阅读说明：本技术 一种适应性强的ph控制仪 (PH controller with strong adaptability ) 是由 林善平 陈志扬 魏小东 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种适应性强的PH控制仪,包括PH采样电路、温度补偿采样电路、MCU控制单元和显示单元,PH采样电路、温度补偿采样电路和显示单元均分别与MCU控制单元信号连接,温度补偿采样电路包括电压转换器Q1、四路满摆幅运算放大器U4和若干电阻。本发明适应性强的PH控制仪,可兼容四种温度补偿信号的采集,允许不同温度下水溶液PH值测量时,四种温度补偿信号的切换接入,满足了各种工况下PH测量的温度补偿,其应用范围广,使用灵活。(The invention discloses a PH controller with strong adaptability, which comprises a PH sampling circuit, a temperature compensation sampling circuit, an MCU (microprogrammed control unit) and a display unit, wherein the PH sampling circuit, the temperature compensation sampling circuit and the display unit are respectively in signal connection with the MCU, and the temperature compensation sampling circuit comprises a voltage converter Q1, a four-way full-swing operational amplifier U4 and a plurality of resistors. The PH controller with strong adaptability can be compatible with the collection of four temperature compensation signals, allows the switching in of the four temperature compensation signals when the PH values of the aqueous solution are measured at different temperatures, meets the temperature compensation of PH measurement under various working conditions, and has wide application range and flexible use.)

1. The utility model provides a strong adaptability's PH controller, includes PH sampling circuit, temperature compensation sampling circuit, MCU the control unit and the display element, PH sampling circuit, temperature compensation sampling circuit and display element equally divide do not with MCU the control unit signal connection, its characterized in that: the temperature compensation sampling circuit comprises a voltage converter Q1, a four-way full-swing operational amplifier U4 and a plurality of resistors, wherein a power supply voltage is introduced into the input end of a voltage converter Q1, a resistor R5 is connected in series between the output end of the voltage converter Q1 and the non-inverting input end of a first-way operational amplifier U4-1 in a four-way full-swing operational amplifier U4, the inverting input end of the first-way operational amplifier U4-1 is grounded after being connected in series with a resistor R9, a resistor R3 is connected in series between the inverting input end and the output end of the first-way operational amplifier U4-1, a sampling resistor R10 is connected in series between the output end of the first-way operational amplifier U4-1 and the non-inverting input end of a second-way operational amplifier U4-2 in a four-way full-swing operational amplifier U4, a temperature compensation signal sensed by a temperature sensor is connected to the non-inverting input end of the second-way operational amplifier, a resistor R7 is connected between the output end of the second operational amplifier U4-2 and the equidirectional input end of the first operational amplifier U4-1 in series, a resistor R39 is connected between the equidirectional input end of the second operational amplifier U4-2 and the homophase input end of the third operational amplifier U4-3 in the four-way full-swing operational amplifier U4 in series, the inverting input end of the third operational amplifier U4-3 is grounded after being connected with a resistor R8 in series, a resistor R4 is connected between the inverting input end of the third operational amplifier U4-3 and the output end in series, the output end of the third operational amplifier U4-3 is used as the output end of the temperature compensation sampling circuit and is connected with the MCU control unit, the temperature compensation sampling circuit has four groups of resistance combinations which are in one-to-one correspondence and switchable with four temperature compensation signals NTC 7371, NTC10K, NTC PT100 and PT1000, and each group of resistance, The resistor R8 and the resistor R4 are formed by combining the three elements together; wherein the content of the first and second substances,

the PH sampling circuit is used for collecting a PH value signal of the aqueous solution sensed by the PH electrode in real time and transmitting the PH value signal to the MCU control unit;

the temperature compensation sampling circuit is used for accessing a temperature compensation signal sensed by the temperature sensor, converting the accessed temperature compensation signal into a voltage signal from a resistance signal, and outputting the temperature compensation signal converted into the voltage signal to the MCU control unit after being amplified by a three-way operational amplifier U4-3 in a four-way full swing operational amplifier U4;

the MCU control unit is used for receiving a PH value signal transmitted by the PH sampling circuit and a temperature compensation signal transmitted by the temperature compensation sampling circuit, and transmitting the detected PH value and the detected temperature compensation value to the display unit for displaying.

2. The adaptable PH controller of claim 1, wherein: the temperature compensation sampling circuit further comprises a TVS tube T1 and a capacitor C17, wherein the TVS tube T1 and the capacitor C17 are connected between the non-inverting input end of the second operational amplifier U4-2 and the ground in parallel.

3. The adaptable PH controller of claim 1, wherein: an RC filter circuit consisting of R6 and a capacitor C9 is connected between the output end of the third operational amplifier U4-3 and the MCU control unit.

4. The adaptable PH controller of claim 1, wherein: the PH sampling circuit comprises an LC filter circuit, an RC filter circuit, a front-stage operational amplifier circuit, a rear-stage operational amplifier circuit and an AD conversion circuit which are sequentially connected, and the AD conversion circuit is connected with the MCU control unit.

5. The adaptable PH controller of claim 1, wherein: the MCU control unit is connected with the communication circuit through a signal.

6. The adaptable PH controller of claim 1, wherein: the transmission output circuit is in signal connection with the MCU control unit.

7. The adaptable PH controller of claim 1, wherein: the device also comprises a DO output circuit, wherein the DO output circuit is in signal connection with the MCU control unit.

