CN213987227U - PH value measurement sensor module - Google Patents
PH value measurement sensor module Download PDFInfo
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- CN213987227U CN213987227U CN202023264924.2U CN202023264924U CN213987227U CN 213987227 U CN213987227 U CN 213987227U CN 202023264924 U CN202023264924 U CN 202023264924U CN 213987227 U CN213987227 U CN 213987227U
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Abstract
A PH value measurement sensor module comprises a 2.5V precision power supply circuit, a signal source voltage bias circuit, a signal amplification circuit and an external interface, wherein the 2.5V precision power supply circuit provides bias voltage for the signal source voltage bias circuit, and the signal source voltage bias circuit biases the signal source voltage into positive voltage so that the PH value measurement sensor module realizes single-power-supply work; the signal amplification circuit amplifies the biased signal source voltage and outputs the amplified signal to obtain a high-precision analog voltage signal corresponding to the pH value of the solution; the PH value measuring sensor module is connected into an industrial production system through an external interface, and a singlechip in the industrial production system is used for sampling and calculating an analog voltage signal of the PH value of the solution, so that the PH value of the corresponding solution can be obtained; the utility model discloses a PH value measurement sensor module has low price, small in size, advantage that the precision is high, can replace industrial-grade PH changer, conveniently imbeds in the industrial production equipment.
Description
Technical Field
The utility model relates to a sensor data acquisition technical field, concretely relates to PH value measurement sensor module.
Background
The pH value of the solution is an important characteristic of the solution, and the pH value of the solution is indispensable to be accurately measured in certain fields of industrial production; the existing industrial PH transmitter has high precision, but is expensive and large in volume, and cannot be really embedded into industrial production equipment; the commercially available finished PH test pen has low price and small volume, but cannot be embedded into industrial production equipment due to limited precision and no interface for accessing an industrial production system; therefore, it is necessary to develop a PH value measuring sensor module which is low in cost, small in size, high in precision, and can be embedded in an industrial production system for secondary development, so as to fill up the market gap.
SUMMERY OF THE UTILITY MODEL
In order to overcome the deficiency in the background art, the utility model discloses a PH value measurement sensor module, including 2.5V precision power supply circuit, signal source voltage bias circuit, signal amplification circuit and external interface, 2.5V precision power supply circuit provides bias voltage for signal source voltage bias circuit, signal source voltage bias circuit handles signal source voltage bias to the positive voltage, makes PH value measurement sensor module realize single power supply work; the signal amplification circuit amplifies the biased signal source voltage and outputs the amplified signal to obtain a high-precision analog voltage signal corresponding to the pH value of the solution; the PH value measuring sensor module is connected into an industrial production system through an external interface, and a singlechip in the industrial production system is used for sampling and calculating the analog voltage signal of the PH value of the solution, so that the PH value of the corresponding solution can be obtained.
In order to realize the utility model aims at, the utility model adopts the following technical scheme: a PH value measurement sensor module comprises a 2.5V precision power supply circuit, a signal source voltage bias circuit and a signal amplification circuit; the 2.5V precision power supply circuit provides bias voltage for the signal source voltage bias circuit, the signal source voltage bias circuit enables the signal source voltage bias to be positive voltage, and the signal amplification circuit amplifies the biased signal source voltage; the output end of the PH sensor is provided with PH + and PH-, under normal conditions, the output end of the PH sensor outputs voltage signals with equal voltage values and opposite directions, if the output signals of the PH sensor are directly amplified, a positive power supply and a negative power supply are needed, and therefore the cost of the PH value measuring sensor module can be increased; therefore, before amplifying the output signal of the PH sensor, a 2.5V precision power circuit and a signal source voltage bias circuit are used for carrying out bias processing on the output signal of the PH sensor, so that voltage signals with the same original potential value and opposite directions are changed into unidirectional positive voltage signals, and a negative power supply is omitted; by way of further example, if a PH sensor is placed in solution, the corresponding output signal is PH-: -200mV, PH +: 200 mV; after the output signal of the PH sensor is subjected to bias processing by a signal source voltage bias circuit, the PH-bias is 300mV, and the PH + bias is 700 mV; and sending the biased PH + into a signal amplification circuit for amplification and then outputting to obtain an analog voltage signal Vi corresponding to the pH value of the solution.
