SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a resistance measurement control circuit aims at solving the problem that resistance measurement range is low, resolution ratio is low among the prior art.
The utility model discloses a realize like this, the utility model provides a resistance measurement control circuit, include:
the device comprises a resistance voltage division module, a voltage following module, a voltage sampling module, a signal filtering module, a signal amplifying module and an analog-to-digital conversion module;
the resistance voltage division module is electrically connected with the voltage sampling module through the voltage following module, the resistance voltage division module is used for providing a voltage signal for the voltage sampling module, and the voltage following module is used for controlling the current in the resistance voltage division module to only flow to the voltage sampling module so as to avoid the influence of the voltage following module and the voltage sampling module on the resistance voltage division module;
the voltage sampling module, the signal filtering module, the signal amplifying module and the analog-to-digital conversion module are sequentially and electrically connected, and the voltage sampling module is also electrically connected with the resistor to be tested and the analog-to-digital conversion module respectively;
the voltage sampling module is used for applying the voltage signal to the resistor to be tested to generate a sampling signal, transmitting the sampling signal to the signal filtering module and transmitting the voltage signal to the analog-to-digital conversion module;
the signal filtering module is used for eliminating interference signals in the sampling signals to generate the filtered sampling signals;
the signal amplification module is used for amplifying the filtered sampling signal to generate an amplified signal;
the analog-to-digital conversion module is used for receiving the amplified signal and the voltage signal and performing analog-to-digital conversion on the amplified signal and the voltage signal.
In one embodiment, the resistance voltage division module comprises a reference voltage chip and a plurality of voltage division resistors;
the reference voltage chip is connected with the plurality of divider resistors in series, and is used for applying a stable voltage signal to the plurality of divider resistors so as to form different voltage signals on the plurality of divider resistors.
In one embodiment, the voltage follower module comprises a voltage follower circuit, a plurality of first input lines, a plurality of first output lines and a first switch structure;
the voltage follower circuit passes through a plurality of first input lines respectively with a plurality of divider resistance electricity are connected, the voltage follower circuit passes through a plurality of first output lines respectively with voltage sampling module electricity is connected, first switch structure is including setting up a plurality of switches on the first output line, with to voltage sampling module exports different voltages.
In one embodiment, the voltage sampling module comprises a plurality of sampling resistors, a plurality of second input lines, a second output line and a second switch structure;
the sampling resistors are respectively connected with the first output lines, and the sampling resistors are respectively connected with the resistors to be tested in series;
the second switch structure comprises a plurality of switches arranged on the second input circuit, and is used for controlling and connecting the resistance to be tested in series with the sampling resistor and the analog-to-digital conversion module, so that the analog-to-digital conversion module is right on the sampling resistor and the voltage signal is read.
In one embodiment, the signal filtering module comprises a second-order filtering circuit and a low-pass filtering circuit;
the second-order filter circuit is electrically connected with the sampling resistors and the resistor to be tested, and is used for eliminating the interference of low-frequency signals in the sampling signals;
the low-pass filter circuit is electrically connected with the second-order filter circuit and is used for eliminating the interference of high-frequency signals in the sampling signals.
In one embodiment, the signal amplification module includes a plurality of operational amplification circuits, a plurality of third input lines, a plurality of third output lines, and a third switch structure;
the plurality of operational amplification circuits are electrically connected with the signal filtering module through the plurality of third input lines respectively, and the third switch structure comprises switches arranged on the plurality of third input lines and is used for controlling the filtered sampling signals to be transmitted to the plurality of operational amplification circuits;
the operational amplification circuits are respectively connected with the analog-to-digital conversion module through the third output lines and are used for transmitting the amplified signals to the analog-to-digital conversion module.
In one embodiment, the analog-to-digital conversion module comprises an ADC input signal selection module, an ADC module and an MCU module;
the ADC input signal selection module is respectively electrically connected with the plurality of operational amplification circuits and is used for receiving the amplified signals;
the ADC input signal selection module is connected with the second output line and used for receiving the voltage signal;
the ADC input signal selection module is electrically connected with the ADC module, the ADC input signal selection module is used for transmitting the voltage signal and the amplified signal to the ADC module, the MCU module is electrically connected with the ADC module, and the MCU module is used for controlling the ADC module to perform analog-to-digital conversion on the voltage signal and the amplified signal.