8. The adaptable PH controller of claim 1, wherein: the machine shell comprises a machine shell body, wherein tracks are horizontally arranged on two side walls of the machine shell body, the tracks comprise a latch track and a dovetail groove guide rail which are sequentially distributed from the back surface to the front surface of the machine shell body, the latch track is composed of a plurality of latch grooves which are distributed in parallel and vertically arranged along the tracks, the cross section of the dovetail groove guide rail is in a dovetail shape, a Y-shaped buckle is respectively arranged on the tracks on the two side surfaces of the machine shell body, the Y-shaped buckle comprises a horizontal root part and a fork corner part, a latch part and a dovetail slide block part are sequentially distributed on the horizontal root part along the horizontal direction, the latch part is composed of at least one latch tooth which is distributed in parallel and vertically arranged, the latch tooth is a triangular wave-shaped inclined tooth, the peak of the inclined tooth inclines towards the back surface of the machine shell body, the latch tooth of the latch part is embedded in the latch groove of the, the horizontal root is close to the one end extension of latch portion has for the dismantlement portion of casing body side perk, and fork bight is connected with the one end that horizontal root is close to forked tail slider portion, and the fork bight uses horizontal root to set up as symmetry center symmetry, and when the casing body passed the mounting hole on the switch board cabinet board and installed on the switch board body, the two free end angles in fork bight portion of Y type buckle touched with the cabinet board top of switch board.

9. The adaptable PH controller of claim 8, wherein: the track is close to the orbital one end of latch and is uncovered the setting.

10. The adaptable PH controller of claim 8, wherein: the fork corner is arc.

Technical Field

The invention relates to the technical field of instruments, in particular to a PH controller with strong adaptability.

Background

The PH controller is a high intelligent on-line continuous monitor, is mainly used for monitoring and controlling the PH value of water quality, and is widely applied to sewage treatment, environmental monitoring, food sanitation and household tap water detection. The PH value of water quality is closely related to the temperature of aqueous solution, and for accurately measuring the PH value of aqueous solution, the temperature of aqueous solution is usually compensated, and the temperature compensation of the PH controller at the present stage mainly has two modes, one mode is manual compensation by adopting software, namely, a fixed temperature value is manually set in the PH controller for compensation, and the other mode is real-time compensation by externally connecting a temperature sensor. Because the monitoring of PH is the continuous process, and this continuous process, the temperature of aqueous solution is real-time change usually, and through setting up the manual compensation of a fixed temperature value, because the temperature of aqueous solution can not accurately be responded to the fixed temperature value of its compensation, so, the accuracy of the PH value that manual compensation mode measured is lower than the mode of compensating in real time through temperature sensor, and temperature compensation more in the detection is the mode of adopting a temperature sensor to carry out real-time compensation.

During real-time compensation, because the working conditions of the aqueous solutions in different application occasions have larger temperature differences, the aqueous solutions in different temperature sections are subjected to more accurate temperature compensation, and temperature sensors with different measuring ranges and corresponding to the temperatures of the aqueous solutions are required to be adopted for temperature compensation. The PH controller temperature compensation signals mainly include four types, namely NTC1K, NTC10K, PT100 and PT1000, and the four types of temperature compensation signals have different temperature measuring ranges and precision levels. The traditional PH controller only has one type of temperature compensation signals, one type of PH controller can only be applied to the temperature compensation of aqueous solution within the range of the measuring range and with the accuracy grade suitable for the pH controller, and the application range is small. In order to improve the application capability of the pH controller, the pH controller with two temperature compensation signals is designed at the present stage so as to be compatible with the aqueous solutions under different working conditions, but the requirements of different users under different working conditions cannot be met in practice, so that the application range is limited, and the popularization difficulty is high.

Disclosure of Invention

The invention aims to provide a pH controller with strong adaptability.

The technical scheme for realizing the purpose of the invention is as follows: a PH controller with strong adaptability comprises a PH sampling circuit, a temperature compensation sampling circuit, an MCU control unit and a display unit, wherein the PH sampling circuit, the temperature compensation sampling circuit and the display unit are respectively in signal connection with the MCU control unit, the temperature compensation sampling circuit comprises a voltage converter Q1, a four-way full-swing operational amplifier U4 and a plurality of resistors, a power supply voltage is introduced into the input end of the voltage converter Q1, the output end of the voltage converter Q1 is connected with a resistor R5 in series between the non-inverting input ends of a first path operational amplifier U4-1 in the four-way full-swing operational amplifier U4, the inverting input end of the first path operational amplifier U4-1 is connected with a resistor R9 in series and then grounded, the inverting input end of the first path operational amplifier U4-1 is connected with a resistor R3 in series between the inverting input ends, the output end of the first path operational amplifier U4-1 is connected with a sampling resistor R10 in series between the non-inverting input ends of a second path operational amplifier, the non-inverting input end of the second operational amplifier U4-2 is connected with a temperature compensation signal sensed by a temperature sensor, the inverting input end and the output end of the second operational amplifier U4-2 are connected to form a voltage follower, a resistor R7 is connected in series between the output end of the second operational amplifier U4-2 and the non-inverting input end of the first operational amplifier U4-1, a resistor R39 is connected in series between the non-inverting input end of the second operational amplifier U4-2 and the non-inverting input end of a third operational amplifier U4-3 in the four full-swing operational amplifier U4, the inverting input end of the third operational amplifier U4-3 is grounded after being connected with the resistor R8 in series, a resistor R4 is connected in series between the inverting input end and the output end of the third operational amplifier U4-3, and the output end of the third operational amplifier U4-3 is used as the output end of the, The temperature compensation sampling circuit is connected with the MCU control unit, four groups of switchable resistor combinations with resistance values corresponding to four temperature compensation signals NTC1K, NTC10K, PT100 and PT1000 one by one are arranged in the temperature compensation sampling circuit, and each group of resistor combination is formed by combining three elements, namely a sampling resistor R10, a resistor R8 and a resistor R4; wherein the content of the first and second substances,

the PH sampling circuit is used for collecting a PH value signal of the aqueous solution sensed by the PH electrode in real time and transmitting the PH value signal to the MCU control unit;

the temperature compensation sampling circuit is used for accessing a temperature compensation signal sensed by the temperature sensor, converting the accessed temperature compensation signal into a voltage signal from a resistance signal, and outputting the temperature compensation signal converted into the voltage signal to the MCU control unit after being amplified by a three-way operational amplifier U4-3 in a four-way full swing operational amplifier U4;

the MCU control unit is used for receiving a PH value signal transmitted by the PH sampling circuit and a temperature compensation signal transmitted by the temperature compensation sampling circuit, and transmitting the detected PH value and the detected temperature compensation value to the display unit for displaying.

