WO2022041890A1

WO2022041890A1 - Switching value acquisition circuit and method

Info

Publication number: WO2022041890A1
Application number: PCT/CN2021/096656
Authority: WO
Inventors: 庞吉耀; 陆华军
Original assignee: 南京磐能电力科技股份有限公司
Priority date: 2020-08-24
Filing date: 2021-05-28
Publication date: 2022-03-03
Also published as: CN111983298A; ZA202106320B; CN111983298B

Abstract

A switching value acquisition circuit. The circuit comprises a control power supply state detection loop, an MCU signal acquisition control loop, and at least one switching value acquisition loop; the switching value acquisition loop comprises a primary acquisition optocoupler (U3) and a secondary acquisition optocoupler (U2); and the MCU signal acquisition control loop is used for controlling, in response to level signals detected by the control power supply state detection loop, to disconnect the secondary acquisition optocoupler (U2) to acquire switching value signals only by the primary acquisition optocoupler (U3), or to enable both the secondary acquisition optocoupler (U2) and the primary acquisition optocoupler (U3) to acquire switching value signals. The switching value acquisition circuit can choose to output using one optocoupler or two optocouplers in parallel and acquire the control power supply voltage to dynamically change the transmission gain of the acquisition loop, such that noise suppression thresholds required by different control power supply voltages can be satisfied, and the design of the high potential side based on a passive device improves the reliability of the circuit system and reduces the cost of engineering debugging. Also provided is a switching value acquisition method.

Description

A switching value acquisition circuit and method

technical field

The invention relates to the technical field of industrial automation and relay protection, in particular to a switching value acquisition circuit and method.

Background technique

In the field of industrial automation and relay protection, in order to ensure the reliability of the control system, DC power supply is mostly used. When the capacity of the DC system is high, a lower control voltage is generally used to reduce the number of battery packs. For example, there are two kinds of control power supply often used in power field: 110V DC and 220V DC. In these systems, due to the dual requirements of collecting the state of the main equipment and anti-electromagnetic interference, all switching signals are powered by the control power supply, connected to the control device by the strong current, and then rectified, filtered, stepped down, and limited current. Then it is sent to the main control CPU after being isolated by the optocoupler, and then the switching value is collected.

In order to meet the needs of different control power supply voltages in engineering, it is often necessary to design two sets of different acquisition modules and use different voltage-reducing current-limiting circuits, which brings inconvenience to the production, debugging and on-site management of the switching value acquisition module. design and production costs.

At present, there are ADC sampling method, FPGA-based pulse width detection method, variable reference comparator method, etc. for the adaptive switching value acquisition method of control power supply system. Although these methods can solve the problem of switching value acquisition under different control power supply voltages to a certain extent However, there are also some shortcomings, such as complex system, troublesome debugging, poor circuit reliability, and difficulty in setting the threshold. Therefore, it is the primary problem to seek an adaptive switching value acquisition circuit and method with high potential side based on passive devices, simple circuit, high reliability and convenient engineering debugging.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a switching value acquisition circuit and method. According to the difference of the control power supply voltage, one group of optocoupler outputs or two groups of optocoupler parallel outputs are selected to realize the switching value acquisition. The loop transmission gain is adaptive.

To achieve the above object, the present invention adopts the following technical solutions to realize:

first:

The invention provides a switching quantity acquisition circuit, comprising a control power state detection circuit, an MCU signal acquisition control circuit and at least one switching quantity acquisition circuit; the switching quantity acquisition circuit comprises a main acquisition optocoupler and a secondary acquisition optocoupler;

The control power supply state detection circuit is used to detect the state of the control power supply supplying power for the switch signal;

The MCU signal acquisition control loop is used to control the disconnection of the sub-acquisition optocoupler according to the detected state of the control power supply, and only collect the switching signal through the main acquisition photocoupler, or to control the activation of the sub-acquisition photocoupler and the main acquisition photocoupler to jointly acquire the switch. quantity signal.

