and the accumulated total resistance value of the closed contacts of the relay is subtracted from the combined output resistance value. The series structure of the hundred-bit series resistor group, the ten-bit series resistor group, the unit series resistor group and the ten-bit series resistor group forms an output resistor. The hundred-bit series resistor group is a basic framework for outputting the resistance value of the resistor card, wherein the series resistor group is formed by connecting 4 resistance units of 200 omega and 1 resistance units of R1 to R5 of 100 omega in series to form 0 omega to 900 omega (the interval value is 100 omega); the ten-group series resistor group is a basic framework for outputting the resistance value of the resistor card, wherein 4R 11-R15 series resistor groups with the spacing value of 10 omega and with the spacing value of 10 omega are formed by connecting 4R 6-R10 resistor units with the spacing value of 20 omega and 1R 6-R10 resistor units with the spacing value of 10 omega in series; the group series resistor is a basic framework for outputting the resistance value of the resistor card, wherein the series resistor group comprises 4 resistor units with the spacing value of 1 omega and the spacing value of 0 omega-9 omega, which are formed by connecting 2 omega and 1 ohm in series; the ten-bit series resistor is a basic framework for outputting the resistance value of the resistor card, and the series resistor group is formed by connecting 4R 16-R20 resistor units with the spacing value of 0.2 omega and 1R 16-R20 resistor units with the spacing value of 0.1 omega in series to form 0 omega-0.9 omega. And adding the maximum values of the resistances of the hundred-bit, ten-bit, one-bit and ten-bit series resistor groups to 900+90+9+0.9=999.9, thus forming the resistor given device with the maximum value of 999.9Ω and the minimum resolution of 0.1Ω.
The combination modes of each hundred, ten, unit and ten bits are the same, such as the combination of hundred resistors. The hundred-bit resistor combination is a resistor combination of 0 omega-900 omega (interval value is 100 omega) formed by connecting 4 resistor units of 200 omega and 1 resistor unit of 100 omega in series; and when the relay contact on the 100 omega resistance unit on the hundred digits is disconnected, the 100 omega resistance unit is connected into the series structure to form an output resistor, and when the relay contact on the 100 omega resistance unit is closed, the 100 omega resistance unit is equivalent to 0 omega of short circuit, and the 100 omega is not connected into the series structure to form the output resistor. The relay contacts on the circuit formed by the other 4 200 omega on the hundred bits are disconnected or connected, so that the corresponding 200 omega resistor units can be connected into or separated from the series structure to form an output resistor; the combination of the opening and closing of the relay contacts of the plurality of groups can obtain the resistor combination of 0 omega-900 omega (interval value is 100 omega), or the equidifference series resistance values with 100 omega difference and 0 omega-900 omega range are formed.
When the contacts K31B, K31C, K B, K32C, K21B, K21 823 22B, K22C, K11B, K C, K12B, K12 6712C, K01B, K01C, K02B, K02C of the relay connected across the resistors R5, R10, R15 and R20 are connected, the theoretical value of the resistance output by RHI and RLo is the minimum value of 0Ω.
When the contacts of the relay connected across the resistor are all open, the resistance value output by the two ends of RHI and RLo is the maximum value 999.9Ω.
When the contacts of the relay connected across the resistor are selectively turned off or on as required, the resistance value output by the two ends of RHI and RLo is a certain resistance value of 0-999.9Ω, and the minimum variation of the resistance is 0.1Ω.
Contacts of the relay bridged on the resistor are all connected by double knives, so that the contact resistance of the relay contact at the short-circuit resistor is halved, and the resistance at the short-circuit position of the contact is less than or equal to 0.015 omega, so that the output precision of the final resistance value is improved.
The resistors with the deviation of the resistance values are all shelf products, and only qualified products of resistor manufacturers are needed.
In order to obtain the target resistance value, the redundant resistance value needs to be short-circuited by adopting a relay contact, and the target resistance is realized by adopting the relay contact to short-circuit redundant resistance at each bit of the series resistance group, namely, to the power of less than or equal to 9 times 10 corresponding bits, for example, the series resistance group of the bit is realized by adopting the relay contact short-circuit combination of the series resistance group of the bit, and the selection output of 1 omega or 2 omega or 3 omega or 4 omega or 5 omega or 6 omega or 7 omega or 8 omega or 9 omega is realized. Meanwhile, the resistance of the short-circuit part of the section is optimized, the contact resistance is halved by adopting two groups of relay contacts to be connected in parallel, the maximum resistance value of a single contact of the relay is 0.03 omega, and after the two groups of relay contacts are connected in parallel, the resistance of the short-circuit part of the contact is less than or equal to 0.015 omega, so that the output precision of the final resistance value is improved.
