External sensor intelligent identification receiving circuit for air conditioner refrigerating unit

Abstract

An external sensor intelligent identification receiving circuit for an air-conditioning refrigerating unit belongs to the technical field of signal receiving circuits, is connected between an external sensor and an MCU of an air-conditioning refrigerating unit controller, and comprises input ends AI + and AI-and an output end ADI, and a signal judgment circuit module is arranged between the input ends AI + and AI-and the output end ADI. An auxiliary circuit module matched with the signal judgment circuit by virtue of a channel analog switch U2 and a channel analog switch U3 is also arranged in the intelligent identification receiving circuit; and the signal judgment circuit module and the auxiliary circuit module form a voltage type receiving circuit, a current type receiving circuit or a resistance type receiving circuit by means of on-off of the channel analog switch U2 and the channel analog switch U3. By improving the circuit structure, voltage, current and resistance analog quantity signals can be intelligently adapted, the signal collecting and receiving functions are completed, and an air conditioning unit is easy to maintain.

Description

Technical Field

[0001] The invention belongs to the technical field of signal receiving circuits, and in particular relates to an external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit. Background Art

[0002] The current controllers of air-conditioning and refrigeration units need to be customized and developed according to the usage scenarios, which generally involve the AD acquisition function of external sensors. The signals of external sensors are generally of three types: voltage (1-5V), current (4-20mA), and resistance (10K-NTC). Usually, due to the different types and quantities of external sensors for different application models, the AD sampling function and configuration of the air-conditioning controller need to be customized according to the application situation. Different external sensor configurations have led to a variety of air-conditioning and refrigeration unit controller models, which are not convenient for maintenance and management, increase after-sales costs, and cannot guarantee the reliability and stability of new products.

[0003] Therefore, it is necessary to provide a circuit that can intelligently adapt to analog signal input of voltage, current, and resistance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an external sensor intelligent identification and receiving circuit for an air-conditioning refrigeration unit. By improving the circuit structure, it can intelligently adapt voltage, current, and resistance analog signals to complete the signal acquisition and receiving function, making the air-conditioning unit easier to maintain.

[0005] The technical solution adopted by the present invention is: an external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit, connected between the external sensor and the MCU of the air-conditioning refrigeration unit controller, the intelligent identification receiving circuit includes input terminals AI+, AI- and output terminals ADI, a signal judgment circuit module is arranged between the input terminals AI+, AI- and output terminals ADI, and an auxiliary circuit module is also arranged in the intelligent identification receiving circuit, which cooperates with the signal judgment circuit with the help of channel analog switches U2 and U3. The signal judgment circuit module and the auxiliary circuit module are connected and disconnected with the help of channel analog switches U2 and U3 to form a voltage-type receiving circuit, a current-type receiving circuit or a resistance-type receiving circuit.

[0006] Furthermore, the signal judgment circuit module includes a relay Repay and a resistor R12 connected in parallel and in series between the input terminals AI+ and AI-, a voltage-stabilizing diode D1 and a capacitor C1 connected in parallel with the relay Repay and the resistor R12, an inductor L1 and an inductor L2 respectively connected at both ends of the capacitor C1, a capacitor C2 whose two ends are respectively connected to the inductor L1 and the inductor L2, a capacitor C3 and a resistor R6 connected in parallel and in series with the capacitor C2, and on-off connection points R1+ and R1- arranged between the inductor L1 and the capacitor C2, the output terminal ADI is connected between the capacitor C3 and the resistor R6, one end of the capacitor C2 is connected to GND, the control end of the relay Repay is connected to the MCU, and the on-off connection points R1+ and R1- are connected to the channel analog switch U3.