In one embodiment, the system further comprises a data storage module;
the data storage module is electrically connected with the MCU module and is used for reading and writing data;
the data storage module is an EEPROM.
In one embodiment, the device further comprises a serial port communication module;
the serial port communication module is electrically connected with the MCU module and is provided with a reserved interface for connecting a computer so as to realize the connection between the MCU module and the computer;
the serial port communication module is MAX232.
The utility model provides a resistance measurement control circuit has following beneficial effect:
1. the utility model provides a be provided with a plurality of divider resistance that the resistance value is different among the resistance divider module, can export the voltage signal who corresponds different ranges, the utility model provides a voltage sampling module is provided with a plurality of sampling resistor that the resistance value is different, can establish ties with the resistance to be measured of different resistances, can measure the resistance to be measured of different resistances effectively, has widened the measuring range, has promoted measurement accuracy, has solved the problem that resistance measurement range is low among the prior art, resolution ratio is low.
2. The utility model discloses in be provided with signal filtering module and signal amplification module for carry out signal filtering and signal amplification to the sampled signal, with the accurate nature that promotes the sampled signal, thereby promote resistance measurement's precision.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present invention, it should be understood that if there are the terms "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of the description, but it is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore the terms describing the positional relationship in the drawings are only for illustrative purposes and are not to be construed as limitations of the present patent, and those skilled in the art can understand the specific meanings of the terms according to specific situations.
The following describes the implementation of the present invention in detail with reference to specific embodiments.
Referring to fig. 1, a preferred embodiment of the present invention is provided.
The utility model provides a resistance measurement control circuit, include:
the device comprises a resistance voltage division module 1, a voltage following module 2, a voltage sampling module 3, a signal filtering module 4, a signal amplifying module 5 and an analog-to-digital conversion module 6.
Specifically, resistance voltage division module 1 is connected with voltage sampling module 3 electricity through voltage following module 2, and resistance voltage division module 1 is used for providing voltage signal to voltage sampling module 3, and voltage following module 2 has great input impedance for the electric current in control resistance voltage division module 1 only flows to voltage sampling module 3, in order to avoid voltage following module 2 and voltage sampling module 3 to resistance voltage division module 1's influence.
It should be noted that, the voltage sampling module 3 can be electrically connected with the resistor 7 to be measured, and receive the voltage signal provided by the resistor voltage dividing module 1, so as to implement the detection of the resistance value of the resistor 7 to be measured, and in this process, if the resistance value of the resistor 7 to be measured is too small, the resistor connected in series with the resistor is smaller, so as to cause the measured data to be inaccurate, therefore, a voltage following module 2 is required, so that the current only flows to the voltage sampling module 3, so as to avoid the influence of the voltage following module 2 and the voltage sampling module 3 on the resistor voltage dividing module 1 to cause the inaccurate measurement.
Specifically, the voltage sampling module 3, the signal filtering module 4, the signal amplifying module 5 and the analog-to-digital conversion module 6 are electrically connected in sequence, and the voltage sampling module 3 is further electrically connected with the resistor to be tested 7 and the analog-to-digital conversion module 6 respectively.
It should be noted that the voltage sampling module 3 receives a voltage signal and applies the voltage signal to the resistor 7 to be tested, so as to form a sampling signal, the sampling signal passes through the signal filtering module 4 and the signal amplifying module 5 to the analog-to-digital conversion module 6, and the voltage signal is directly transmitted to the analog-to-digital conversion module 6.
It can be understood that, signal filtering module 4 is arranged in eliminating the interference signal among the sampled signal, in order to generate the sampled signal after filtering, signal amplification module 5 is used for enlarging the sampled signal after filtering, after signal amplification, analog-to-digital conversion module 6 can read the resolution ratio of signal and will be higher, resistance measurement accuracy can be higher, consequently, insert signal filtering module 4 and signal amplification module 5 between voltage sampling module 3 and analog-to-digital conversion module 6, can ensure that the sampled signal is more clear high-efficient, promote measurement accuracy.
It should be noted that the voltage sampling module 3 itself has a plurality of sampling resistors 31, the sampling resistors 31 are connected with the resistor 7 to be measured, and a sampling signal is generated under the action of the voltage signal, and since the voltage signal and the sampling resistors 31 are known values, the analog-to-digital conversion module 6 can obtain the resistance value of the resistor 7 to be measured by analog-to-digital conversion and formula calculation after receiving the voltage signal and the sampling signal.