Further, the switch quantity acquisition loop further includes a controlled power switch, a shunt resistor and a first output resistor;

The shunt resistor is connected in parallel with the positive and negative poles of the input terminals of the main collection optocoupler, the positive pole of the input terminal of the main collection optocoupler is connected with the negative pole of the input terminal of the auxiliary collection optocoupler, and the negative pole of the input terminal of the main collection optocoupler is connected with the switch input terminal. ; The positive pole of the input terminal of the auxiliary collection optocoupler is connected to the control power supply;

The collector of the output end of the main collection optocoupler is connected to the low-potential side power supply VCC, and the MCU signal collection control loop controls the on-off of the output end collector of the sub-collection optocoupler and the low-potential side power supply VCC through the controlled power switch ;

The MCU signal collection control loop collects switching signals through the output end emitter of the main collection optocoupler, and the output end emitter of the main collection optocoupler is connected to the output end emitter of the auxiliary collection optocoupler and grounded through the first output resistor.

Further, the switching value acquisition loop further includes a first current limiting resistor, a first rectifier diode, a first reverse protection diode, a first voltage regulator tube and a second current limiting resistor;

The first current limiting resistor and the first rectifier diode are connected in series between the positive electrode of the control power supply and the positive electrode of the input end of the auxiliary collection optocoupler; the first voltage regulator tube and the second current limiting resistor are connected in series with the switch input end and the main collection optocoupler Between the negative poles of the input terminals;

The cathode of the first reverse protection diode is connected to the anode of the input terminal of the secondary collection optocoupler, and the anode of the first reverse protection diode is connected to the cathode of the input terminal of the main collection optocoupler.

Further, the controlled power switch includes a PNP triode and a base pull-up resistor of the PNP triode, an NPN triode and a base current limiting resistor of the NPN triode;

The base of the NPN triode is connected to the MCU signal acquisition control loop through the base current limiting resistor, the emitter of the NPN triode is grounded, and the collector of the NPN triode is connected to the base of the PNP triode;

The collector of the PNP triode is connected to the collector of the output end of the secondary collection optocoupler, the emitter of the PNP triode is connected to the low potential side power supply VCC, and the base of the PNP triode is connected through the base pull-up resistor. to the low potential side power supply VCC.

Further, the control power supply state detection loop includes a third current limiting resistor, a second rectifier diode, a second reverse protection diode, a second voltage regulator tube, a fourth current limiting resistor, a control power supply state acquisition optocoupler, and a second output resistance;

The positive pole of the control power supply is connected in series with a third current limiting resistor, and the second rectifier diode is connected to the positive pole of the input terminal of the control power supply state collection optocoupler; the negative pole of the control power supply is connected in series with the fourth current limiting resistor, the second voltage regulator tube and the control power supply state collection light The negative pole of the input terminal of the coupling is connected; the second reverse protection diode is connected in reverse parallel to the positive and negative terminals of the input terminal of the control power supply state acquisition optocoupler;

The output terminal collector of the control power state acquisition optocoupler is connected to the low potential side power supply VCC, and the output terminal emitter of the control power state acquisition optocoupler is grounded through the second output resistor, and is connected to the MCU signal acquisition control loop. Controls the power state acquisition port connection.

Further, when there are multiple switching quantity acquisition circuits, the collectors of the output terminals of the sub-collecting optocouplers in each switching quantity acquisition circuit are connected in parallel to the rear end of the same controlled power switch.

Further, the voltage regulation value U _z6 of the first voltage regulator satisfies: V _{c_l} >U _z6 >V _{c_l_th} , wherein V _{c_l_th} is the low-level threshold of the switching quantity when the control power supply voltage is V _{c_l} , and V _{c_l} is used by the control power supply. Voltage value at low supply voltage.

Further, the resistance constraints of the shunt resistor are:

Among them, V _{c_h_th} is the low level threshold value of the switching quantity when the control power supply voltage is V _{c_h} , V _{c_h} is the voltage value when the control power supply uses a high power supply voltage, U _z6 is the voltage regulation value of the first voltage regulator, and V _F3 is the main Collecting the forward turn-on voltage of the light-emitting tube of the optocoupler, R ₃ , R ₄ , and R ₆ are the resistance values of the first current limiting resistor, the second current limiting resistor, and the shunt resistor, respectively.

In a second aspect, a switching value acquisition method, the method includes the following steps:

Collect the status signal of the control power supply;

According to the status signal of the control power supply, control to disconnect the sub-collection optocoupler to collect the switch signal only through the main collection optocoupler, or control to enable the sub-collection optocoupler and the main collection optocoupler to collect the switch signal together.