[0007] Furthermore, the auxiliary circuit module includes a first auxiliary module connected to one end of the inductor L1 and the inductor L2 respectively, a second auxiliary module arranged in parallel with the on-off connection points R1+ and R1-, a third auxiliary module arranged between the second auxiliary module and the capacitor C2, and a fourth auxiliary module arranged in parallel with the capacitor C2; the first auxiliary module is a resistor R1, a resistor R2, a resistor R3 and a resistor R4 arranged in parallel, which are connected to the channel analog switch U2 via the on-off connection points I1+ and I1-; the second auxiliary module is a resistor R10 and a resistor R11 arranged in parallel, the on-off connection points V1+ and V1- of the resistor R10 are connected to the channel analog switch U2, and the on-off connection points I2+ and I1- of the resistor R11 are connected to the channel analog switch U2. I2- is connected to the channel analog switch U2; the third auxiliary module is a power supply REF3_3, a diode D2 and a resistor R5 arranged in series, and the on-off connection points R2+ and R2- between the power supply REF3_3 and the diode D2 are connected to the channel analog switch U3; the fourth auxiliary module is a resistor R7, a resistor R8 and a resistor R9 arranged in parallel, the on-off connection points V2+ and V2- of the resistor R7 are connected to the channel analog switch U2, the on-off connection points I3+ and I3- of the resistor R8 are connected to the channel analog switch U3, and the on-off connection points R3+ and R3- of the resistor R9 are connected to the channel analog switch U3.

[0008] Furthermore, the relay Repay model is APAN3105.

[0009] Furthermore, the model of the channel analog switch U2 and the channel analog switch U3 is SN74HC4066.

[0010] Furthermore, the identification and receiving method of the external sensor intelligent identification and receiving circuit includes: Step A. After the controller is powered on, the MCU controls the relay Repay to turn on, and at the same time controls the channel analog switch U3 to turn on and off the connection points R1+ and R1-; Step B. The input terminals AI+ and AI- receive external signals, and the output terminal ADI collects external analog signals converted by the signal judgment circuit module; If the voltage value of the external analog signal is not less than the threshold value M, the external signal is determined to be a voltage type signal; If the voltage value of the external analog signal is greater than 0 and less than the threshold M, the external signal is determined to be a current type signal; If the voltage value of the external analog signal is 0, the external signal is determined to be a resistance signal; Step C. After the external signal type is identified, the MCU controls the relay Repay to disconnect, and at the same time controls the channel analog switch U3 to disconnect the on-off connection points R1+ and R1-; C1. If the external signal is a voltage type signal, the MCU controls the channel analog switch U2 to conduct the on-off connection points V1+, V1- and the on-off connection points V2+, V2-; C2. If the external signal is a current type signal, the MCU controls the channel analog switch U2 and the channel analog switch U3 to respectively turn on and off the connection points I1+, I1-, the connection points I2+, I2-, and the connection points I3+, I3-; C3. If the external signal is a resistor type signal, the MCU controls the channel analog switch U3 to turn on and off the connection points R1+, R1-, the connection points R2+, R2-, and the connection points R3+, R3-.

[0011] The beneficial effects produced by adopting the present invention are as follows: the present invention has strong compatibility, applicability, reliability and stability for external signals, can intelligently adapt voltage, current and resistance analog signals, complete the signal acquisition and receiving function, and simplify the maintenance of the air-conditioning unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the circuit structure of the present invention. DETAILED DESCRIPTION

[0013] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0014] See attached Figure 1, an external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit is connected between the external sensor and the MCU of the air-conditioning refrigeration unit controller, the intelligent identification receiving circuit includes input terminals AI+, AI- and output terminals ADI, a signal judgment circuit module is arranged between the input terminals AI+, AI- and output terminals ADI, and an auxiliary circuit module is also arranged in the intelligent identification receiving circuit, which cooperates with the signal judgment circuit with the help of a channel analog switch U2 and a channel analog switch U3. The signal judgment circuit module and the auxiliary circuit module are connected and disconnected with the help of the channel analog switch U2 and the channel analog switch U3 to form a voltage type receiving circuit, a current type receiving circuit or a resistance type receiving circuit.

[0015] The signal judgment circuit module includes a relay Repay and a resistor R12 connected in parallel and in series between the input terminals AI+ and AI-, a voltage stabilizing diode D1 and a capacitor C1 connected in parallel with the relay Repay and the resistor R12, an inductor L1 and an inductor L2 connected at both ends of the capacitor C1 respectively, a capacitor C2 whose two ends are connected to the inductor L1 and the inductor L2 respectively, a capacitor C3 and a resistor R6 connected in parallel and in series with the capacitor C2, and on-off connection points R1+ and R1- arranged between the inductor L1 and the capacitor C2, the output terminal ADI is connected between the capacitor C3 and the resistor R6, one end of the capacitor C2 is connected to GND, the control end of the relay Repay is connected to the MCU, and the on-off connection points R1+ and R1- are connected to the channel analog switch U3.

