CN212486474U - Remote alternating current-direct current switch signal matcher - Google Patents
Remote alternating current-direct current switch signal matcher Download PDFInfo
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- CN212486474U CN212486474U CN202020825738.2U CN202020825738U CN212486474U CN 212486474 U CN212486474 U CN 212486474U CN 202020825738 U CN202020825738 U CN 202020825738U CN 212486474 U CN212486474 U CN 212486474U
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Abstract
The invention discloses a remote alternating current-direct current Switch signal matcher which is suitable for a remote conversion circuit for matching direct current or alternating current reference signals to represent the on-off of a Switch. The remote alternating current and direct current switch signal matcher provided by the invention adopts the technology that an alternating current and direct current constant current source is not influenced by the magnitude of series impedance, and is suitable for alternating current control and direct current control; the device is not only suitable for short-range lines, but also particularly suitable for long-range lines; the switch overcomes the defect that the switch on-off signals can not be transmitted in a long distance in the prior art, and adds a technical means for preventing external electromagnetic interference in the long-distance transmission process.
Description
Technical Field
The invention relates to the field of electrical control, in particular to a remote alternating current and direct current switch signal matcher which is suitable for a remote conversion circuit for matching direct current or alternating current reference signals to represent on-off of a switch.
Background
In the field of electrical control, mechanical switches or electrical appliances with equivalent mechanical switches are widely applied, the mechanical switches or the electrical appliances with equivalent mechanical switches are connected in a circuit through a circuit, the on-off action of the mechanical switches can generate related control signals to an indicator or a controller, and the circuit is a channel and a medium for signal transmission, so that accurate and reliable on-off signal transmission of the switches is of great importance.
The inventor discovers that in the process of implementing the embodiment of the invention:
if the circuit between the mechanical switch or the electrical appliance with the equivalent mechanical switch function and the indicator or the controller is short, the accurate and reliable target can be conveniently achieved by adopting the metal conducting wire to transmit the on-off signal of the switch; however, when the cable is used in a line with the length of dozens of meters to hundreds of meters, the signal transmission performance is disorderly, and the normal operation is difficult; the first one is that the equivalent resistance of the long-distance line must be considered in the signal transmission process, the equivalent impedance of the line is in direct proportion to the length of the line, the contact impedance of the electric contact of the mechanical switch or the equivalent mechanical switch is the contact impedance when the electric contact is closed, if the equivalent impedance of the line is far greater than the contact impedance of the contact, according to the voltage division principle, the voltage drop on the electric contact of the mechanical switch or the equivalent mechanical switch can be ignored, when the electric contact is disconnected with the electric contact, the voltage amplitude value measured at the input end of the indicator or the controller is almost the same, namely the on-off state of the electric contact is indistinguishable, and the line cannot accurately transmit the on-off signal of the switch; secondly, in the presence of external electromagnetic interference, the larger the line equivalent impedance is, the longer the line is, the more easily the line passively generates induced voltage, and the more easily the line receives external differential mode interference or common mode interference, that is, the line generates disordered on-off signals of the switch, thereby causing signal indication disorder and the adverse effect of misoperation of the controller.
Therefore, a remote alternating current-direct current switch signal matching device is currently absent in the field of electrical control.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a remote alternating current and direct current switch signal matcher which is suitable for matching a direct current or alternating current reference signal to represent a remote conversion circuit for switching on and off a switch.
The technical scheme adopted by the invention is as follows:
the device comprises an input end Switch _ in, an output end Switch _ out, a reference signal input end Vref and an AC/DC switching signal matching module; the input end Switch _ in is provided with a pair of wiring terminals and is mainly used for connecting a mechanical Switch or an electrical appliance with an equivalent mechanical Switch;
the output end Switch _ out is connected with an indicator or a controller which is used for receiving a matched direct current or alternating current reference signal to represent the on-off of the Switch; the reference signal input end Vref is used for matching a direct current or alternating current reference signal, and when the on-off of a switch needs to be represented by high and low level changes, the direct current reference signal is matched; when the on-off of the switch needs to be represented by the on-off of an alternating current waveform, an alternating current reference signal is matched; the alternating current-direct current Switch signal matching module is used for receiving the signals of the input end Switch _ in and the reference signal input end Vref, converting the signals into corresponding signals after circuit conversion, and sending the signals to the output end Switch _ out; the alternating current-direct current Switch signal matching module comprises an alternating current-direct current constant current source, a dummy load and an adjusting resistor, wherein the input end of the alternating current-direct current constant current source is connected with the reference signal input end Vref, the output end of the alternating current-direct current constant current source is respectively connected with one end of the input end Switch _ in and one end of the dummy load, the other end of the dummy load is respectively connected with the alternating current-direct current constant current source GND, one end of the adjusting resistor and one end of the output end Switch _ out, the other end of the input end Switch _ in is respectively connected with the other end of the adjusting resistor and the other end of the output end Switch _ out, and the adjusting resistor is used.