Further, the method for disconnecting the secondary collection optocoupler includes the following steps:

The MCU signal acquisition control loop controls the shutdown of the PNP transistor by controlling the shutdown of the NPN transistor, and then disconnects the collector power supply of the secondary acquisition optocoupler, so that the secondary acquisition optocoupler stops working;

The method for turning on the secondary collection optocoupler includes the following steps:

The MCU signal acquisition control loop controls the opening of the PNP transistor by controlling the opening of the NPN transistor, and turns on the collector power supply of the output end of the auxiliary collection optocoupler, so that the emitter output of the auxiliary collection optocoupler is connected in parallel to the emitter of the main collection optocoupler.

Further, before collecting the control power status signal, first determine whether to use the software mode:

If so, use the preset software setting value to control the disconnection or opening of the secondary collection optocoupler;

If not, the control power state is collected, and the secondary collection optocoupler is controlled to be disconnected or turned on according to the control power state.

Compared with the prior art, the beneficial effects achieved by the present invention:

The switching value acquisition circuit provided by the present invention can detect the voltage state of the control power supply in real time, and according to different control power supply voltages, control to disconnect the secondary acquisition optocoupler and only collect the switching value signal through the main acquisition optical coupler, or control to enable the secondary acquisition optocoupler and the The main collection optocoupler collects the switching signal together;

The switching value acquisition circuit adopts the design of the main acquisition optocoupler, the auxiliary acquisition optocoupler and the controlled power switch. According to the different voltage levels of the control power supply, one set of optocoupler output or two sets of optocoupler parallel output can be selected to realize the acquisition loop. The transmission gain is dynamically changed to meet the noise suppression threshold required by different control power supply voltages;

In addition, the high-potential side of the present invention improves the reliability of the circuit system and reduces the engineering debugging cost based on the passive device design.

Description of drawings

FIG. 1 is a schematic diagram of a single-channel switch quantity acquisition according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a control power supply state detection according to an embodiment of the present invention;

3 is a schematic diagram of a complete multi-channel switch value acquisition according to an embodiment of the present invention;

FIG. 4 is a flowchart of a method for collecting a switching value according to an embodiment of the present invention;

FIG. 5 is a flow chart of the power supply control of the secondary acquisition loop according to an embodiment of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.

In the description of the present invention, it should be understood that the terms "center", "portrait", "horizontal", "top", "bottom", "front", "rear", "left", "right", " The orientation or positional relationship indicated by vertical, horizontal, top, bottom, inner, outer, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and The description is simplified rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", etc., may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

Example 1:

The embodiment of the present invention provides a switching quantity acquisition circuit, which includes a control power supply state detection circuit, an MCU signal acquisition control circuit, and at least one mining quantity acquisition circuit. Among them, the control power state detection circuit is used to detect the control power supply state, and output the state signal of the control power supply; the switch value acquisition circuit is used to collect the switch value; the MCU signal acquisition control circuit is used to receive the control power transmitted by the control power supply state detection circuit The power state signal is controlled, and the switch quantity acquisition circuit is controlled to collect the switch quantity signal according to the control power state signal.

As shown in Figure 1, the switching value acquisition loop includes a first current limiting resistor R3, a first rectifier diode V4, a first reverse protection diode V5, a first Zener tube V6, a second current limiting resistor R4, and a main collection optocoupler U3, secondary collection optocoupler U2, controlled power switch, shunt resistor R6 and first output resistor R8; wherein, the controlled power switch includes PNP transistor VT2 and base pull-up resistor R9 of PNP transistor VT2, NPN transistor VT1 and NPN The base current limiting resistor R10 of the triode VT1.