Furthermore, the temperature compensation sampling circuit further comprises a TVS tube T1 and a capacitor C17, wherein the TVS tube T1 and the capacitor C17 are connected in parallel between the non-inverting input terminal of the second operational amplifier U4-2 and the ground. When the temperature sensor is damaged or short-circuited, the sampling voltage amplified and output by the second path of operational amplifier U4-2 in the four-path full-swing operational amplifier U4 is directly loaded on the third path of operational amplifier U4-3 in the four-path full-swing operational amplifier U4, which may cause the voltage amplified and output by the third path of operational amplifier U4-3 to be too large, and burn out the MCU control unit behind the MCU. The TVS tube T1 and the capacitor C17 form a signal clamping circuit, the TVS tube T1 in the signal clamping circuit is in a parallel connection state with the input voltage of the temperature sensor, the overvoltage voltage and the overvoltage current can be transiently clamped, and the TVS tube T1 automatically restores to a high-resistance state after the input voltage of the temperature sensor restores to a normal state, namely, the signal clamping circuit can effectively prevent the temperature sensor from being damaged, so that the input resistance of the temperature sensor is short-circuited to cause overvoltage, and other circuits are damaged.

Further, an RC filter circuit consisting of R6 and a capacitor C9 is connected between the output end of the third operational amplifier U4-3 and the MCU control unit. Due to the arrangement of the RC filter circuit, interference signals can be effectively reduced, and temperature compensation signals collected and input to the MCU control unit are enabled to be purer.

Further, the PH sampling circuit comprises an LC filter circuit, an RC filter circuit, a front-stage operational amplifier circuit, a rear-stage operational amplifier circuit and an AD conversion circuit which are sequentially connected, and the AD conversion circuit is connected with the MCU control unit. LC filter circuit carries out high frequency filtering to PH acquisition signal, and RC filter circuit carries out low frequency filtering to PH acquisition signal, and preceding stage operational amplifier circuit and back stage operational amplifier circuit accomplish the collection and the enlargies of PH signal, and AD converting circuit converts the analog voltage signal who gathers into the digital signal that MCU controller can receive.

Further, the PH controller with strong adaptability further comprises a communication circuit, and the communication circuit is in signal connection with the MCU control unit. The communication circuit is used for connecting the PH controller with external equipment for communication, so that the external equipment can read the related parameters of the PH controller and the information such as real-time PH value, temperature compensation value, alarm state and the like through the communication circuit and the communication protocol content. The communication circuit is usually a 485 communication circuit, and includes 1 485 communication conversion chip NSi83085, three TVS protection tubes, and two current limiting resistors, wherein the TVS protection tubes are used for protecting pins of the 485 communication conversion chip NSi83085 from being broken down by external strong electric signals, and the two current limiting resistors are used for limiting the current of two terminals of A, B of the 485 communication output.

Furthermore, the PH controller with strong adaptability further comprises a transmitting output circuit, and the transmitting output circuit is in signal connection with the MCU control unit. The transmitting output circuit is used for receiving a PWM (pulse-width modulation) port duty ratio signal of the MCU control unit, converting a displayed PH value into a 4-20mA signal of an analog quantity, and transmitting and outputting the signal to other external equipment in real time to realize synchronous display.

Further, the PH controller with strong adaptability further comprises a DO output circuit, and the DO output circuit is in signal connection with the MCU control unit. The DO output circuit is used for receiving signals from the MCU control unit to complete the state switching control of the turning over of the relay switch state, whether the buzzer buzzes or not and the like so as to regulate and control the alarm equipment or other equipment.

Further, the PH controller with strong adaptability comprises a machine shell body, wherein tracks are horizontally arranged on two side walls of the machine shell body and comprise a latch track and a dovetail groove guide rail which are sequentially distributed from the back surface to the front surface of the machine shell body, the latch track is composed of a plurality of latch grooves which are distributed in parallel along the tracks and are vertically arranged, the cross section of the dovetail groove guide rail is in a dovetail shape, a Y-shaped buckle is respectively arranged on the tracks on the two side surfaces of the machine shell body and comprises a horizontal root part and a fork angle part, a latch part and a dovetail slide block part are sequentially distributed on the horizontal root part in the horizontal direction, the latch part is composed of at least one latch which is distributed in parallel and is vertically arranged, the latch is triangular wave-shaped helical teeth, the helical tooth wave crest of the latch part inclines towards the back surface of the machine shell body, and the dovetail slide block part is slidably arranged on the dovetail groove guide rail and is clamped, Agree with mutually with the dovetail guide rail, the horizontal root is close to the one end extension of latch portion has the dismantlement portion for casing body side perk, and fork bight is connected with the one end that horizontal root is close to forked tail slider portion, and the fork bight uses horizontal root to set up as symmetry center symmetry, and when the casing body passed the mounting hole on the switch board cabinet board and installs on the switch board body, two free end angles in fork bight of Y type buckle and the cabinet board top of switch board touched. The instrument enclosure installed in the Y-shaped buckle manner is simple in installation structure, and only the dovetail slide block part of the Y-shaped buckle is needed to be installed on the dovetail groove guide rail of the enclosure body track and pushed forward; the clamping tooth part and the dovetail sliding block part are horizontally distributed front and back instead of vertically distributed up and down, so that the clamping tooth part is slightly influenced by the limiting effect of the dovetail sliding block part, when the Y-shaped buckle is disassembled or backwards adjusted, the disassembling part is outwards buckled, the clamping tooth part can be more easily moved from the clamping tooth groove, and the operation is easier; moreover, the fork angle part of the Y-shaped buckle lying on the side has higher strength than that of the outward-opened inverted splayed structure.

Further, the track is close to the orbital one end of latch and is uncovered the setting. The horizontal root length of Y type buckle is longer, for installing forked tail slider portion on the dovetail guide rail, the track is close to orbital one end of latch and needs to have certain installation space, and when the track is close to the orbital one end of latch and uncovered setting, can make things convenient for the installation of Y type buckle, especially with forked tail slider portion installation on the dovetail guide rail.