The loop formed by the AC/DC constant current source, the line, the electrical appliance of the mechanical switch or the equivalent mechanical switch and the adjusting resistor can not be influenced by the resistance of the line, except that the electrical appliance of the mechanical switch or the equivalent mechanical switch is disconnected without current, as long as the mechanical switch or the equivalent mechanical electrical appliance is closed, the loop must flow current, and the on/off of the electrical appliance of the mechanical switch or the equivalent mechanical switch can be accurately reflected by detecting whether the current flows on the adjusting resistor, namely according to whether voltage drop is generated on the adjusting resistor, so that the transmission of the on/off signal of the switch is finally realized; in addition, the other loop formed by the AC/DC constant current source and the dummy load is an open-circuit protection provided for the AC/DC constant current source.
Further, the dummy load is a fixed resistor or an adjustable resistor, and may also be an electronic load with an equivalent fixed resistor or an equivalent adjustable resistor function.
Further, the adjusting resistor is a fixed resistor or an adjustable resistor, and can also be an electronic load with the function of an equivalent fixed resistor or an equivalent adjustable resistor.
Further, the alternating current-direct current constant current source is a circuit formed by an operational amplifier.
Further, the alternating current-direct current constant current source comprises an operational amplifier U1, an operational amplifier U2, an operational amplifier U3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a constant current preset resistor RS and an adjustable resistor RT; the resistor R5 is the dummy load, and the adjustable resistor RT is the adjusting resistor;
the non-inverting input terminal U1a of the operational amplifier U1 is connected with the reference signal input terminal Vref, the inverting input terminal U1b of the operational amplifier U1 is respectively connected with the output terminal of the operational amplifier U1 and one end of the resistor R3, and the other end of the resistor R3 is respectively connected with one end of the resistor R4 and the non-inverting input terminal U2a of the operational amplifier U2; the inverting input end U2b of the operational amplifier U2 is respectively connected with one end of a resistor R1 and one end of a resistor R2, and the other end of the resistor R1 is connected with an alternating current-direct current constant current source GND; the other end of the resistor R2 is respectively connected with the output end of the operational amplifier U2 and one end of the constant current preset resistor RS; the other end of the constant current preset resistor RS is respectively connected with one end of a resistor R5, one end of the input end Switch _ in and the non-inverting input end U3a of the operational amplifier U3, and the inverting input end U3b of the operational amplifier U3 is respectively connected with the output end of the operational amplifier U3 and the other end of the resistor R4; the other end of the input end Switch _ in is respectively connected with one end of an adjustable resistor RT and one end of the output end Switch _ out; the other end of the output end Switch _ out is connected with the other end of the adjustable resistor RT, the other end of the resistor R5 and the alternating current-direct current constant current source GND respectively.
Further, a first-stage voltage reduction module and a voltage reduction module signal input end Vref-in are sequentially connected before the reference signal input end Vref for reducing the voltage amplitude of the reference signal.
Furthermore, the voltage reduction module is a three-terminal adjustable resistor, one fixed end of the voltage reduction module is connected with a signal input end Vref-in of the voltage reduction module, the other fixed end of the voltage reduction module is connected with an alternating current-direct current constant current source GND, and the adjustable end of the voltage reduction module is connected with a reference signal input end Vref.
The remote alternating current and direct current switch signal matcher has the advantages that the technology that an alternating current and direct current constant current source is not influenced by the magnitude of series impedance is adopted, so that the remote alternating current and direct current switch signal matcher is not only suitable for alternating current control, but also suitable for direct current control; the device is not only suitable for short-range lines, but also particularly suitable for long-range lines; the switch overcomes the defect that the switch on-off signals can not be transmitted in a long distance in the prior art, and adds a technical means for preventing external electromagnetic interference in the long-distance transmission process.
Drawings
Fig. 1 is a schematic diagram of a prior art remote switch application.
Fig. 2 is a typical schematic diagram of a remote ac/dc switching signal matcher according to the present invention.
Fig. 3 is an equivalent schematic diagram of the dummy load and the trimming resistor.
Fig. 4 is an embodiment of a remote ac/dc switch signal matcher according to the present invention.
FIG. 5 is a schematic diagram of a buck module.
FIG. 6 is one embodiment of a buck module.
Fig. 7 is a waveform diagram of the output Switch _ out when the reference signal input terminal Vref matches the dc signal.