As shown in Figure 1, the specific connection relationship of the switching value acquisition loop is that one end of the first current limiting resistor R3 is connected to the positive pole of the control power supply, the other end is connected to the positive terminal A of the first rectifier diode V4, and the negative terminal K of the first rectifier diode V4 is connected. Connect the positive terminal A of the input terminal of the secondary collection optocoupler U2; the negative terminal K of the input terminal of the secondary collection optocoupler U2 is connected to the positive terminal A of the input terminal of the main collection optocoupler U3, and the negative terminal K of the input terminal of the main collection optocoupler U3 is It is connected to the negative terminal K of the first voltage regulator tube V6; one end of the second current limiting resistor R4 is connected to the switch input terminal, and the other end is connected to the positive terminal A of the first voltage regulator tube V6 to form a signal path on the high potential side. The negative terminal K of a reverse protection diode V5 is connected to the positive terminal A of the secondary collection optocoupler U2, and the negative terminal A of the first reverse protection diode V5 is connected to the negative K terminal of the input terminal of the main collection optocoupler U3 to realize the acquisition of In the loop, the reverse input voltage protection of the main collection optocoupler U3 and the secondary collection optocoupler U2, the shunt resistor R6 is connected in parallel with the positive A terminal and the negative K terminal of the main collection optocoupler U3.

Specifically, the output end emitter E of the sub-collection optocoupler U2 of the switching value collection circuit is connected with the output end emitter E of the main collection optocoupler U3, and the connection point is grounded through the first output resistor R8, and the low The switch output on the potential side is output through the emitter E of the output end of the main collection optocoupler U3.

Specifically, the output collector C of the main collection optocoupler U3 of the switching value collection circuit is directly connected to the low-potential side power supply VCC, while the output collector C of the auxiliary collection optocoupler U2 is connected to the PNP transistor VT2. The collector C , and the emitter E of the PNP transistor VT2 is connected to the low potential side power supply VCC, while the base B of the PNP transistor VT2 is connected to the low potential side power supply VCC through the base pull-up resistor R9.

Specifically, the emitter E of the NPN transistor VT1 in the switching value acquisition loop is grounded, the collector C is connected to the base B of the PNP transistor VT2, and the base B of the NPN transistor VT1 is connected to the MCU through its base current limiting resistor R10 The output IO pin CTRL of the signal acquisition control loop, the MCU signal acquisition control loop can control the on and off of the PNP transistor VT2 through this pin.

In the embodiment of the present invention, the control power supply state detection loop collects the state signal of the control power supply, where the state signal of the control power supply is a level signal; the control power supply state detection loop includes a third current limiting resistor R1, a second rectifier diode V1, The second reverse protection diode V2, the second voltage regulator tube V3, the fourth current limiting resistor R2, the control power supply state collection optocoupler U1 and the second output resistor R7.

As shown in Fig. 2, in this embodiment, one end of the third current limiting resistor R1 is connected to the positive pole of the control power supply, the other end is connected to the positive pole A terminal of the second rectifier diode V1, and the negative pole K terminal of the second rectifier diode V1 is connected to the control power supply state acquisition The positive terminal A of the input terminal of the optocoupler U1 is connected to the negative terminal K of the input terminal of the optocoupler U1, and the negative terminal K of the input terminal of the optocoupler U1 is connected to the negative terminal K of the second voltage regulator tube V3; Negative, the other end is connected to the positive terminal A of the second voltage regulator tube V3; the positive terminal A of the second reverse protection diode V2 is connected to the positive terminal K of the input terminal of the control power state acquisition optocoupler U1, and the second reverse protection diode The negative pole K of the diode V2 is connected to the negative pole A of the input terminal of the control power supply state collection optocoupler U1.

Specifically, the output end emitter E of the control power state acquisition optocoupler U1 of the control power state detection loop is connected to the ground through the second output resistor R7, and the output end collector C of the control power state acquisition optocoupler U1 is directly connected to the low potential The side power supply VCC, and the control power state output signal is output from the output end emitter E of the control power state acquisition optocoupler U1, and is connected to the input IO pin PWR of the MCU signal acquisition control loop.

As shown in FIG. 1 and FIG. 3 , the MCU signal acquisition control loop in the embodiment of the present invention includes the MCU and its auxiliary circuit, wherein the output signal of the control power state detection loop and the output signal of the switch value acquisition loop are respectively connected to the input IO of the MCU The pins PWR and DIN, and the output IO pin CTRL of the MCU is connected to one end of the base current limiting resistor R10 of the NPN triode VT1 in the switch quantity acquisition loop.