[0016] The auxiliary circuit module includes a first auxiliary module connected to one end of the inductor L1 and the inductor L2 respectively, a second auxiliary module arranged in parallel with the on-off connection points R1+ and R1-, a third auxiliary module arranged between the second auxiliary module and the capacitor C2, and a fourth auxiliary module arranged in parallel with the capacitor C2; the first auxiliary module is a resistor R1, a resistor R2, a resistor R3 and a resistor R4 arranged in parallel, and connected to the channel analog switch U2 via the on-off connection points I1+ and I1-; the second auxiliary module is a resistor R10 and a resistor R11 arranged in parallel, the on-off connection points V1+ and V1- of the resistor R10 are connected to the channel analog switch U2, and the on-off connection points I2+ and I2- of the resistor R11 are connected to the channel analog switch U2. I2- is connected to the channel analog switch U2; the third auxiliary module is a power supply REF3_3, a diode D2 and a resistor R5 arranged in series, and the on-off connection points R2+ and R2- between the power supply REF3_3 and the diode D2 are connected to the channel analog switch U3; the fourth auxiliary module is a resistor R7, a resistor R8 and a resistor R9 arranged in parallel, the on-off connection points V2+ and V2- of the resistor R7 are connected to the channel analog switch U2, the on-off connection points I3+ and I3- of the resistor R8 are connected to the channel analog switch U3, and the on-off connection points R3+ and R3- of the resistor R9 are connected to the channel analog switch U3.

[0017] The relay Repay model is APAN3105.

[0018] The model of the channel analog switch U2 and the channel analog switch U3 is SN74HC4066.

[0019] The identification and receiving method of the external sensor intelligent identification and receiving circuit includes: Step A. After the controller is powered on, the MCU controls the relay Repay to turn on, and at the same time controls the channel analog switch U3 to turn on and off the connection points R1+ and R1-; Step B. The input terminals AI+ and AI- receive external signals, and the output terminal ADI collects external analog signals converted by the signal judgment circuit module; If the voltage value of the external analog signal is not less than the threshold value M, the external signal is determined to be a voltage type signal; If the voltage value of the external analog signal is greater than 0 and less than the threshold M, the external signal is determined to be a current type signal; If the voltage value of the external analog signal is 0, the external signal is determined to be a resistance signal; Step C. After the external signal type is identified, the MCU controls the relay Repay to disconnect, and at the same time controls the channel analog switch U3 to disconnect the on-off connection points R1+ and R1-; C1. If the external signal is a voltage type signal, the MCU controls the channel analog switch U2 to turn on the on-off connection points V1+, V1- and the on-off connection points V2+, V2-;.

[0020] C2. If the external signal is a current type signal, the MCU controls the channel analog switch U2 and the channel analog switch U3 to respectively turn on and off the connection points I1+, I1-, the connection points I2+, I2-, and the connection points I3+, I3-; C3. If the external signal is a resistor type signal, the MCU controls the channel analog switch U3 to conduct the on-off connection points R1+, R1-, the on-off connection points R2+, R2-, and the on-off connection points R3+, R3-. The value range of the threshold M is 0.8-1.

[0021] During specific implementation, the external signal type of the air-conditioning refrigeration unit can be divided into voltage type, current type or resistance type. Specific implementation example: After the controller is powered on, the relay Repay is controlled to be turned on through the MCU pin, and the resistor R12 is connected to the signal sampling circuit. At the same time, the on-off connection points R1+ and R1- are controlled to be turned on, and ADI collects external analog signals. If the external signal is a current type (4-20mA) signal, the voltage range collected by ADI is 0.16V-0.8V, if the external signal is a voltage type (1-5V), the voltage range collected by ADI is 1-5V, and if the external signal is a resistance type, the voltage collected by ADI is 0V. After determining the signal type, the MCU controls the relay Repay to be disconnected, and the relay is not allowed to be attracted again during the subsequent sampling process.