Fig. 8 is a waveform diagram of the output Switch _ out when the reference signal input terminal Vref matches the ac signal.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, specific embodiments thereof are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.
As shown in fig. 1, which is a schematic diagram of a remote switch in the prior art, it can be seen that an equivalent resistance R of a long-distance line must be considered in a signal transmission process, the equivalent resistance R of the line is in direct proportion to the length of the line, contact impedances of electrical contacts of a mechanical switch or an equivalent mechanical switch are all present when the electrical contacts are closed, if the equivalent resistance R of the line is much greater than the contact impedance of the contacts, according to a voltage division principle, a voltage drop at the electrical contacts of the mechanical switch or the equivalent mechanical switch is negligible, when the electrical contacts are disconnected, a voltage amplitude measured at an input end of an indicator or a controller is almost the same, that is, an on-off state of the electrical contact is indistinguishable, and the line cannot accurately; in addition, under the condition of external electromagnetic interference, the larger the line equivalent impedance R is, the longer the line is, the more easily the line passively generates induced voltage, and the more easily the line is subjected to external differential mode interference or common mode interference, that is, disordered on-off signals of the switch can be generated on the line, and finally, the serious consequence of corresponding misoperation can be caused.
Fig. 2 is a typical schematic diagram of a remote ac/dc switching signal matcher, which includes an input Switch _ in, an output Switch _ out, a reference signal input Vref, and an ac/dc switching signal matching module;
the input end Switch _ in is provided with a pair of wiring terminals and is mainly used for connecting a mechanical Switch or an electrical appliance with an equivalent mechanical Switch;
the output end Switch _ out is connected with an indicator or a controller which is used for receiving a matched direct current or alternating current reference signal to represent the on-off of the Switch; the reference signal input end Vref is used for matching a direct current or alternating current reference signal, and when the on-off of a switch needs to be represented by high and low level changes, the direct current reference signal is matched; when the on-off of the switch needs to be represented by the on-off of an alternating current waveform, an alternating current reference signal is matched; the alternating current-direct current Switch signal matching module is used for receiving the signals of the input end Switch _ in and the reference signal input end Vref, converting the signals into corresponding signals after circuit conversion, and sending the signals to the output end Switch _ out; the alternating current-direct current Switch signal matching module comprises an alternating current-direct current constant current source, a dummy load and an adjusting resistor, wherein the input end of the alternating current-direct current constant current source is connected with the reference signal input end Vref, the output end of the alternating current-direct current constant current source is respectively connected with one end of the input end Switch _ in and one end of the dummy load, the other end of the dummy load is respectively connected with the alternating current-direct current constant current source GND, one end of the adjusting resistor and one end of the output end Switch _ out, the other end of the input end Switch _ in is respectively connected with the other end of the adjusting resistor and the other end of the output end Switch _ out, and the adjusting resistor is used.
The loop formed by the AC/DC constant current source, the line, the electrical appliance of the mechanical switch or the equivalent mechanical switch and the adjusting resistor can not be influenced by the resistance of the line, except that the electrical appliance of the mechanical switch or the equivalent mechanical switch is disconnected without current, as long as the mechanical switch or the equivalent mechanical electrical appliance is closed, the loop must flow current, and the on/off of the electrical appliance of the mechanical switch or the equivalent mechanical switch can be accurately reflected by detecting whether the current flows on the adjusting resistor, namely according to whether voltage drop is generated on the adjusting resistor, so that the transmission of the on/off signal of the switch is finally realized; in addition, the other loop formed by the AC/DC constant current source and the dummy load is an open-circuit protection provided for the AC/DC constant current source.
Fig. 3 is an equivalent schematic diagram of the dummy load and the adjusting resistor, where the dummy load and the adjusting resistor are fixed resistors or adjustable resistors, and may also be electronic loads with functions of equivalent fixed resistors or equivalent adjustable resistors.