As shown in FIG. 3 , in the embodiment of the present invention, when there are multiple switching value acquisition circuits, the output terminal collectors of the auxiliary acquisition optocouplers in the output terminal collectors of the auxiliary acquisition optocouplers U2 of each switching quantity acquisition circuit are connected in parallel Connected to the back end of the same controlled power switch, it can also be understood as: the controlled power switch composed of the PNP transistor VT2 and the NPN transistor VT1 is shared by the acquisition channels of multiple digital acquisition circuits, and the assumption is that the same digital acquisition The switch quantity on the module uses the same control power supply. Specifically, the positive terminal of each switching value acquisition circuit is connected to the positive terminal of the control power supply, and the negative terminal of each switching value acquisition circuit is used as the switching value input terminal to obtain the switching value signal from the outside, which is collected by the switching value acquisition circuit and then input to the corresponding MCU. Input IO pin DIN.

The switching value acquisition circuit provided by the present invention selects to use one set of optocoupler outputs or two sets of optocoupler parallel outputs according to the different control power supply voltage levels, and dynamically changes the transmission gain of the acquisition loop by collecting the control power supply voltage state, which can meet different control requirements. The noise suppression threshold required by the power supply voltage, and the design of the high-potential side based on passive components further improves the reliability of the circuit system and reduces the cost of engineering debugging.

Specifically, in order to better realize the above-mentioned switching value acquisition circuit, the parameters of the components involved should be selected according to the difference between the two control power supply voltages in the project:

In an embodiment of the present invention, the control power supply state detection loop collects the state signal of the control power supply, where the state signal of the control power supply is a level signal, that is, a high level and a low level.

In the control power state detection loop shown in FIG. 2 , if the high control power supply voltage value is V _{c_h} , the corresponding control power state detection loop output signal is high level, and the low control power supply voltage value is V _{c_l} , which corresponds to The control power state detection loop output signal is low level. It should be noted that the high control power supply voltage and the low control power supply voltage in the present invention can be adjusted according to the actual situation by adjusting the components such as the second voltage regulator tube V3, the third current limiting resistor R1 and the fourth current limiting resistor R2 in the circuit. The determination of the high and low voltage ranges, here, the high control power supply voltage and the low control power supply voltage can also be understood as a relative comparison between voltages, and no specific numerical range is limited, so as to realize the technical solution of the present invention.

As shown in Figure 2, the selection principle of each component parameter of the control power state detection loop is as follows:

The selection principle of the voltage regulation value U _z3 of the second voltage regulator tube V3 is: V _{c_h} >U _z3 >V _{c_l} ,

The selection principle of the third current limiting resistor R1 and the fourth current limiting resistor R2 is to first ensure that when the high control power supply voltage is V _{c_h} , the forward current _IF flowing through the light-emitting tube of the control power supply state collection optocoupler U1 is as small as possible to To reduce power consumption, the second is to ensure the transmission gain of the loop, so that when the high control power supply voltage is V _{c_h} , the output of the control power state acquisition optocoupler U1 is high; in the control power state detection loop, the control power supply adopts a high control power supply voltage When the control power state acquisition optocoupler U1 is turned on, the output control power state signal is high level; when the control power supply adopts a low control power supply voltage; the control power state acquisition optocoupler U1 is turned off, and the output control power state signal is low level.

In the switch value acquisition circuit:

The selection principle of the voltage regulation value U _z6 of the first voltage regulator tube V6 is to ensure that when the low control power supply voltage is V _{c_l} , it satisfies the requirement of the low level threshold value V _{c_l_th} of the switching quantity (that is, when the input terminal voltage of the switching quantity is less than V _{c_l_th} , the acquisition circuit is reliable. Output low level): V _{c_l} >U _z6 >V _{c_l_th} ; the voltage of the first voltage regulator tube V6 can be lower than the low level threshold V _{c_l_th} of the switching quantity at the input terminal of the switching quantity (for example, close to 0, or the switching quantity input terminal is disconnected, When floating, etc.), it will not incorrectly output a high level due to instantaneous voltage fluctuations caused by changes in external factors (electric shock, static electricity, etc.); when the control power supply voltage V _{c_1} is low, the first Zener tube V6 can ensure that when the switching value input terminal Output high when the voltage exceeds V _{c_l_th} .