Furthermore, the 2.5V precision power supply circuit adopts a controllable precision voltage-stabilizing source, the input voltage is 5.0V, and the output voltage is 2.5V; the 2.5V precision power supply circuit generates high-precision 2.5V voltage and provides bias reference voltage for the signal source voltage bias circuit.
Furthermore, the signal source voltage bias circuit and the signal amplification circuit adopt double-group self-calibration precise operational amplifiers, and the double-group self-calibration precise operational amplifier consists of two operational amplifiers, wherein one operational amplifier is used for the signal source voltage bias circuit, and the other operational amplifier is used for the signal amplification circuit;
in a signal source voltage bias circuit, 2.5V voltage of a PH value measurement sensor module is divided by resistors RP1 and R2 and then input into a positive input end of an operational amplifier; the reverse input end of the operational amplifier is connected with the negative output end PH-of the signal source, and the output end of the operational amplifier is directly connected with the reverse input end of the operational amplifier; the signal source voltage bias circuit is essentially an impedance matching circuit, and the stability of bias point voltage is kept by using the impedance characteristics of high input and low output of operational amplifier, namely the voltage of the output end PH-of the PH sensor is a constant value no matter what solution the PH sensor is put into, so that the accuracy of the output voltage of the PH value measurement sensor module is ensured;
in the signal amplifying circuit, the positive input end of the other operational amplifier is connected with the positive output end PH + of the signal source, and the output end of the operational amplifier is divided by feedback resistors R4 and R5 and then input to the reverse input end of the operational amplifier;
the working voltage of the double-group self-calibration precision operational amplifier is 5.0V.
Further, the resistor RP1 is an adjustable potentiometer, and is used for adjusting and calibrating the PH measurement sensor module; the resistor R2 is connected in parallel with a filter capacitor C1 and used for filtering high-frequency interference signals generated by a 2.5V precision power supply circuit so as to ensure the stability of bias point voltage and the precision of the output voltage of the PH value measuring sensor module.
Furthermore, the PH value measurement sensor module also comprises a power supply indicating circuit, wherein the power supply indicating circuit is directly driven by the 5.0V power supply and is used for indicating the power-on state of the 5.0V power supply of the PH value measurement sensor module; the power supply indicating circuit comprises a light emitting diode LED0, and a current limiting resistor R3 is connected in series with a light emitting diode LED 0.
Furthermore, the PH value measurement sensor module also comprises a temperature compensation circuit, wherein the temperature compensation circuit is used for measuring the ambient temperature, and the output signal of the temperature compensation circuit is input into a singlechip in an industrial production system and is used for compensating the influence of the ambient temperature on the PH value measurement result of the solution; the temperature compensation circuit comprises a digital temperature sensor, a VDD pin of the digital temperature sensor is connected with a 5.0V power supply, an I/O pin outputs a temperature measurement signal, and a GND pin is grounded; the I/O pin is connected with a pull-up resistor R6.
Further, the PH measurement sensor module further comprises a BNC connector for connecting the PH sensor.
Further, the PH value measuring sensor module is provided with two grounds of GND1 and GND 2; the power supply indicating circuit, the temperature compensating circuit and the 2.5V precise power supply circuit are connected with GND1 in common, and the signal source voltage biasing circuit and the signal amplifying circuit are connected with GND2 in common; the GND1 and the GND2 are connected through magnetic beads and zero resistance; the two grounds GND1 and GND2 are set for suppressing high-frequency interference of an industrial production system introduced by a 5.0V power supply and ensuring the accuracy of the output voltage of the PH value measuring sensor module.
Further, the PH value measurement sensor module is provided with six external interfaces VCC, GND1, GND2, PH-OUT and 2.5V, T1 and is used for being connected into an industrial production system; wherein VCC is a 5.0V power interface; GND1 is 5.0V power ground; with GND2 being the output signal voltage ground; the PH-OUT output voltage signal interface; the 2.5V is a 2.5V precision power supply circuit output voltage detection interface which is only used for detection and can not be used as a power supply of other equipment; wherein T1 is the temperature compensation circuit signal output port.