The resistor is given to be composed of hundred-bit series resistor groups, ten-bit series resistor groups, bit series resistor groups and ten-bit series resistor groups, each bit resistor unit of the series resistor groups and the ten-bit series resistor groups is connected in parallel by 5 resistors with the same specification and resistance deviation, the resistance deviation of each resistor is +/-0.01 omega, and the maximum deviation of the resistance of each resistor unit is reduced to +/-0.01 omega/5+/-0.002 omega; if the series resistor group combination of the bit and the tenth bit obtains the resistance value output of 9.9Ω, the relay is fully opened, and the resistance deviation at the moment is the maximum deviation of the series resistor group combination of the bit and the tenth bit, namely 10× (±0.002 Ω) = ±0.02Ω.
The variable resistor is controlled by a singlechip system, and the singlechip calculates the number of short contacts of the relay through software to correct the given resistance value. When outputting any resistance value of 0-999.9Ω, the hundred-position relay set, the ten-position relay set, the unit relay set and the ten-position relayThe contact points of the device are used for carrying out short-circuit resistance according to the combination requirement to achieve the output of target resistance, each resistance unit combination corresponds to the selection output of 1-9 weight bits, and the hundred-bit relay group outputs (1-9) multiplied by 10 2 Omega resistance, ten-bit relay group output (1-9) x 10 1 Resistance of omega, output of unit relay group (1-9) ×10 0 Omega resistance, ten-bit relay group output (1-9) x 10 -1 Resistance of Ω. The closed combination corresponding to the fixed relay contacts is arranged respectively, the number of the relays on the resistor output loop can be counted by outputting the resistance value of each time, and the accumulated total resistance value of the closed contacts of the relays is subtracted from the combined output resistance value of the final resistor.
See fig. 2. In order to improve the precision, in an alternative embodiment of the typical correspondence of the resistance values of each resistance unit connected in parallel through a plurality of resistors, R1 in fig. 1 is corresponding, except that the 200Ω resistance of R1 is obtained by connecting 5 1000Ω resistors in parallel; the other resistances are also obtained by the above constitution. The resistor units R1-R10 are all RJ711 type high-precision alloy foil resistors, the combined resistance value of each resistor unit of R1-R4 is 200 omega, and each resistor unit of R1-R4 is obtained by connecting 5 resistors with 1000 omega resistance values and resistance allowable deviation +/-0.01% in parallel; the combined resistance of the R5 resistor unit is 100 omega, and is obtained by connecting 5 resistors with 500 omega resistance and allowable deviation of the resistance of +/-0.01 percent in parallel. The combined resistance value of each resistance unit of R6-R9 is 20Ω, and each resistance unit of R6-R9 is obtained by connecting 5 resistors with resistance value of 100deg.OMEGA and allowable deviation of resistance value of + -0.01% in parallel; the combined resistance of the R10 resistor unit is 10Ω, and is obtained by connecting 5 resistors with 50 Ω resistance and allowable deviation of resistance of + -0.01%.
Each of R11-R20 adopts RXJ3 precise wire-wound resistors, the combined resistance value of each of R11-R14 resistor units is 2 omega, and each of R11-R14 resistor units is obtained by connecting 5 resistors with the resistance value of 10 omega and the allowable deviation of the resistance value of +/-0.01 omega in parallel; the combined resistance of the R15 resistor unit is 1 omega, and is obtained by connecting 5 resistors with the resistance of 5 omega and the allowable deviation of the resistance of +/-0.01 omega in parallel. The combined resistance value of each resistance unit of R16-R19 is 0.2 omega, and each resistance unit of R16-R19 is obtained by connecting 5 resistors with resistance value of 1 omega and allowable deviation of resistance value of +/-0.01 omega in parallel; the combined resistance of the R20 resistor unit is 0.1 omega, and is obtained by connecting 5 resistors with the resistance of 0.5 omega and the allowable deviation of the resistance of +/-0.01 omega in parallel.