[0022] When the AI ​​sampling circuit of the air conditioning refrigeration unit controller is used for voltage signal sampling: MCU controls V1C and V2C to output high level, the on-off connection points V1+ and V1- controlled by the channel analog switch U2 are turned on, the on-off connection points V2+ and V2- are turned on, the resistor R10 is configured as 68K, and the resistor R7 is configured as 10K. The input terminals AI+ and AI- are connected to the external voltage signal source, the external voltage signal acts on the resistor R10 and the resistor R7, the resistor R10 and the resistor R7 are divided, the voltage at the output terminal ADI pin is the divided voltage value of the resistor R7, the output terminal ADI signal is input to the ADC sampling chip, the sampling chip converts the analog quantity into a digital quantity and transmits it to the CPU of the air conditioning controller, the CPU calculates the voltage value of the external signal source after calculation and processing.

[0023] When the AI ​​sampling circuit of the air-conditioning refrigeration unit controller is used for current signal sampling: MCU controls I1C, I2C and I3C to output high level, channel analog switch U2 controls the on-off connection points I1+ and I1- to be turned on, on-off connection points I2+ and I2- to be turned on, channel analog switch U3 controls the on-off connection points I3+ and I3- to be turned on, resistor R11 is configured as 120KΩ; resistor R8 is configured as 130K ohms; resistors R1, R2, R3 and R4 are configured as 1KΩ, and the organization is 250Ω after parallel connection. The input terminals AI+ and AI- are connected to an external current signal source, and the external current signal acts on resistors R1, R2, R3, R4, R11 and R8. Resistors R1, R2, R3, R4 are connected in parallel with resistors R11 and R8, so the voltage generated by resistors R1, R2, R3, R4 is the same as the voltage generated by resistors R11 and R8. Resistors R11 and R8 divide the voltage, and the voltage at the output terminal ADI pin is the divided voltage value of resistor R8. The output terminal ADI signal is input into the ADC sampling chip, and the sampling chip converts the analog quantity into a digital quantity and transmits it to the CPU of the air conditioner controller. The CPU calculates the current value of the external signal source after calculation and processing.

[0024] When the AI ​​sampling circuit of the air-conditioning refrigeration unit controller is used for resistive signal sampling: MCU controls R1C, R2C and R3C to output high level, the on-off connection points R1+ and R1- controlled by the channel analog switch U3 are turned on, the on-off connection points R2+ and R2- are turned on, and the on-off connection points R3+ and R3- are turned on; resistor R12 is configured to 0Ω; resistor R9 is configured to 100KΩ; resistor R5 is configured to 10KΩ. The input terminals AI+ and AI- are connected to an external resistance signal source, the external resistor and resistor R9 are connected in parallel, resistor R5 is connected in series with the external resistor and resistor R9, the REF3_3 power supply (3.3V) acts on resistor R5, resistor R9 and the external resistor, resistor R9 and the external resistor are connected in parallel and then divided by resistor R5, the voltage at the output terminal ADI pin is the divided voltage value after resistor R9 and the external resistor are connected in parallel, the output terminal ADI signal is input into the ADC sampling chip, the sampling chip converts the analog quantity into a digital quantity and transmits it to the CPU of the air conditioner controller, the CPU calculates the resistance value of the external signal source after calculation and processing.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An external sensor intelligent identification receiving circuit for an air conditioning refrigeration unit, connected between the external sensor and the MCU of the air conditioning refrigeration unit controller, the intelligent identification receiving circuit comprises input terminals AI+, AI- and output terminal ADI, characterized in that: A signal judgment circuit module is arranged between the input terminals AI+, AI- and the output terminal ADI. An auxiliary circuit module cooperating with the signal judgment circuit with the aid of a channel analog switch U2 and a channel analog switch U3 is also arranged in the intelligent identification receiving circuit. The signal judgment circuit module and the auxiliary circuit module are connected and disconnected with the aid of the channel analog switch U2 and the channel analog switch U3 to form a voltage-type receiving circuit, a current-type receiving circuit or a resistance-type receiving circuit.