Due to the adoption of the technical scheme, the utility model discloses following beneficial effect has: the utility model discloses a PH value measurement sensor module, including 2.5V precision power supply circuit, signal source voltage bias circuit, signal amplification circuit and external interface, 2.5V precision power supply circuit provides bias voltage for signal source voltage bias circuit, signal source voltage bias circuit handles signal source voltage bias to the positive voltage, makes PH value measurement sensor module realize single power supply work; the signal amplification circuit amplifies the biased signal source voltage and outputs the amplified signal to obtain a high-precision analog voltage signal corresponding to the pH value of the solution; the PH value measuring sensor module is connected into an industrial production system through an external interface, and a singlechip in the industrial production system is used for sampling and calculating an analog voltage signal of the PH value of the solution, so that the PH value of the corresponding solution can be obtained; the utility model discloses a PH value measurement sensor module has low price, small in size, advantage that the precision is high, can replace industrial-grade PH changer, conveniently imbeds in the industrial production equipment.
Drawings
Fig. 1 is a schematic diagram of a PH measurement sensor module.
In the figure: 1. 2.5V precision power supply circuit; 2. a signal source voltage bias circuit; 3. a signal amplification circuit; 4. a power indication circuit; 5. a temperature compensation circuit; 6. BNC connector.
Detailed Description
The invention will be explained in more detail by the following examples, which disclose the invention and are intended to protect all technical improvements within the scope of the invention.
A PH value measurement sensor module comprises a 2.5V precision power supply circuit 1, a signal source voltage bias circuit 2 and a signal amplification circuit 3, wherein the 2.5V precision power supply circuit 1 provides bias voltage for the signal source voltage bias circuit 2, the signal source voltage bias circuit 2 enables the signal source voltage bias to be positive voltage, and the signal amplification circuit 3 amplifies the biased signal source voltage; the working voltage of the PH value measuring sensor module is 5.0V;
the 2.5V precision power supply circuit 1 adopts a controllable precision voltage-stabilizing source, the input voltage is 5.0V, and the output voltage is 2.5V; the signal source voltage bias circuit 2 and the signal amplifying circuit 3 adopt double-group self-calibration precise operational amplifiers, and the double-group self-calibration precise operational amplifiers consist of two operational amplifiers, wherein one operational amplifier is used for the signal source voltage bias circuit 2, and the other operational amplifier is used for the signal amplifying circuit 3; in the signal source voltage bias circuit 2, 2.5V voltage output by the 2.5V precision power circuit 1 is divided by resistors RP1 and R2 and then input to the positive input end of the operational amplifier; the reverse input end of the operational amplifier is connected with the negative output end PH-of the signal source, and the output end of the operational amplifier is directly connected with the reverse input end of the operational amplifier; in the signal amplifying circuit 3, the positive input end of the operational amplifier is connected with the positive output end PH + of the signal source, and the output end of the operational amplifier is divided by feedback resistors R4 and R5 and then input to the negative input end of the operational amplifier; the working voltage of the double-group self-calibration precision operational amplifier is 5.0V;
the resistor RP1 is an adjustable potentiometer; the resistor R2 is connected with a filter capacitor C1 in parallel;
the PH value measuring sensor module also comprises a power supply indicating circuit 4, and the power supply indicating circuit 4 is directly driven by a 5.0V power supply; the power supply indicating circuit 4 comprises a light emitting diode LED0, and a current limiting resistor R3 is connected in series with a light emitting diode LED 0;
the PH value measurement sensor module also comprises a temperature compensation circuit 5; the temperature compensation circuit 5 comprises a digital temperature sensor, a VDD pin of the digital temperature sensor is connected with a 5.0V power supply, an I/O pin outputs a temperature measurement signal, and a GND pin is grounded; the I/O pin is connected with a pull-up resistor R6;
the pH value measuring sensor module also comprises a BNC connector 6;
the PH value measurement sensor module is provided with two grounds of GND1 and GND 2; the power supply indicating circuit 4, the temperature compensating circuit 5 and the 2.5V precise power supply circuit 1 are connected with GND1 in common, and the signal source voltage bias circuit 2 and the signal amplifying circuit 3 are connected with GND2 in common;
the PH value measuring sensor module is provided with six external interfaces of VCC, GND1, GND2, PH-OUT and 2.5V, T1.