Further, the fork corner is arc-shaped. Fork angle portion can be V-arrangement, also can be the arc, compares V-arrangement, and arc fork angle portion incurved, and when fork angle portion top touched the cabinet board of switch board, the resistance that fork angle portion can bear is intensity bigger promptly.

Furthermore, the machine shell body comprises a front frame, a middle frame and a rear frame, a display screen mounting opening is formed in the front face of the front frame, the front end of the middle frame is mounted with a front frame bolt, the bottom of the rear end of the middle frame is hinged with the bottom of the rear frame to form a flip structure, the upper portion of the rear end of the middle frame is mounted with a rear frame upper portion bolt, and a rail is arranged on the side face of the middle frame. The center forms flip structure with the back frame hinge joint, compares full bolt installation, and the dismouting is more swift.

Furthermore, the rear end of the middle frame is provided with an inwards concave clamping groove ring, the front end of the rear frame is provided with an outwards convex clamping tooth ring, and the clamping tooth ring is clamped in the clamping groove ring. The latch ring card of back frame is located the draw-in groove intra-annular of center, when playing the positioning action, because of the lock gap is little, has better water-proof effects.

The PH controller with strong adaptability of the invention adopts a four-way full-swing operational amplifier U4 to carry out operational amplification in a temperature compensation sampling circuit, because the full-swing operational amplifier can carry out full-swing operational amplification output, the output voltage can be infinitely close to the input voltage, the available voltage range during the operational amplification is large, the swing amplitude of the output signal is wide, and the allowable change range of the input resistance is large, thus, when the voltage signals converted by the temperature sensors are dynamically changed along with the change of the temperature of aqueous solution due to the difference of the resistance signal grades of the temperature sensors, the four-way full-swing operational amplifier U4 can fully utilize the whole dynamic voltage range and cooperate with the selection of a sampling resistor R10 for adjusting the size of the sampling voltage, a resistor R4 for adjusting the multiple of the output voltage amplification of the operational amplification and a resistor R8, the voltage signals converted by different temperature sensor signals can be operated and controlled within the voltage range which is externally allowed to be received by the MCU control unit, so that the compatibility of four temperature compensation signals required by PH measurement is realized, the acquisition of the temperature compensation signals required by most of aqueous solutions when the PH value is measured is met, the application range is wide, and the use is flexible.

Drawings

FIG. 1 is a circuit diagram of an adaptable pH control instrument according to the present invention;

FIG. 2 is a circuit diagram of a PH sampling circuit of the PH controller with high adaptability of the present invention;

FIG. 3 is a circuit diagram of a temperature compensated sampling circuit of the adaptable pH controller of the present invention;

FIG. 4 is an equivalent circuit diagram of FIG. 3;

FIG. 5 is a schematic perspective view of an adaptable pH control apparatus according to the present invention;

FIG. 6 is a schematic view of an assembly of the pH controller of the present invention with an enhanced adaptability from a first viewing angle;

FIG. 7 is a schematic view of an assembly of the pH controller of the present invention from a second perspective with enhanced adaptability;

FIG. 8 is a schematic view showing an assembly structure of a center frame and a Y-type buckle of the pH controller according to the present invention;

FIG. 9 is a schematic view of the left buckle of FIG. 6;

FIG. 10 is a schematic diagram of a control cabinet with an adaptable pH control according to the present invention.

Detailed Description

The following detailed description of the preferred embodiments of the pH control apparatus according to the present invention will be made with reference to the accompanying drawings:

as shown in fig. 1, the PH controller with high adaptability comprises a PH sampling circuit 100, a temperature compensation sampling circuit 200, an MCU control unit 300 and a display unit 400, wherein the PH sampling circuit 100, the temperature compensation sampling circuit 200 and the display unit 400 are respectively in signal connection with the MCU control unit 300. As shown in fig. 3 and 4, the temperature compensation sampling circuit 200 includes a voltage converter Q1, a four-way full-swing operational amplifier U4, and a plurality of resistors, wherein a supply voltage is applied to an input terminal of the voltage converter Q1, a resistor R5 is connected in series between an output terminal of the voltage converter Q1 and a non-inverting input terminal of a first operational amplifier U4-1 in the four-way full-swing operational amplifier U4, an inverting input terminal of the first operational amplifier U4-1 is connected in series with the resistor R9 and then grounded, a resistor R3 is connected in series between an inverting input terminal and an output terminal of a first operational amplifier U4-1, a sampling resistor R10 is connected in series between an output terminal of the first operational amplifier U4-1 and a non-inverting input terminal of a second operational amplifier U4-2 in the four-way full-swing operational amplifier U4, a non-inverting input terminal of the second operational amplifier U4-2, the inverting input end and the output end of a second operational amplifier U4-2 are connected to form a voltage follower, a resistor R7 is connected in series between the output end of the second operational amplifier U4-2 and the inverting input end of a first operational amplifier U4-1, the inverting input end of the second operational amplifier U4-2 and the non-inverting input end of a third operational amplifier U4-3 in a four-way full swing operational amplifier U4 are connected in series with a resistor R39, the inverting input end of the third operational amplifier U4-3 is connected in series with a resistor R8 and then grounded, a resistor R4 is connected in series between the inverting input end and the output end of the third operational amplifier U4-3, the output end of the third operational amplifier U4-3 is used as the output end of the temperature compensation sampling circuit 200 and is connected with the MCU control unit 300, the temperature compensation sampling circuit 200 has four sets of resistors corresponding to and switchable with the four temperature compensation signals NTC1K, NTC10K, PT100 and PT1000 one by one, each group of resistor combination is formed by combining three elements of a sampling resistor R10, a resistor R8 and a resistor R4; wherein the content of the first and second substances,

the PH sampling circuit 100 is used for collecting a PH value signal of the aqueous solution sensed by the PH electrode in real time and transmitting the PH value signal to the MCU control unit 300;

the temperature compensation sampling circuit 200 is configured to access a temperature compensation signal (i.e., a temperature sensor signal) sensed by the temperature sensor 1000, convert the accessed temperature compensation signal into a voltage signal from a resistance signal, amplify the temperature compensation signal converted into the voltage signal by a three-way operational amplifier U4-3 of a four-way full swing operational amplifier U4, and output the amplified temperature compensation signal to the MCU control unit 300;

the MCU control unit 300 is configured to receive the PH signal from the PH sampling circuit 100 and the temperature compensation signal from the temperature compensation sampling circuit 200, and send the detected PH and temperature compensation values to the display unit 400 for display.