See fig. 3. The singlechip controls the given resistance output of the variable resistor, wherein the singlechip D1 can adopt a singlechip with the model number of C8051F310, the low-power-consumption transceiver D2 can adopt a low-power-consumption transceiver with the model number of MAX485ESA, the triggers D3, D5, D7 and D9 can adopt a trigger with the model number of 74HC273, and the drivers D4, D6, D8 and D10 can adopt drivers with the model number of MC1413P (BP). One path of asynchronous and full duplex serial port UART0 of the singlechip outputs an RS485 signal, the RS485 signal is output through a low-power-consumption transceiver D2 by a control line P0.4 and a control line P0.5 of the singlechip D1 and a signal direction control end P1.7, the low-power-consumption transceiver D2 is connected with an upper computer by an output end parallel resistor R21, and the RS485 signal is sent into the upper computer. The singlechip D1 receives a target resistance value input instruction of the upper computer through the low-power-consumption transceiver D2. Control lines P1.2, P1.3, P1.4 and P1.5 of the singlechip D1 are respectively connected with clock ends CLK of the triggers D3, D5, D7 and D9, parallel lines P2 of the singlechip are respectively P2.0, P2.1, P2.2, P2.3, P2.4, P2.5, P2.6 and P2.7, and are simultaneously connected with 8-bit input ends of the triggers D3, D5, D7 and D9, and 5-bit output lines of the triggers D3, D5, D7 and D9 are respectively connected with 5-bit input ends of the drivers D4, D6, D8 and D10. When the 5-bit output ends of the drivers D4, D6, D8 and D10 respectively have low level, the relay connected with the low level forms a circuit loop to enable the relay to be electrified, the relay acts, the normally open contact corresponding to the relay acts, the relay acts to enable the contact to be connected, and the resistance unit controlled by the relay contact in FIG. 1 is ensured to be connected or withdrawn from the output resistance loop. If the 1 pin of D4 is high, the 16 pin of D4 is reversely low, the low level is connected with the negative end of the K31A relay, the positive end of the relay is positively charged with +12V, at the moment, the relay is electrically operated, normally open contacts K31B and K31C on the relay are closed, a resistor R5 related to the K31B and the K31C is short-circuited, and the resistance value of R5, namely 100 omega is not connected into the whole resistor loop. Whether other resistance values on the line loop are connected to the entire resistance loop also depends on whether the normally open contact associated with its neighbors is on or off.
The hundred-bit relay group is controlled by a K31A, K32A, K33A, K34A, K A relay, a K31A relay controls the on or off of a K31B, K C contact, likewise, a K32A relay controls the on or off of a K32 3832C contact, a K33A relay controls the on or off of a K33B, K C contact, a K34A relay controls the on or off of a K34B, K34C contact, and a K35A relay controls the on or off of a K35B, K C contact.
The ten-position relay group is controlled by a K21A, K22A, K23A, K24A, K A relay, a K21A relay controls the on or off of a K21B, K C contact, likewise, a K22A relay controls the on or off of a K22B, K C contact, a K23A relay controls the on or off of a K23B, K C contact, a K24A relay controls the on or off of a K24B, K24C contact, and a K25A relay controls the on or off of a K25B, K C contact.
The unit relay group is controlled by a K11A, K12A, K13A, K14A, K A relay, a K11A relay controls the on or off of a K11B, K C contact, likewise, a K12A relay controls the on or off of a K12B, K C contact, a K13A relay controls the on or off of a K13B, K13C contact, a K14A relay controls the on or off of a K14B, K C contact, and a K15A relay controls the on or off of a K15B, K C contact.
The ten-bit relay group is controlled by a K01A, K02A, K03A, K04A, K A relay, the K01A relay controls the on or off of a K01B, K01C contact, the K02A relay controls the on or off of a K02B, K C contact, the K03A relay controls the on or off of a K03B, K03C contact, the K04A relay controls the on or off of a K04B, K04C contact, and the K05A relay controls the on or off of a K05B, K C contact.
When the variable resistor singlechip system controls to work, when the singlechip D1 receives a target resistance value input instruction of an upper computer through the low-power-consumption transceiver D2, hundred-bit, ten-bit, each-bit and ten-bit control instructions are formed through the operation of the singlechip, the hundred-bit, ten-bit, each-bit and ten-bit control instructions respectively enter the triggers D3, D5, D7 and D9, and data of the triggers D3, D5, D7 and D9 enable corresponding contacts of the relay to be respectively closed through the drivers D4, D6, D8 and D10, so that required resistance value output is obtained. The whole time of receiving, processing and outputting is completed within 0.3s, wherein the motion of the relay is stably completed within 0.1 s.
See fig. 4. The control circuit of the singlechip receives a control instruction output by the resistance value of the upper computer body, decomposes the control instruction to form control instructions corresponding to hundred-bit, ten-bit, each-bit and ten-bit resistance values, converts the control instructions into data and sends the data to the latches D3, D5, D7 and D9, the data of the latches D3, D5, D7 and D9 pass through the drivers D4, D6, D8 and D10 to further determine whether the corresponding relays K31A, K32A, K33 38349 34 3995A, K21A, K22A, K3724A, K25A, K11A, K12A, K A, K14A, K15A, K01 38332 02A, K03A, K04A, K A are electrified, and the relays of the circuit loop are electrified to close or open the corresponding normally open contacts of the circuit loop, so that the finally output resistance value is determined.