Before the PH value measurement sensor module is used, the PH value measurement sensor module needs to be calibrated, and the specific calibration method comprises the following steps: setting a PH sensor in a solution with known pH value I to obtain an analog voltage signal V1, and calibrating V1 with the known pH value I to obtain a coordinate point P1; setting the PH sensor in a solution with known pH value of II to obtain an analog voltage signal V2, and calibrating V2 and pH value II to obtain another coordinate point P2; curve fitting is carried out on two coordinate points P1 and P2, and a calculation formula of the corresponding relation between the output voltage value of the PH value measurement sensor module and the pH value of the solution is obtained; when the PH value of the solution is actually measured, the actual PH value of the solution to be measured can be calculated according to the output voltage value of the PH value measuring sensor module by using the obtained calculation formula;
when the PH value measuring sensor module is calibrated, the reasonable bias voltage of the negative output end PH-of the signal source is set by adjusting the adjustable potentiometer RP 1.
The part of the utility model not detailed is prior art.
Claims (9)
1. A PH value measurement sensor module is characterized in that: including 2.5V precision power supply circuit (1), signal source voltage bias circuit (2) and signal amplification circuit (3), 2.5V precision power supply circuit (1) provides bias voltage for signal source voltage bias circuit (2), signal source voltage bias circuit (2) make signal source voltage bias be the positive voltage, signal amplification circuit (3) enlarge the signal source voltage behind the biasing.
2. A PH measurement sensor module as claimed in claim 1, wherein: the 2.5V precision power supply circuit (1) adopts a controllable precision voltage-stabilizing source.
3. A PH measurement sensor module as claimed in claim 2, wherein: the signal source voltage bias circuit (2) and the signal amplification circuit (3) are realized by a double-set self-calibration precise operational amplifier, the double-set self-calibration precise operational amplifier comprises two operational amplifiers, one of the two operational amplifiers is used for the signal source voltage bias circuit (2), and the other operational amplifier is used for the signal amplification circuit (3);
in the signal source voltage bias circuit (2), the output voltage of the 2.5V precision power circuit (1) is divided by resistors RP1 and R2 and then input into the positive input end of an operational amplifier; the reverse input end of the operational amplifier is connected with the negative output end PH-of the signal source, and the output end of the operational amplifier is directly connected with the reverse input end of the operational amplifier;
in the signal amplifying circuit (3), the positive input end of the other operational amplifier is connected with the positive output end PH + of the signal source, and the output end of the operational amplifier is divided by feedback resistors R4 and R5 and then input to the reverse input end of the operational amplifier.
4. A PH measuring sensor module according to claim 3, wherein: the resistor RP1 is an adjustable potentiometer; the resistor R2 is connected in parallel with a filter capacitor C1.
5. A PH measurement sensor module as claimed in claim 1, wherein: the power supply indicating circuit (4); the power supply indicating circuit (4) comprises a light emitting diode LED0, and a current limiting resistor R3 is connected in series with a light emitting diode LED 0.
6. A pH measuring sensor module according to claim 5, wherein: also comprises a temperature compensation circuit (5); the temperature compensation circuit (5) comprises a digital temperature sensor, a VDD pin of the digital temperature sensor is connected with a 5.0V power supply, an I/O pin outputs a temperature measurement signal, and a GND pin is grounded; the I/O pin is connected with a pull-up resistor R6.
7. A PH measurement sensor module as claimed in claim 1, wherein: also includes a BNC connector (6).
8. A pH measuring sensor module according to claim 6, wherein: the PH value measurement sensor module is provided with two grounds of GND1 and GND 2; the power supply indicating circuit (4), the temperature compensating circuit (5) and the 2.5V precise power supply circuit (1) are connected with GND1 in common, and the signal source voltage bias circuit (2) and the signal amplifying circuit (3) are connected with GND2 in common; GND1 and GND2 are connected by a zero resistance and a magnetic bead.
9. A pH measuring sensor module according to claim 6, wherein: the PH value measuring sensor module is provided with VCC, GND1, GND2, PH-OUT, 2.5V and T1 external interfaces.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023264924.2U CN213987227U (en) | 2020-12-30 | 2020-12-30 | PH value measurement sensor module |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023264924.2U CN213987227U (en) | 2020-12-30 | 2020-12-30 | PH value measurement sensor module |
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| Publication Number | Publication Date |
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| CN213987227U true CN213987227U (en) | 2021-08-17 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202023264924.2U Active CN213987227U (en) | 2020-12-30 | 2020-12-30 | PH value measurement sensor module |
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| CN (1) | CN213987227U (en) |
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