In the PH controller with high adaptability of the present invention, the PH sampling circuit 100 is configured to collect a PH signal of an aqueous solution sensed by the PH electrode in real time, and transmit the PH signal to the MCU control unit 300. In the present invention, as shown in fig. 2, the PH sampling circuit 100 generally includes an LC filter circuit 1001, an RC filter circuit 1002, a pre-stage operational amplifier circuit 1003, a post-stage operational amplifier circuit 1004, and an AD conversion circuit 1005, which are connected in sequence, and the AD conversion circuit 1005 is connected to the MCU control unit 300. The LC filter circuit 1001 performs high-frequency filtering on the PH acquisition signal, the RC filter circuit 1002 performs low-frequency filtering on the PH acquisition signal, the front-stage operational amplifier circuit 1003 and the rear-stage operational amplifier circuit 1004 complete acquisition and amplification of the PH signal, and the AD conversion circuit 1005 converts the acquired analog voltage signal into a digital signal which can be received by the MCU controller.

In the PH controller with high adaptability of the present invention, in the temperature compensation sampling circuit 200, the power supply voltage is converted into the sampling voltage meeting the requirements after passing through the voltage converter Q1, for example, the power supply voltage is 3.3V in this embodiment, the sampling voltage is 1.5V after passing through the voltage converter Q1, and the voltage converter Q1 makes the circuit voltage meet the requirements of the back-end circuit, and the damage of the components in the back-end circuit is not caused; a first path of operational amplifier U4-1, a resistor R5, a resistor R9 and a resistor R3 in the four-path full-swing operational amplifier U4 form an in-phase proportional operational amplifier circuit, and a sampling voltage is amplified to about 3.6V by the proportional operational amplifier circuit and is loaded to a sampling resistor R10; a follower formed by the second path of operational amplifier U4-2 forms negative feedback, so that the sampling voltage output after being amplified by the first path of operational amplifier U4-1 is more stable; the sampling voltage of 3.6V is amplified by an in-phase proportional operational amplifying circuit consisting of a first operational amplifier U4-1, the voltage is regulated by a sampling resistor R10, the size of the sampling voltage finally supplied to the temperature sensor 1000 meets the sampling requirement of the temperature sensor signal, and meanwhile, the temperature sensor signal is converted into a voltage signal from the resistance signal under the comparative partial pressure of the resistance signals of the sampling resistor R10 and the temperature sensor 1000; the third operational amplifier U4-3 and the resistor R39, the resistor R4 and the resistor R8 in the four-way full-swing operational amplifier U4 also form an in-phase proportional operational amplifier circuit, and the temperature sensor signal is amplified by the in-phase proportional operational amplifier circuit formed by the third operational amplifier U4-3 and is controlled within the voltage range allowed to be received by the MCU control unit 300, and then is sent to the MCU control unit 300 to finish the acquisition of the temperature compensation signal.

The four-way full-swing operational amplifier U4 of the PH controller with strong adaptability of the invention has the full-swing characteristic, can realize the composite rail-to-rail operational amplifier control, compared with the common operational amplifier, the four-way full-swing operational amplifier U4 can lead the input voltage and the output voltage to be infinitely close to the power supply voltage, allows the resistance signal induced by the temperature sensor 1000 to be changed in a larger range, and can be compatible with the collection of the existing four temperature sensor signals (NTC 1K, NTC10K, PT100 and PT 1000).

In the PH controller with high adaptability of the present invention, the temperature compensation sampling circuit 200 uses three operational amplifiers, so the adopted full swing operational amplifier is at least four full swing operational amplifiers U4. Four operational amplifiers are integrated in the four-way full-swing operational amplifier U4, wherein three operational amplifiers are used, and one operational amplifier is not used. In the invention, the four-way full-swing operational amplifier U4 may generally adopt an SGM8424 chip, a MAX4487 chip, a MAX4094 chip, a LMX324 chip, and the like.

In the PH controller with strong adaptability, in the temperature compensation sampling circuit 200, the sampling resistor R10 is used for regulating the voltage of a sample, and the voltage regulation result is required to meet the sampling requirement of a temperature sensor signal; the resistor R4 and the resistor R8 determine the amplification factor of the temperature sensor signal in the in-phase proportional operational amplifier circuit formed by the third operational amplifier U4-3, and require amplification, and the upper limit value of the amplified temperature sensor signal is controlled within the voltage range allowed to be received by the MCU control unit 300. However, of the four temperature sensor signals (NTC 1K, NTC10K, PT100 and PT 1000), the resistance values of PT100 and PT1000 at the same temperature are different by 10 times, for example, at 0 degree, PT100 is 100K Ω, and PT1000 at the same temperature is 1000K Ω, and NTC1K and NTC10K are similar, and these four signals are collected in the same sampling voltage and op-amp circuit, and not only the sampling voltage is regulated by sampling resistor R10, but also in a rail-to-rail integrated op-amp with full swing, the op-amp ratio is regulated by switching resistor R4 and resistor R8, so that the temperature sensor signal finally input to MCU control unit 300 can be collected. That is to say, even when the full swing integrated transport is put down, the values of the sampling resistor R10, the resistor R4 and the resistor R8 are also closely related to the signal acquisition of the temperature sensor, and are required to be adapted to the signals of the temperature sensors, and only when the values of the sampling resistor R10, the resistor R4 and the resistor R8 are adapted, the signal acquisition of the temperature sensor can be successful. Therefore, in order to realize the collection of the existing conventional four temperature sensor signals (NTC 1K, NTC10K, PT100 and PT 1000), four groups of resistor combinations composed of three elements of the sampling resistor R10, the resistor R4 and the resistor R8 are provided, the resistances of the sampling resistor R10, the resistor R4 and the resistor R8 in the four groups of resistor combinations correspond to the four temperature sensor signals (NTC 1K, NTC10K, PT100 and PT 1000) one by one, in this embodiment, in the four groups of resistor combinations corresponding to the four temperature sensor signals (NTC 1K, NTC10K, PT100 and PT 1000), the values of the sampling resistor R10, the resistor R4 and the resistor R8 of each element are as shown in the following table.