2. The external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit according to claim 1 is characterized in that: The signal judgment circuit module includes a relay Repay and a resistor R12 connected in parallel and in series between the input terminals AI+ and AI-, a voltage stabilizing diode D1 and a capacitor C1 connected in parallel with the relay Repay and the resistor R12, an inductor L1 and an inductor L2 connected at both ends of the capacitor C1 respectively, a capacitor C2 whose two ends are connected to the inductor L1 and the inductor L2 respectively, a capacitor C3 and a resistor R6 connected in parallel and in series with the capacitor C2, and on-off connection points R1+ and R1- arranged between the inductor L1 and the capacitor C2, the output terminal ADI is connected between the capacitor C3 and the resistor R6, one end of the capacitor C2 is connected to GND, the control end of the relay Repay is connected to the MCU, and the on-off connection points R1+ and R1- are connected to the channel analog switch U3.

3. The external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit according to claim 2 is characterized in that: The auxiliary circuit module includes a first auxiliary module connected to one end of the inductor L1 and the inductor L2 respectively, a second auxiliary module arranged in parallel with the on-off connection points R1+ and R1-, a third auxiliary module arranged between the second auxiliary module and the capacitor C2, and a fourth auxiliary module arranged in parallel with the capacitor C2; the first auxiliary module is a resistor R1, a resistor R2, a resistor R3 and a resistor R4 arranged in parallel, and connected to the channel analog switch U2 via the on-off connection points I1+ and I1-; the second auxiliary module is a resistor R10 and a resistor R11 arranged in parallel, the on-off connection points V1+ and V1- of the resistor R10 are connected to the channel analog switch U2, and the on-off connection points I2+ and I2- of the resistor R11 are connected to the channel analog switch U2. I2- is connected to the channel analog switch U2; the third auxiliary module is a power supply REF3_3, a diode D2 and a resistor R5 arranged in series, and the on-off connection points R2+ and R2- between the power supply REF3_3 and the diode D2 are connected to the channel analog switch U3; the fourth auxiliary module is a resistor R7, a resistor R8 and a resistor R9 arranged in parallel, the on-off connection points V2+ and V2- of the resistor R7 are connected to the channel analog switch U2, the on-off connection points I3+ and I3- of the resistor R8 are connected to the channel analog switch U3, and the on-off connection points R3+ and R3- of the resistor R9 are connected to the channel analog switch U3.

4. The external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit according to claim 1, characterized in that: The relay Repay model is APAN3105.

5. The external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit according to claim 1, characterized in that: The model of the channel analog switch U2 and the channel analog switch U3 is SN74HC4066.

6. The external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit according to claim 3, characterized in that: The identification and receiving method of the external sensor intelligent identification and receiving circuit includes: Step A. After the controller is powered on, the MCU controls the relay Repay to turn on, and at the same time controls the channel analog switch U3 to turn on and off the connection points R1+ and R1-; Step B. The input terminals AI+ and AI- receive external signals, and the output terminal ADI collects external analog signals converted by the signal judgment circuit module; If the voltage value of the external analog signal is not less than the threshold value M, the external signal is determined to be a voltage type signal; If the voltage value of the external analog signal is greater than 0 and less than the threshold M, the external signal is determined to be a current type signal; If the voltage value of the external analog signal is 0, the external signal is determined to be a resistance signal; Step C. After the external signal type is identified, the MCU controls the relay Repay to disconnect, and at the same time controls the channel analog switch U3 to disconnect the on-off connection points R1+ and R1-; C1. If the external signal is a voltage type signal, the MCU controls the channel analog switch U2 to conduct the on-off connection points V1+, V1- and the on-off connection points V2+, V2-; C2. If the external signal is a current type signal, the MCU controls the channel analog switch U2 and the channel analog switch U3 to respectively turn on and off the connection points I1+, I1-, the connection points I2+, I2-, and the connection points I3+, I3-; C3. If the external signal is a resistor type signal, the MCU controls the channel analog switch U3 to turn on and off the connection points R1+, R1-, the connection points R2+, R2-, and the connection points R3+, R3-.

7. The external sensor intelligent identification receiving circuit for an air-conditioning refrigeration unit according to claim 6, characterized in that: The threshold M ranges from 0.8 to 1.

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