The selection principle of the resistance value of the shunt resistor R6 is to ensure that when the high control power supply voltage is V _{c_h} , it meets the requirement of the low level threshold V _{c_h_th} of the switching value (that is, when the input voltage of the switching value is less than V _{c_h_th} , the acquisition circuit can reliably output a low level, which needs to be Ensure that the light-emitting tube current of the main collection optocoupler U3 is close to 0), and the constraint conditions for the selection of the resistance value of the shunt resistor R6 are:

Among them, V _{c_h_th} corresponds to the threshold value at which the switching value acquisition loop reliably outputs a low level when the control power supply adopts a high control power supply voltage V _{c_h} , U _z6 corresponds to the voltage stabilization value of the first voltage regulator tube V6, and V _F3 corresponds to the main collection optocoupler U3. The forward turn-on voltage of the light-emitting tube, R ₃ , R ₄ , and R ₆ correspond to the resistance values of the first current limiting resistor R3 , the second current limiting resistor R4 , and the shunt resistor R6 . In this embodiment, the shunt resistor R6 performs current shunt. When the voltage at the input terminal of the switch value is less than the low level threshold of the switch value, the shunt resistor R6 makes the current flowing through the light-emitting tube of the main collection optocoupler U3 close to 0, which cannot make the main collection The phototransistor at the back end of the optocoupler is saturated and turned on, so that the output acquisition signal is low level.

The selection principle of the first current limiting resistor R3 and the second current limiting resistor R4 is to ensure that when the control power supply adopts a high control power supply voltage V _{c_h} , the power consumption of the acquisition loop is as low as possible while ensuring the circuit transmission gain.

The selection principle of the first output resistor R8 is to ensure that when the circuit has different control power supply voltages, the voltage of the switch input terminal (switch signal level) is lower than the allowable threshold of the system (V c_h_th when the control power supply voltage is high, and V _{c_h_th} when the control power supply voltage is low. When the voltage is V _{c_l_th} ), the output of the switch value acquisition loop is low level.

The PNP transistor VT2 is used as a controlled power switch. The selection principle is the lowest possible saturation conduction voltage drop, and the current parameter of the saturation conduction depends on the number of switching acquisition channels. The base pull-up resistor R9 of the PNP transistor VT2 It can ensure that the leakage current of the NPN triode VT1 in the circuit will not pull down the base voltage of VT2, and the controlled power switch composed of the PNP triode VT2 and the NPN triode VT1 is shared by multiple acquisition channels. The condition is that the digital value on the same digital value acquisition module uses the same control power supply.

Embodiment 2:

As shown in FIG. 4 , an embodiment of the present invention provides a switching value acquisition method, which includes the following steps:

Collect the status signal of the control power supply;

According to the status signal of the control power supply, disconnect or turn on the secondary collection optocoupler;

Control the disconnection of the sub-collection optocoupler to collect digital signals only through the main collection optocoupler, or control to enable the sub-collection optocoupler and the main collection optocoupler to jointly collect the digital signal.

Specifically, in an embodiment of the present invention, the state signal of the control power supply is collected by the control power supply state detection loop, and the state signal of the control power supply is a level signal. If the control power supply state signal is at a high level, the MCU turns off the NPN by controlling The triode is used to control the closing of the PNP triode, and then disconnect the secondary collection optocoupler;

If the control power status signal is low level, the MCU controls the turning on of the NPN transistor to turn on the PNP transistor, so that the secondary collection optocoupler output is connected in parallel with the main collection optocoupler output to improve the transmission gain of the switching value collection circuit.

As an embodiment of the present invention, as shown in FIG. 3 , the schematic circuit of the multi-channel switch value acquisition control of the present invention, the switch value input channel 1 is taken as an example to illustrate the switch value acquisition operation:

When a low control power supply voltage is used, the level signal output by the control power state detection loop is low level, the MCU signal acquisition control loop responds to the above low level signal, and controls the NPN transistor VT1 to turn on, and then controls the PNP transistor VT2 to turn on, Realize the parallel output of the main collection optocoupler U3 and the auxiliary collection optocoupler U2 in the switching value collection circuit, so that the transmission gain of the collection circuit increases, and the switching value status signal is determined by the parallel output of the main collection optocoupler U3 and the auxiliary output optocoupler U2;

When a high control power supply voltage is used, the level signal output by the control power state detection loop is high level, the MCU signal acquisition control loop responds to the above high level signal, and controls the NPN transistor VT1 to close, and then controls the PNP transistor VT2 to close, the switch The quantity status signal is determined by the output of the main acquisition optocoupler U3.