Temperature sensor signal	Sampling resistance R10 (K omega)	Resistance R4 (K omega)	Resistance R8 (K omega)
				NTC1K	10	12.4	1.5
NTC10K	13	2	110
				PT100	0.51	10	1.2
PT1000	1.2	15	12

The PH controller with strong adaptability of the present invention includes the values of the sampling resistor R10, the resistor R4 and the resistor R8 in the four groups of resistor combinations shown in the above table, but not limited to the above table.

When a user accesses different temperature sensors 1000 from the outside, the PH controller with strong adaptability of the present invention needs to set temperature compensation types correspondingly in the parameters of the present invention, switch the input signal types of the temperature sensors, and then access the temperature sensor signals to the temperature compensation sampling circuit 200. According to the invention, aiming at the acquisition of different temperature sensor signals, when four groups of resistor combinations formed by taking a sampling resistor R10, a resistor R4 and a resistor R8 as elements are switched, the switching can be realized by a jumper, a dial or an electronic switch, and specifically, manual welding replacement or code switch switching can be adopted, or the electronic switch is used, and an MCU controller sends a switching signal to the electronic switch for switching.

In the PH controller with high adaptability of the present invention, preferably, the temperature compensation sampling circuit 200 further includes a TVS transistor T1 and a capacitor C17, and the TVS transistor T1 and the capacitor C17 are connected in parallel between the non-inverting input terminal of the second path of operational amplifier U4-2 and ground. When the temperature sensor 10 is damaged or short-circuited, the sampling voltage amplified and output by the second operational amplifier U4-2 in the four-way full-swing operational amplifier U4 is directly loaded on the third operational amplifier U4-3 in the four-way full-swing operational amplifier U4, which may cause the voltage amplified and output by the third operational amplifier U4-3 to be too large, and burn out the MCU control unit 300 behind. The TVS tube T1 and the capacitor C17 form a signal clamp circuit, the TVS tube T1 in the signal clamp circuit is in parallel with the input voltage of the temperature sensor 1000, and can transiently clamp the overvoltage voltage and current, and the input voltage of the temperature sensor 1000 returns to a high-resistance state after returning to normal, that is, the signal clamp circuit can effectively prevent the temperature sensor 1000 from being damaged, which causes the short circuit of the input resistor of the temperature sensor 1000, resulting in overvoltage and other circuit damage.

In the PH controller with strong adaptability, an RC filter circuit consisting of R6 and a capacitor C9 is usually connected between the output end of the third operational amplifier U4-3 and the MCU control unit 300. Due to the arrangement of the RC filter circuit, interference signals can be effectively reduced, and temperature compensation signals collected and input to the MCU control unit 300 are enabled to be purer.

In the PH controller with high adaptability, the temperature compensation sampling circuit 200 amplifies a temperature compensation signal (i.e., a temperature sensor signal) sensed by the temperature sensor 1000 and sends the amplified temperature compensation signal to the MCU control unit 300; the MCU control unit 300 receives the PH signal from the PH sampling circuit 100 and the temperature compensation signal from the temperature compensation sampling circuit 200, and sends the detected PH and temperature compensation values to the display unit 400 for display.

In the PH controller with high adaptability of the present invention, the MCU control unit 300 may generally adopt 32-bit processors such as nuc029, stm32, etc.

The invention relates to a PH controller with strong adaptability, and a display unit 400 is an LCD display unit. The display unit 400 is used for receiving a control signal sent by the MCU control unit 300 and displaying information such as PH value, temperature compensation value, alarm state, etc. for human-computer interaction, and the display unit 400 is connected to the MCU controller via a flat cable. The display unit 400 may be an LED display unit or an LCD display unit, and preferably the display unit 400 is an LCD display unit because of the lower display requirements and the lower cost of the LCD display unit compared to the former.

The PH controller with high adaptability of the present invention generally further comprises a communication circuit 500, wherein the communication circuit 500 is in signal connection with the MCU control unit 300. The communication circuit 500 is used for connecting the PH controller with an external device for communication, so that the external device reads information such as PH controller related parameters, real-time PH value, temperature compensation value and alarm state through the communication circuit 500 and communication protocol content. The communication circuit 500 is generally a 485 communication circuit, and includes 1 485 communication conversion chip NSi83085, three TVS protection tubes, and two current limiting resistors, wherein the TVS protection tubes are used for protecting pins of the 485 communication conversion chip NSi83085 from being broken down by external strong electric signals, and the two current limiting resistors are used for limiting the current of two terminals of A, B of the 485 communication output.

The PH controller with high adaptability of the present invention generally further comprises a transmitting output circuit 600, wherein the transmitting output circuit 600 is in signal connection with the MCU control unit 300. The transmitting output circuit 600 is used for receiving the PWM port duty ratio signal of the MCU control unit 300, converting the displayed PH value into an analog 4-20mA signal, and transmitting and outputting the signal to other external devices in real time to realize synchronous display.

The PH controller with high adaptability of the present invention generally further comprises a DO output circuit 700, wherein the DO output circuit 700 is in signal connection with the MCU control unit 300. The DO output circuit 700 is used to receive a signal from the MCU control unit 300 to complete the state switching control of the inversion of the relay switch state and whether the buzzer is buzzing, etc., for the adjustment control of the alarm device or other devices.