See fig. 5. The hundred-bit resistors are combined to form a schematic diagram of the equi-differential series resistance with the difference value of 100 omega and the measuring range of 0 omega-900 omega. The figure is representative of a ten-bit resistor combination, a unit resistor combination, and a ten-bit resistor combination.
In the figure, the key relay contacts for each set of resistance value outputs are:
the normally open contact of K31B, K31C, K B, K C is closed, and the output resistance is 0Ω;
the normally open contact of K31B, K C is opened, the normally open contact of K32B, K C is closed, and the output resistance is 100deg.C;
the normally open contact of K31B, K31C, K B, K C is closed, the normally open contact of K32B, K C is opened, and the output resistance is 200Ω;
the normally open contact of K31B, K31C, K B, K C is opened, the normally open contact of K33B, K C is closed, and the output resistance is 300 omega;
the normally open contact of K31B, K31C, K34B, K C is closed, the normally open contact of K32B, K32C, K33B, K C is opened, and the output resistance is 400 omega;
the normally open contact of K31B, K31C, K32B, K32C, K33B, K C is opened, the normally open contact of K34B, K34C is closed, and the output resistance is 500 omega;
the normally open contact of K31B, K31C, K35B, K C is closed, the normally open contact of K32B, K C, K33B, K33C, K B, K C is opened, and the output resistance is 600Ω;
the normally open contact of K31B, K C, K32B, K32C, K B, K33C, K34B, K C is opened, the normally open contact of K35B, K C is closed, and the output resistance is 700 omega;
the normally open contact of K31B, K C is closed, the normally open contact of K32B, K32 38328 5633B, K C, K34B, K34C, K35B, K35C is opened, and the output resistance is 800 omega;
the normally open contact of K31B, K31C, K32C, K B, K33 38326 34B, K6783C, K35 3735C is opened, and the output resistance is 900 omega.
The present invention is not limited to the above-described embodiments, and any other various forms of products may be obtained by any person in the light of the present invention, but various substitutions and alterations may be made without departing from the spirit and scope of the present invention.

Claims (7)

1. A method for combining a given output resistance value in series-parallel, characterized by: the resistor is set to be composed of hundred-bit, ten-bit, unit and ten-bit resistors, each unit of the resistor combination unit and the ten-bit resistor unit is connected in parallel by 5 resistors with the same specification and resistance deviation, and the resistance deviation of each resistor is +/-0.01 omega; at least 4 resistor units with 200 omega and 1 resistor unit with 100 omega are adopted at intervals of 100 omega to form a hundred bit resistor combination body with the range of an access circuit ranging from 0 omega to 900 omega in series; the ten-bit resistor combination with the interval value of 10Ω, at least 4 resistor units of 20Ω and 1 resistor unit of 10Ω and the series connection form an arithmetic series resistance with the range of 0 Ω -90Ω; at least 4 resistance units with interval value of 1 omega and at least 4 resistance units with interval value of 2 omega and 1 are connected in series to form an electric bit resistance assembly with an arithmetic series resistance value with the range of 0 omega-9 omega of an access circuit; at least 4 resistor units with interval value of 0.1 omega and 1 resistor unit with interval value of 0.2 omega are connected in series to form a ten-bit resistor combination with an equidifferent number series resistance value with the range of 0 omega-0.9 omega; the maximum values of the hundred-bit, ten-bit, unit-bit and ten-bit resistor combinations are added, the maximum value is 900+90+9+0.9=999.9Ω, the minimum resolution is 0.1Ω, a double-knife duplex switch switching-on relay which is connected in parallel at intervals on a serial line is arranged between each two adjacent serial resistors, so that the closed contact resistance of a short-circuit parallel resistor R contact is halved, the selection output of 1-9 is correspondingly realized, the output of each resistor value is counted by a variable resistor singlechip system, the number of short-circuit points of the relay on a resistor output loop is counted, and the accumulated total resistance value of the closed contact of the relay is subtracted from the combined output resistance value; the variable resistor is controlled by a singlechip system, and the singlechip calculates the number of short contacts of the relay through software to correct the given resistance value; when any resistance value of 0-999.9Ω is output, the hundred-bit relay group, the ten-bit relay group and the unit relay group are short-circuited according to the combination requirement, the resistor is short-circuited to reach the output of a target resistor, each resistor unit combination corresponds to the selected output of 1-9 weight bits, the hundred-bit relay group outputs the resistor of (1-9) x 10 < 2 >, the ten-bit relay group outputs the resistor of (1-9) x 10 < 1 >, the unit relay group outputs the resistor of (1-9) x 10 < 0 >, the ten-bit relay group outputs the resistor of (1-9) x 10 < 1 >, and the closed combination corresponding to the fixed relay contacts is arranged, the output of each resistor value counts how many relays on a resistor output loop are in a closed state, and the combined output resistance value of the final resistor subtracts the accumulated total resistance value of the closed contacts of the relays;