Referring to fig. 2, rx is a resistor to be measured 7,R which is a precision resistor, vx is a fixed voltage, and Vr is a voltage at two ends of Rx, and Rx/(R + Rx) = Vr/Vx can be known from the voltage division principle of the series circuit.
It can be understood that, because there is only one fixed resistor R in the loop, if R is selected to be smaller, when the resistor 7 to be measured is smaller, the resistor Rx is easily burned out due to a larger current in the series circuit formed by R and Rx, if R is selected to be larger, when the resistor 7 to be measured is smaller, the change of the resistance of the resistor 7 to be measured does not allow Vr to have a larger change, and at this time, the circuit has a poorer reading resolution, and the resistor measurement accuracy is lower.
More specifically, the utility model provides a can export multiple different voltage signal among the resistance voltage divider module 1, correspond different ranges to adapt to the resistance 7 that awaits measuring of different scopes, resistance value range broad that can the measuring resistance 7 that awaits measuring, and the precision is higher.
More specifically, the utility model provides an operational amplification circuit 51 that has different multiples in the operational amplification module makes the sampling signal of the maximum resistance value that corresponds every range all be close after operational amplification circuit 51 enlargies with analog-to-digital conversion module 6's reference voltage value, makes the resolution ratio of analog-to-digital conversion result higher, measures more accurately.
The utility model provides a resistance measurement control circuit has following beneficial effect:
1. the utility model provides a be provided with a plurality of divider resistance 12 that the resistance value is different among the resistance divider module 1, can export the voltage signal who corresponds different ranges, the utility model provides a voltage sampling module 3 is provided with a plurality of sampling resistor 31 that the resistance value is different, can establish ties with the resistance 7 that awaits measuring of different resistances, can measure the resistance 7 that awaits measuring of different resistances effectively, has widened the measurement range, has promoted measurement accuracy, has solved the problem that resistance measurement range is low among the prior art, resolution ratio is low.
2. The utility model discloses in be provided with signal filtering module 4 and signal amplification module 5 for carry out signal filtering and signal amplification to sampling signal, with the precision that promotes sampling signal, thereby promote resistance measurement's precision.
In some embodiments, the resistor divider module 1 includes a reference voltage chip 11 and a number of divider resistors 12.
Specifically, the reference voltage chip 11 is connected in series with the voltage dividing resistors 12, and the reference voltage chip 11 is configured to apply a stable voltage signal with high precision to the voltage dividing resistors 12.
It is understood that the resistance values of the voltage dividing resistors 12 are different, and thus the voltage signals formed at the voltage dividing resistors 12 are also different.
More specifically, the utility model discloses a measuring circuit's measuring range is 0 omega to 3M omega, in order to let the range of difference can both realize the precision measurement, divide into four ranges with measuring range, is 0 to 30 omega respectively, 30 omega to 3000 omega, 3000 omega to 300K omega, 300K omega to 3M omega.
It will be appreciated that each range corresponds to a line to which the voltage follower module 2 is connected.
In some embodiments, the voltage follower module 2 comprises a voltage follower circuit 21, a number of first input lines 22, a number of first output lines 23 and a first switching structure 24.
Specifically, one end of the voltage follower circuit 21 is electrically connected to the voltage dividing resistors 12 through a plurality of first input lines 22, the other end of the voltage follower circuit 21 is electrically connected to the voltage sampling module 3 through a plurality of first output lines 23, and the first switch structure 24 includes a plurality of switches disposed on the first output lines 23.
It will be appreciated that when the switch is open, the voltage signal cannot be passed to the voltage sampling module 3, and when the switch is closed, the voltage signal can be passed to the voltage sampling module 3, so that by controlling the first switch structure 24, it is possible to control the passing of different voltage signals to the voltage sampling module 3.
In some embodiments, the voltage sampling module 3 comprises a number of sampling resistors 31, a number of second input lines 32, a second output line 33 and a second switching structure 34.
Specifically, one end of each of the sampling resistors 31 is connected to the first output lines 23, and the other end of each of the sampling resistors 31 is connected in series to the resistor 7 to be measured.
More specifically, the plurality of second input lines 32 are respectively connected with the plurality of first output lines 23, and the second output lines 33 are respectively electrically connected with the plurality of second input lines 32 and the analog-to-digital conversion module 6, it can be understood that the voltage signals will be transmitted to the analog-to-digital conversion module 6 through the first output lines 23, the second input lines 32, and the second output lines 33.