As an embodiment of the present invention, as shown in Figure 5, before collecting the control power state signal, first determine whether to use the software mode:

If not, the state of the control power is collected and controlled to disconnect or turn on the secondary collection optocoupler according to the result.

Specifically, in an embodiment of the present invention, the MCU signal acquisition control loop first checks the MCU setting value state after starting:

If the software mode is set in advance, the output state of the control power detection loop is ignored, and the output IO pin CTRL is driven according to the pre-set value, namely:

If the pre-configured system adopts a low control power supply voltage, the NPN transistor VT1 is controlled to be turned on, and then the PNP transistor VT2 is controlled to be turned on to realize the parallel output of the main collection optocoupler U3 and the auxiliary collection optocoupler U2 in the switching value collection circuit;

If the pre-configured system adopts a high control power supply voltage, the MCU controls the NPN transistor VT1 to turn off, and then controls the PNP transistor VT2 to turn off, and the switch value acquisition loop only uses the output of the main acquisition optocoupler U3.

If the software mode is not used, the control power supply state signal is obtained by the control power supply detection circuit, and the auxiliary acquisition optocoupler is controlled to be turned on or off according to the control power supply voltage state.

Specifically, in an embodiment of the present invention, if the control power state signal is at a low level, the MCU obtains the low level signal, and inverts the signal to a high level, and turns on the NPN transistor VT1 through the output IO pin CTRL, and then turns on the NPN transistor VT1. Turn on the PNP transistor VT2, so that the collector of the output terminal of the auxiliary collection optocoupler is connected to the power supply, and the switch value collection circuit is output in parallel by the main collection optocoupler U3 and the auxiliary collection optocoupler U2; similarly, if the control power status signal is high, And the inversion is low level, and the NPN transistor VT1 is turned off by the output IO pin CTRL, and then the PNP transistor VT2 is turned off, so that the collector of the output end of the auxiliary collection optocoupler U2 is disconnected from the power supply, and the switching value collection loop is controlled by the main collection light. Coupling U3 separate output.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims

A switching value acquisition circuit, characterized in that it includes a control power supply state detection circuit, an MCU signal acquisition control circuit and at least one switching value acquisition circuit; the switching value acquisition circuit includes a main acquisition optocoupler and a secondary acquisition optocoupler;

The control power supply state detection circuit is used to detect the state of the control power supply supplying power for the switch signal;

The MCU signal acquisition control loop is used to control the disconnection of the sub-acquisition optocoupler according to the detected state of the control power supply, and only collect the switching signal through the main acquisition photocoupler, or to control the activation of the sub-acquisition photocoupler and the main acquisition photocoupler to jointly acquire the switch. quantity signal.
The switch quantity acquisition circuit according to claim 1, wherein the switch quantity acquisition circuit further comprises a controlled power switch, a shunt resistor and a first output resistor;

The shunt resistor is connected in parallel with the positive and negative poles of the input terminals of the main collection optocoupler, the positive pole of the input terminal of the main collection optocoupler is connected with the negative pole of the input terminal of the auxiliary collection optocoupler, and the negative pole of the input terminal of the main collection optocoupler is connected with the switch input terminal. ; The positive pole of the input terminal of the auxiliary collection optocoupler is connected to the control power supply;

The collector of the output end of the main collection optocoupler is connected to the low-potential side power supply, and the MCU signal collection control loop controls the on-off of the output end collector of the sub-collection optocoupler and the low-potential side power supply through the controlled power switch. ;

The MCU signal collection control loop collects switching signals through the output end emitter of the main collection optocoupler, and the output end emitter of the main collection optocoupler is connected to the output end emitter of the auxiliary collection optocoupler and grounded through the first output resistor.
The switching value acquisition circuit according to claim 2, wherein the switching value acquisition circuit further comprises a first current limiting resistor, a first rectifier diode, a first reverse protection diode, a first voltage regulator and a second Current limiting resistor;

The first current limiting resistor and the first rectifier diode are connected in series between the positive electrode of the control power supply and the positive electrode of the input end of the auxiliary collection optocoupler; the first voltage regulator tube and the second current limiting resistor are connected in series with the switch input end and the main collection optocoupler Between the negative poles of the input terminals;