The PH controller with strong adaptability of the invention is generally provided with a power circuit 800 for providing power for the PH controller, and the power circuit 800 generally comprises an EMC safety circuit, a rectifier bridge circuit, a switching power supply chip, a high-frequency transformer and a rectifying, voltage-stabilizing and filtering output circuit. The EMC safety circuit is used for protection and anti-interference design and comprises a thermal pressure sensitive tube, a safety capacitor, an inductor and the like; the rectifier bridge circuit consists of four rectifier diodes and is used for rectifying input alternating-current voltage into direct-current voltage; the switching power supply chip is used as a control chip to continuously adjust the output power of the power supply, so that the power supply circuit works in a stable state; the high-frequency transformer is responsible for converting voltage; and the rectification voltage-stabilizing filtering output circuit is used for carrying out rectification voltage-stabilizing output on each group of voltage of the secondary coil of the high-frequency transformer and is connected with the filtering capacitor in parallel at the output end.

The PH controller with strong adaptability of the invention adopts four paths of full-swing operational amplifiers U4 to carry out operational amplification in a temperature compensation sampling circuit 200, because the full-swing operational amplifiers can carry out full-swing operational amplification output, the output voltage can be infinitely close to the input voltage, the available voltage range during the operational amplification is large, the swing amplitude of the output signal is wide, and the allowable change range of the input resistance is large, thus, when the voltage signals converted by the temperature sensors are dynamically changed along with the change of the temperature of aqueous solution due to the difference of the resistance signal grades of the temperature sensors, the four paths of full-swing operational amplifiers U4 can fully utilize the whole dynamic voltage range and cooperate with the selection of a sampling resistor R10 for adjusting the size of the sampling voltage, a resistor R4 for adjusting the amplification factor of the output voltage of the operational amplification and a resistor R8, the voltage signals converted by different temperature sensor signals can be amplified and controlled within the voltage range which is externally allowed to be received by the MCU control unit 300, so that the compatibility of four temperature compensation signals required by PH measurement is realized, and the acquisition of the temperature compensation signals required by most of aqueous solutions in PH value measurement is met.

The PH controller with strong adaptability can be compatible with the collection of four temperature compensation signals, and allows the switching access of the four temperature compensation signals when the PH values of aqueous solutions at different temperatures are measured, so that the temperature compensation of PH measurement under various working conditions is met, and the PH controller has wide application range and flexible use; in the temperature compensation sampling circuit 200, after the four-way full-swing operational amplifier U4 is compatible with the operational amplifier of four temperature compensation signals, the number of peripheral circuits required by the operational amplifier is small, and the output signal input to the MCU control unit 300 only occupies one interface, so that compared with the case that four operational amplifier circuits are used to perform the operational amplifier on four temperature compensation signals, the latter circuit not only has more peripheral circuits, but also occupies four interfaces of the MCU control unit 300, and the operational amplifier circuit formed by the four-way full-swing operational amplifier U4 of the present invention has the advantages of simpler design, lower cost and higher precision.

The PH controller with strong adaptability can automatically compensate the temperature through four temperature sensors when measuring the PH value, and can also adopt manual compensation without connecting the temperature sensors. When the PH value is measured to compensate for the temperature, the PH value at the current temperature is usually converted to a PH value at 25 ℃ under the condition that other conditions are not changed, and the conversion process is completed by the MCU control unit 300, specifically, the MCU control unit 300 substitutes the detected temperature value into the fixed equation PH_t= PH₂₅(t +273.15)/(25+273.15), pH in fixed equation_tpH at t.degree.C, pH₂₅At 25 ℃ and t is the compensated temperature.

The PH controller with high adaptability of the invention comprises a PH sampling circuit 100, a temperature compensation sampling circuit 200, an MCU control unit 300, a display unit 400, a communication circuit 500, a transmission output circuit 600, a DO output circuit 700, a power supply circuit 800 and other circuits which are arranged on a circuit board 20, and the number of the circuit board 20 is not limited.

The PH controller with strong adaptability of the present invention, as shown in fig. 5 to 10, comprises a casing body 10, two side walls of the casing body 10 are horizontally provided with rails 1, the rails 1 comprise a latch rail 11 and a dovetail groove rail 12 which are sequentially distributed along the direction from the back to the front of the casing body 10, the latch rail 11 is composed of a plurality of vertically arranged latch grooves 111 which are distributed along the rails 1 in parallel, the cross section of the dovetail groove rail 12 is dovetail-shaped, a Y-shaped buckle 2 is respectively installed on the rails 1 on the two side surfaces of the casing body 10, the Y-shaped buckle 2 comprises a horizontal root part 21 and a fork angle part 22, the horizontal root part 21 is sequentially distributed with a latch part 211 and a dovetail slide block part 212 along the horizontal direction, the latch part 211 is composed of at least one vertically arranged latch 2111 which is distributed along the parallel, the latch part 2111 is a triangular waveform oblique tooth and the peak of the oblique tooth is inclined towards the back, the latch 2111 of the latch portion 211 is engaged with the latch groove 111 of the latch rail 11, the dovetail slider portion 212 is slidably mounted on the dovetail groove guide rail 12 and engaged with the dovetail groove guide rail 12, a detaching portion 23 tilted relative to the side surface of the enclosure body 10 extends from one end of the horizontal root portion 21 close to the latch portion 211, the fork corner portion 22 is connected with one end of the horizontal root portion 21 close to the dovetail slider portion 212, the fork corner portion 22 is symmetrically arranged by taking the horizontal root portion 21 as a symmetry center, when the enclosure body 10 passes through a mounting hole on a cabinet board of a control cabinet and is mounted on the control cabinet body, two free end angles 221 of the fork corner portion 22 of the Y-shaped buckle 2 are in top contact with the cabinet board 50 of the control cabinet.