More specifically, the second switch structure 34 includes several switches disposed on the second input line 32, and it can be understood that by controlling the connection and disconnection of the second switch structure 34, the electrical connection of the sampling resistor 31 connected in series with the resistor to be tested 7 and the analog-to-digital conversion module 6 can be controlled, so that the analog-to-digital conversion module 6 can read the voltage signal on the sampling resistor 31.
In some embodiments, the signal filtering module 4 comprises a second order filtering circuit 41 and a low pass filtering circuit 42.
Specifically, the second-order filter circuit 41 is electrically connected to the sampling resistors 31 and the resistor 7 to be tested, the second-order filter circuit 41 is used for eliminating interference of low-frequency signals in the sampling signals, the low-pass filter circuit 42 is electrically connected to the second-order filter circuit 41, and the low-pass filter circuit 42 is used for eliminating interference of high-frequency signals in the sampling signals.
It can be understood that various interference signals, such as ripples and burrs, may exist in the sampled signal, and these interference signals may affect the stability of the sampled signal, so that the signal filtering module 4 needs to be disposed between the voltage sampling module 3 and the analog-to-digital conversion module 6 to eliminate interference of the interference signals, and generate a filtered sampled signal with high stability.
In some embodiments, the signal amplifying module 5 includes a plurality of operational amplifying circuits 51, a plurality of third input lines 52, a plurality of third output lines 53, and a third switch structure 54.
Specifically, the multiple operational amplifier circuits 51 are electrically connected to the signal filtering module 4 through multiple third input lines 52, respectively, and the third switch structure 54 includes switches disposed on the multiple third input lines 52 and is configured to control the filtered sampling signals to be transmitted to the multiple operational amplifier circuits 51.
It can be understood that the value intervals of the sampling signals generated by the voltage signals of different ranges are also different, so that the sampling signals need to be amplified by different amplification factors, and each operational amplifier circuit 51 corresponds to different amplification factors and can amplify the sampling signals to the reference value of the analog-to-digital conversion module 6, so as to ensure the accuracy of the measurement.
More specifically, the operational amplifier circuits 51 are connected to the analog-to-digital conversion module 6 through third output lines 53, respectively, for transmitting the amplified signals to the analog-to-digital conversion module.
In some embodiments, the analog-to-digital conversion module 6 includes an ADC input signal selection module 61, an ADC module 62, and an MCU module 63.
Specifically, the ADC input signal selection module 61 is electrically connected to the operational amplification circuits 51, respectively, for receiving the amplified signal, and the ADC input signal selection module 61 is further connected to the second output line 33 for receiving the voltage signal, it can be understood that the ADC input signal selection module 61 transmits the amplified signal and the voltage signal to the ADC module 62 after receiving the amplified signal and the voltage signal.
More specifically, the ADC input signal selection module 61 may receive signals of the operational amplifier circuits 51, that is, the ADC input signal selection module 61 may transmit amplified signals corresponding to different ranges to the ADC module 62, so as to implement measurement under different ranges, thereby improving the accuracy of measurement.
More specifically, the ADC input signal selection module 61 is electrically connected to the ADC module 62, the ADC input signal selection module 61 is configured to transmit the voltage signal and the amplified signal to the ADC module 62, and the ADC module 62 is configured to perform analog-to-digital conversion on the voltage signal and the amplified signal;
more specifically, the MCU module 63 is electrically connected to the ADC module 62, and the MCU module 63 is configured to control the ADC module 62 to perform analog-to-digital conversion on the voltage signal and the amplified signal.
In some embodiments, a data storage module 8 is also included.
Specifically, the data storage module 8 is electrically connected to the MCU module 63 for data reading and writing.
More specifically, the present invention provides a data storage module 8 which is an EEPROM.
In some embodiments, a serial communication module 9 is also included.
Specifically, the serial communication module 9 is electrically connected to the MCU module 63, the serial communication module 9 has a reserved interface for connecting to a computer, so as to connect the MCU module 63 to the computer, and it should be noted that software at the computer end can send different instructions to the MCU module 63 through a serial port, so as to control each flow in the circuit.
More specifically, the utility model provides a serial communication module 9 is MAX232.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.