the single chip microcomputer controls the given resistance value output of the variable resistor, one path of asynchronous and full duplex serial port UART0 of the single chip microcomputer outputs an RS485 signal, the RS485 signal is output through a low-power consumption transceiver D2 by a control line P0.4 and a P0.5 port of the single chip microcomputer D1 and a signal direction control end P1.7, the low-power consumption transceiver D2 is connected with an upper computer through an output end parallel resistor R21, and the RS485 signal is sent to the upper computer;
the singlechip D1 receives a target resistance value input instruction of the upper computer through the low-power-consumption transceiver D2, when low levels appear at the respective 5-bit output ends of the driver, the relay connected with the low levels forms a circuit loop to enable the relay to be electrified, the relay acts, the normally open contact corresponding to the relay acts, the relay acts to enable the contact to be connected, and the relay contact control resistance unit is connected with or withdrawn from the output resistance loop.
2. The method for combining a given output resistance value in series-parallel as recited in claim 1, wherein: the hundred-bit resistor combination is a resistor combination of 0 omega-900 omega formed by connecting 4 resistor units of 200 omega and 1 resistor unit of 100 omega in series; and when the relay contact on the 100 omega resistor unit on the hundred digits is disconnected, the 100 omega resistor unit is connected into the series structure to form an output resistor.
3. The method for combining a given output resistance value in series-parallel as recited in claim 2, wherein: if the relay contact on the resistance unit of 100 omega is closed, the resistance unit of 100 omega is equivalent to 0 omega of short circuit, and the output resistor is formed by the 100 omega of non-connected series structure.
4. A method of combining a given output resistance value in series-parallel as recited in claim 3, wherein: switching off or switching on relay contacts on a circuit formed by 4 200 omega on hundred bits, and switching on or switching off corresponding 200 omega resistance units from a series structure to form an output resistor; the multiple sets of relay contacts are turned off or on to obtain resistor combination of 0 to 900 ohm or the differential series resistance with 100 ohm difference and 0 to 900 ohm range.
5. The method for combining a given output resistance value in series-parallel as recited in claim 1, wherein: when the contacts K31B, K31C, K B, K32C, K21B, K21 823 22B, K22C, K11B, K C, K12B, K12 6712C, K01B, K01C, K02B, K02C of the relay connected across the resistors R5, R10, R15 and R20 are connected, the theoretical value of the resistance values output by the RHI and the two ends of the RLo is the minimum value of 0 omega; when the contacts of the relay connected across the resistor are all open, the resistance value output by the two ends of RHI and RLo is the maximum value 999.9Ω.
6. The method for combining a given output resistance value in series-parallel as recited in claim 1, wherein: when the singlechip D1 receives a target resistance value input instruction of the upper computer through the low-power-consumption transceiver D2, hundred-bit, ten-bit, each-bit and ten-bit control instructions are formed respectively through operation of the singlechip, the hundred-bit, ten-bit, each-bit and ten-bit control instructions enter the triggers D3, D5, D7 and D9 respectively, data of the triggers D3, D5, D7 and D9 are obtained, and corresponding contacts of the relay are closed respectively through the drivers D4, D6, D8 and D10, so that required resistance value output is obtained.
7. The method for combining a given output resistance value in series-parallel as recited in claim 1, wherein: the control circuit of the singlechip receives a control instruction output by the resistance value of the upper computer body, decomposes the control instruction to form control instructions corresponding to hundred-bit, ten-bit, each-bit and ten-bit resistance values, converts the control instructions into data and sends the data to the latches D3, D5, D7 and D9, the data of the latches D3, D5, D7 and D9 pass through the drivers D4, D6, D8 and D10 to further determine whether the corresponding relays K31A, K32A, K33 38349 34 3995A, K21A, K22A, K23A, K4A, K25A, K11A, K12A, K A, K14A, K15A, K01 38332 02A, K02 4203A, K04A, K A are electrified, and the relays forming the circuit loop are electrified to close the corresponding normally open contacts, and the series of normally open contacts are closed or opened to determine the finally output resistance value.
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