Fig. 4 shows an embodiment of a remote ac/dc switching signal matcher according to the present invention, wherein the ac/dc constant current source is a circuit formed by operational amplifiers, and the ac/dc constant current source includes an operational amplifier U1, an operational amplifier U2, an operational amplifier U3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a constant current preset resistor RS, and an adjustable resistor RT; the resistor R5 is the dummy load, and the adjustable resistor RT is the adjusting resistor;
the non-inverting input terminal U1a of the operational amplifier U1 is connected with the reference signal input terminal Vref, the inverting input terminal U1b of the operational amplifier U1 is respectively connected with the output terminal of the operational amplifier U1 and one end of the resistor R3, and the other end of the resistor R3 is respectively connected with one end of the resistor R4 and the non-inverting input terminal U2a of the operational amplifier U2; the inverting input end U2b of the operational amplifier U2 is respectively connected with one end of a resistor R1 and one end of a resistor R2, and the other end of the resistor R1 is connected with an alternating current-direct current constant current source GND; the other end of the resistor R2 is respectively connected with the output end of the operational amplifier U2 and one end of the constant current preset resistor RS; the other end of the constant current preset resistor RS is respectively connected with one end of a resistor R5, one end of the input end Switch _ in and the non-inverting input end U3a of the operational amplifier U3, and the inverting input end U3b of the operational amplifier U3 is respectively connected with the output end of the operational amplifier U3 and the other end of the resistor R4; the other end of the input end Switch _ in is respectively connected with one end of an adjustable resistor RT and one end of the output end Switch _ out; the other end of the output end Switch _ out is connected with the other end of the adjustable resistor RT, the other end of the resistor R5 and the alternating current-direct current constant current source GND respectively.
The operational amplifier U1 is a voltage follower circuit for increasing the input impedance, decreasing the output impedance and reducing the distortion of the signal; the operational amplifier U3 is also a voltage follower circuit for ensuring the output current I of the operational amplifier U20The current almost completely flows to the load, so that the constant current effect is better, and the parameters in the circuit can be stabilized; output current I in a circuit0The relationship with the input voltage Ui is derived as follows:
setting a resistance
R1＝R2＝R3＝R4 (1)
Because the operational amplifier U3 is a voltage follower connection, there are
U02＝U3a (2)
According to the principle of superposition, then
The operational amplifier U2 is an in-phase proportional amplifier
Can be obtained by substituting the above formula
U01＝U3a+Ui (5)
According to the principle of virtual interruption, there are
According to the formula, when the constant current preset resistor RS is constant, the output current and the input signal have a certain linear relation and are irrelevant to other load impedance values; if the input signal Ui is constant, the current I is output0Constant;
in addition, since the operational amplifier U3 is a voltage follower connection, there are
Vref＝Ui (7)
When substituted into formula (6), then have
I.e. the reference signal input terminal Vref is timed, the current I is output0Is constant.
Therefore, the current I is output by the preset DC constant current source of the embodiment0The device can be distinguished according to whether an external mechanical switch or an electrical appliance of an equivalent mechanical switch is switched on or off, and two current circulation conditions are provided:
first electricityUnder the condition of current circulation, when the mechanical switch or the electrical appliance of the equivalent mechanical switch is closed, the AC/DC constant current source outputs current I0There are two current loops, which are current loop I1And a current loop I2The current loop is a constant current source GND composed of an AC/DC constant current source and a resistor R5; while the current loop I2The AC/DC constant current source, the mechanical switch or the electrical appliance of the equivalent mechanical switch and the adjustable resistor RT are connected to the constant current power supply GND, voltage drop can be generated on the adjustable resistor RT, the proper high-level voltage amplitude can be adjusted by adjusting the impedance of the adjustable resistor RT, and the closed working state of the mechanical switch or the electrical appliance of the equivalent mechanical switch can be represented;
in the second current flow condition, when the mechanical switch or the electrical appliance of the equivalent mechanical switch is disconnected, the AC/DC constant current source outputs current I0Only one current loop, namely the current loop I is only the current loop GND which is formed by the AC/DC constant current source and the resistor R5 compared with the first current flowing condition1The loop is set to prevent the AC/DC constant current source from being opened and protected, and the current loop I is used2And a current path is not formed, the voltage drop on the adjustable resistor RT is zero, and the working state of the mechanical switch or an electric appliance equivalent to the mechanical switch in disconnection can be represented.
Fig. 5 is a schematic diagram of a voltage-dropping module, in which a first-stage voltage-dropping module and a voltage-dropping module signal input terminal Vref-in are sequentially connected before the reference signal input terminal Vref, so as to decrease the voltage amplitude of the reference signal.
Referring to fig. 6, an embodiment of the voltage-reducing module is a three-terminal adjustable resistor, one fixed terminal of which is connected to the signal input terminal Vref-in of the voltage-reducing module, the other fixed terminal of which is connected to the ac/dc constant current source GND, and the adjustable terminal of which is connected to the reference signal input terminal Vref.
As shown in fig. 7, when the dc signal is matched to the reference signal input terminal Vref, the output waveform of the output terminal Switch _ out is shown, and it can be seen that when the matched dc reference signal is added to the reference signal input terminal Vref, the on/off of the Switch is characterized by the high/low level variation.
As shown in fig. 8, it can be seen that, when the matching ac reference signal is added to the reference signal input terminal Vref, the on/off of the Switch is represented by the presence of the ac waveform.