According to the PH controller with strong adaptability, the latch 2111 is triangular wave-shaped inclined tooth, the wave crest of the inclined tooth inclines towards the back of the machine shell body 10, the latch 2111 of the latch part 211 is guaranteed to be clamped and embedded in the latch groove 111 of the latch rail 11, and when the Y-shaped buckle 2 is limited, the Y-shaped buckle 2 can be pushed towards the front of the machine shell body 10 but cannot be pushed towards the back of the machine shell body 10; the dovetail slide block part 212 is slidably mounted on the dovetail groove guide rail 12, and has the function of enabling the Y-shaped buckle 2 to slide along the track 1 while realizing the mounting of the Y-shaped buckle 2; the detaching part 23 is used for conveniently detaching or backwards adjusting the Y-shaped buckle 2, the detaching part 23 can be used for outwards buckling to enable the latch 2111 of the latch part 211 to be separated from the latch groove 111 of the latch rail 11, and then the Y-shaped buckle 2 is moved along the rail 1 or the Y-shaped buckle 2 is moved out of the rail 1; the fork corner 22 is used for fixing the housing after being mounted on the control cabinet by mounting stress.

When the PH controller with strong adaptability is arranged on a control cabinet, the dovetail slide block part 212 of the Y-shaped buckle 2 is slidably arranged on the dovetail groove guide rail 12 of the machine shell body track 1 and is pushed forwards, so that two free end angles 221 of the fork angle part 22 of the Y-shaped buckle 2 are in contact with the cabinet plate 50 of the control cabinet and generate deformation, and the latch 2111 of the latch part 211 of the Y-shaped buckle is clamped and embedded in the latch groove 111 of the latch track 11 to realize fixation while certain acting force is generated between the fork angle part 22 and the cabinet plate 50 due to the resistance to the deformation. When the Y-clip 2 is detached or adjusted backward, the detaching portion 23 is buckled outward, so that the latch 2111 of the latch portion 211 is separated from the latch groove 111 of the latch rail 11, and then the Y-clip 2 is moved along the rail 1 or the Y-clip 2 is moved out from the rail 1.

The PH controller with strong adaptability has a simple installation structure, and only the dovetail slide block part 212 of the Y-shaped buckle 2 is required to be installed on the dovetail groove guide rail 12 of the machine shell body track 1 and pushed forward; moreover, because the latch part 211 and the dovetail slider part 212 are horizontally distributed front and back instead of vertically distributed up and down, the latch part 211 is less influenced by the limit action of the dovetail slider part 212, when the Y-shaped buckle 2 is disassembled or adjusted backwards, the disassembly part 23 is buckled outwards, so that the latch part 211 can be more easily moved from the latch groove 111, and the operation is easier; the fork corner 22 of the Y-clip 2 has a stronger strength than the outwardly-extended inverted "v" shaped structure.

The PH controller with strong adaptability of the invention, the arrangement of the latch track 11, enables the mounting position of the Y-shaped buckle 2 to be adjusted back and forth, so as to adapt to the mounting on control cabinets with different thicknesses of the cabinet plate 50, or realize different mounting tightness, and enable the mounting to be more flexible.

The invention discloses a PH controller with strong adaptability, and preferably, one end of the rail 1, which is close to the latch rail 11, is open. The horizontal root 21 length of Y type buckle 2 is longer, and for installing dovetail slider portion 212 on dovetail guide rail 12, track 1 is close to the one end of latch track 11 and needs certain installation space, and when track 1 was close to the uncovered setting of one end of latch track 11, can make things convenient for the installation of Y type buckle 2, especially installs dovetail slider portion 212 on dovetail guide rail 12.

The present invention is a PH control instrument with enhanced adaptability, preferably with the fork corners 22 being curved. The fork corner 22 may be V-shaped or arc-shaped, and compared with the V-shape, the arc-shaped fork corner 22 is bent inward, and when the fork corner 22 touches the cabinet plate 50 of the control cabinet, the resistance, i.e., the strength, which the fork corner 22 can bear is larger.

The PH controller with strong adaptability of the invention, the casing body 10 usually includes a front frame 101, a middle frame 102 and a rear frame 103, the front of the front frame 101 has a display screen mounting port 1011, the front end of the middle frame 102 is mounted with the front frame 101 by bolts, the bottom of the rear end of the middle frame 102 is hinged with the bottom of the rear frame 103 to form a flip structure, the upper part of the rear end of the middle frame 102 is mounted with the upper part of the rear frame 103 by bolts, and the track 1 is arranged on the side surface of the middle frame 102. The front frame 101 is used for mounting a display screen or keys, the middle frame 102 is commonly used for mounting the circuit board 20, and the rear frame 103 is used for packaging and also has a plurality of wiring ports. The PH controller with strong adaptability of the invention has the advantages that the middle frame 102 and the rear frame 103 are hinged to form a flip structure, and compared with the full-bolt installation, the dismounting is quicker.

The PH controller with high adaptability of the present invention preferably has an open front end and a closed rear end of the middle frame 102, and the rear end of the middle frame 102 is provided with a wiring opening 1021. The wiring opening 1021 is used for the passage of circuit wiring. According to the invention, the rear end of the middle frame 102 is closed, the inner blocks of the middle frame 102 and the rear frame 103 are divided more obviously, and the whole structure strength is better under the condition that the rear end of the middle frame 102 is closed.

In the PH controller with high adaptability of the present invention, preferably, the inner wall of the middle frame 102 is provided with a guide plate groove 1022. The guide plate slots 1022 are provided to facilitate the mounting and fixing of the circuit board 20 in the middle frame 102.

In the PH controller with high adaptability of the present invention, preferably, the rear end of the middle frame 102 is provided with a concave snap ring 1023, the front end of the rear frame 103 is provided with a convex snap ring 1031, and the snap ring 1031 is snapped in the snap ring 1023. The latch ring 1031 card of the rear frame 103 is positioned in the slot ring 1023 of the middle frame 102, and has a positioning effect and a better waterproof effect because the buckling gap is small.

For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all should be considered as belonging to the protection scope of the invention.