The cathode of the first reverse protection diode is electrically connected to the anode of the input terminal of the secondary collection optocoupler, and the anode of the first reverse protection diode is electrically connected to the cathode of the input terminal of the main collection optocoupler.
The switching quantity acquisition circuit according to claim 2, wherein the controlled power switch comprises a PNP triode, a base pull-up resistor of the PNP triode, an NPN triode and a base current limiting resistor of the NPN triode;

The base of the NPN triode is connected to the MCU signal acquisition control loop through the base current limiting resistor, the emitter of the NPN triode is grounded, and the collector of the NPN triode is connected to the base of the PNP triode;

The collector of the PNP triode is connected to the collector of the output end of the secondary collection optocoupler, the emitter of the PNP triode is connected to the low-potential side power supply, and the base of the PNP triode is connected to the base pull-up resistor. Low potential side power supply.
The switching value acquisition circuit according to claim 1, wherein the control power supply state detection loop comprises a third current limiting resistor, a second rectifier diode, a second reverse protection diode, a second voltage regulator, a fourth Current limiting resistor, control power state acquisition optocoupler and second output resistor;

The positive pole of the control power supply is connected in series with the third current limiting resistor, the second rectifier diode is electrically connected to the positive pole of the input terminal of the control power supply state acquisition optocoupler; the negative pole of the control power supply is connected in series with the fourth current limiting resistor, the second voltage regulator tube and the control power supply state acquisition The negative pole of the input end of the optocoupler is electrically connected; the second reverse protection diode is connected in reverse parallel to both ends of the positive and negative poles of the input end of the optocoupler for controlling the power supply state collection;

The collector of the output end of the control power state acquisition optocoupler is connected to the low potential side power supply, and the emitter of the output end of the control power state acquisition optocoupler is grounded through the second output resistor, and is connected with the control of the MCU signal acquisition control loop. Power status collection port connection.
The switching value acquisition circuit according to claim 2, wherein when there are multiple switching value acquisition circuits, the output terminal collectors of the sub-collecting optocouplers in each switching value acquisition circuit are connected in parallel after the same controlled power switch. end.
The switching value acquisition circuit according to claim 3, wherein the voltage regulation value U z6 of the first voltage regulator satisfies: V c_l >U z6 >V c_l_th , wherein V c_l_th is when the control power supply voltage is V c_l The low level threshold of the switching quantity, V c_l is the voltage value when the control power supply uses a low power supply voltage.
The switching value acquisition circuit according to claim 3, wherein the resistance constraint condition of the shunt resistor is:

Among them, V c_h_th is the low level threshold value of the switching quantity when the control power supply voltage is V c_h , V c_h is the voltage value when the control power supply uses a high power supply voltage, U z6 is the voltage regulation value of the first voltage regulator, and V F3 is the main Collecting the forward turn-on voltage of the light-emitting tube of the optocoupler, R 3 , R 4 , and R 6 are the resistance values of the first current limiting resistor, the second current limiting resistor, and the shunt resistor, respectively.
A switching value acquisition method, characterized in that the method comprises the following steps:

Collect the status signal of the control power supply;

According to the status signal of the control power supply, control to disconnect the sub-collection optocoupler to collect the switch signal only through the main collection optocoupler, or control to enable the sub-collection optocoupler and the main collection optocoupler to collect the switch signal together.
The switching quantity collection method according to claim 9, wherein the method for disconnecting the secondary collection optocoupler comprises the following steps:

The MCU signal acquisition control loop controls the shutdown of the PNP transistor by controlling the shutdown of the NPN transistor, and then disconnects the collector power supply of the secondary acquisition optocoupler, so that the secondary acquisition optocoupler stops working;

The method for turning on the secondary collection optocoupler includes the following steps:

The MCU signal acquisition control loop controls the opening of the PNP transistor by controlling the opening of the NPN transistor, and turns on the collector power supply of the output end of the auxiliary collection optocoupler, so that the emitter output of the auxiliary collection optocoupler is connected in parallel to the emitter of the main collection optocoupler.
The switching value acquisition method according to claim 9, wherein, before collecting the control power supply status signal, first determine whether to use the software mode:

If so, use the preset software setting value to control the disconnection or opening of the secondary collection optocoupler;

If not, the control power state is collected, and the secondary collection optocoupler is controlled to be disconnected or turned on according to the control power state.