Claims (7)
1. A long-range alternating current-direct current Switch signal matcher, is suitable for matching the direct current or alternating current reference signal to characterize the switching on-off long-range converting circuit, wherein including input end Switch _ in, output end Switch _ out, reference signal input end Vref and alternating current-direct current Switch signal match module; the input end Switch _ in is provided with a pair of wiring terminals and is mainly used for connecting a mechanical Switch or an electrical appliance with an equivalent mechanical Switch; the output end Switch _ out is connected with an indicator or a controller which is used for receiving a matched direct current or alternating current reference signal to represent the on-off of the Switch; the reference signal input end Vref is used for matching a direct current or alternating current reference signal, and when the on-off of a switch needs to be represented by high and low level changes, the direct current reference signal is matched; when the on-off of the switch needs to be represented by the on-off of an alternating current waveform, an alternating current reference signal is matched; the alternating current-direct current Switch signal matching module is used for receiving the signals of the input end Switch _ in and the reference signal input end Vref, converting the signals into corresponding signals after circuit conversion, and sending the signals to the output end Switch _ out; the alternating current-direct current Switch signal matching module comprises an alternating current-direct current constant current source, a dummy load and an adjusting resistor, wherein the input end of the alternating current-direct current constant current source is connected with the reference signal input end Vref, the output end of the alternating current-direct current constant current source is respectively connected with one end of the input end Switch _ in and one end of the dummy load, the other end of the dummy load is respectively connected with the alternating current-direct current constant current source GND, one end of the adjusting resistor and one end of the output end Switch _ out, the other end of the input end Switch _ in is respectively connected with the other end of the adjusting resistor and the other end of the output end Switch _ out, and the adjusting resistor is used.
2. The remote ac/dc switching signal matcher according to claim 1, wherein the dummy load is a fixed resistor or an adjustable resistor, and is an electronic load with an equivalent fixed resistor or an equivalent adjustable resistor function.
3. The remote ac/dc switching signal matcher according to claim 1, wherein the adjusting resistor is a fixed resistor or an adjustable resistor, and is an electronic load with an equivalent fixed resistor or an equivalent adjustable resistor function.
4. The apparatus according to claim 1, wherein the ac/dc constant current source is a circuit composed of operational amplifiers.
5. The remote ac/dc switching signal matcher according to claims 1 to 4, wherein the ac/dc constant current source comprises an operational amplifier U1, an operational amplifier U2, an operational amplifier U3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a constant current preset resistor RS and an adjustable resistor RT; the resistor R5 is the dummy load, and the adjustable resistor RT is the adjusting resistor; the non-inverting input terminal U1a of the operational amplifier U1 is connected with the reference signal input terminal Vref, the inverting input terminal U1b of the operational amplifier U1 is respectively connected with the output terminal of the operational amplifier U1 and one end of the resistor R3, and the other end of the resistor R3 is respectively connected with one end of the resistor R4 and the non-inverting input terminal U2a of the operational amplifier U2; the inverting input end U2b of the operational amplifier U2 is respectively connected with one end of a resistor R1 and one end of a resistor R2, and the other end of the resistor R1 is connected with an alternating current-direct current constant current source GND; the other end of the resistor R2 is respectively connected with the output end of the operational amplifier U2 and one end of the constant current preset resistor RS; the other end of the constant current preset resistor RS is respectively connected with one end of a resistor R5, one end of the input end Switch _ in and the non-inverting input end U3a of the operational amplifier U3, and the inverting input end U3b of the operational amplifier U3 is respectively connected with the output end of the operational amplifier U3 and the other end of the resistor R4; the other end of the input end Switch _ in is respectively connected with one end of an adjustable resistor RT and one end of the output end Switch _ out; the other end of the output end Switch _ out is connected with the other end of the adjustable resistor RT, the other end of the resistor R5 and the alternating current-direct current constant current source GND respectively.
6. The remote ac/dc switching signal matcher of claim 1, wherein a primary voltage reduction module and a voltage reduction module signal input terminal Vref-in are sequentially connected before the reference signal input terminal Vref, for reducing the voltage amplitude of the reference signal.
7. The remote ac/dc switching signal matcher according to claim 6, wherein the voltage reducing module is a three-terminal adjustable resistor, one fixed terminal of the three-terminal adjustable resistor is connected to the signal input terminal Vref-in of the voltage reducing module, the other fixed terminal of the three-terminal adjustable resistor is connected to the ac/dc constant current source GND, and the adjustable terminal of the three-terminal adjustable resistor is connected to the reference signal input terminal Vref.
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