Pulse signal output circuit of encoder
By designing an encoder pulse signal output circuit, using interface switches and multiple chip combinations, free switching between RS232 and CAN bus interfaces is achieved, which solves the problem that existing encoder manufacturers need to stock two circuit boards, achieving the effect of easy use, low cost and reduced maintenance costs.
Patent Information
- Application Number
- CN202421831404.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-31
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2034-07-31
AI Technical Summary
Existing encoder manufacturers need to stock two different types of circuit boards to adapt to the differences between the RS232 serial communication interface and the CAN bus communication interface, resulting in inconvenient production management, high costs and high maintenance costs.
Design an encoder pulse signal output circuit, through the combination of the encoder chip, interface switch, switching chip, CAN transceiver chip and RS232 level conversion chip, the interface switch output level is controlled, the output channel of the encoder chip is switched, and the free switching between the RS232 and CAN bus interfaces is realized.
The encoder chip control switching of the switching chip output channel is realized. It can not only output digital pulse signals through serial communication, but also output digital pulse signals through CAN bus communication, which is easy to use, low cost, reduce maintenance costs, convenient replacement, and simple production management.
Smart Images
Figure CN222926971U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of encoders, and particularly to an encoder pulse signal output circuit. Background Art
[0002] The fuel dispenser encoder is the core component of the fuel dispenser system. When the start key of the fuel dispenser is activated, the motor of the system is started, gasoline enters the flow measurement converter and drives the encoder to rotate, thereby converting the corresponding angular displacement signal into a pulse signal and transmitting it to the metering microprocessor on the main board of the fuel dispenser. Currently, the domestic encoder pulse signal output methods can generally be divided into two types according to the different interface methods of the fuel dispenser main board. One is to output digital pulses through the RS232 serial communication interface, and the other is to output digital pulses through the CAN bus communication interface. The two pulse output methods have different interfaces, and the circuit designs adopted are completely different. Existing encoder manufacturers need to stock two different types of circuit boards to adapt to the two different output methods, which brings inconvenience to production management and also increases the production cost and maintenance cost. Summary of the Invention
[0003] In view of this, this application proposes an encoder pulse signal output circuit.
[0004] According to one aspect of this application, there is provided an encoder pulse signal output circuit, which is characterized in that it is used to transmit pulse signals to the metering microprocessor on the main board of the fuel dispenser, and includes: an encoder chip, an interface switch, a switch chip, a CAN transceiver chip, and an RS232 level conversion chip;
[0005] The interface switch is electrically connected to the encoder chip. When the interface switch is in a high-level state, the first output terminal of the encoder chip outputs an address strobe signal A. When the interface switch is in a low-level state, the second output terminal of the encoder chip outputs an address strobe signal B.
[0006] The first output terminal of the encoder chip is electrically connected to the first input terminal of the switch chip for transmitting the address strobe signal A; the second output terminal of the encoder chip is electrically connected to the second input terminal of the switch chip for transmitting the address strobe signal B;
[0007] The third output terminal of the encoder chip is electrically connected to the third input terminal of the switch chip through the CAN transceiver chip for outputting a pulse signal A to the third input terminal of the switch chip through the CAN bus communication, so that when switching to the third input terminal of the switch chip to work, the output terminal of the switch chip outputs the pulse signal A;
[0008] The fourth output terminal of the encoder chip is electrically connected to the fourth input terminal of the switch chip through an RS232 level conversion chip, which is suitable for outputting the pulse signal B to the fourth input terminal of the switch chip through serial communication; so that when switching to the fourth input terminal of the switch chip for operation, the output terminal of the switch chip outputs the pulse signal B.
[0009] The output terminal of the switch chip is suitable for being electrically connected to the metering microprocessor of the fuel dispenser main board to output the pulse signal A or the pulse signal B.
[0010] In a possible implementation manner, the model of the switch chip is 74HC4052D.
[0011] In a possible implementation manner, the model of the RS232 level conversion chip is MAX3232.
[0012] In a possible implementation manner, it further includes: a connector, and the output terminal of the switch chip is electrically connected to the metering microprocessor of the fuel dispenser main board through the connector.
[0013] In a possible implementation manner, the CAN transceiver chip is provided with a resistor;
[0014] The RS terminal of the CAN transceiver chip is grounded through the resistor.
[0015] In a possible implementation manner, the RS232 level conversion chip is provided with a filter capacitor;
[0016] The voltage input terminal of the RS232 level conversion chip accesses the voltage through the filter capacitor.
[0017] In a possible implementation manner, the RS232 level conversion chip is provided with a first coupling capacitor;
[0018] One pole of the first coupling capacitor is electrically connected to the C1+ terminal of the RS232 level conversion chip, and the other pole of the first coupling capacitor is electrically connected to the C1- terminal of the RS232 level conversion chip.
[0019] In a possible implementation manner, the RS232 level conversion chip is provided with a second coupling capacitor;
[0020] One pole of the second coupling capacitor is electrically connected to the C2+ terminal of the RS232 level conversion chip, and the other pole of the second coupling capacitor is electrically connected to the C2- terminal of the RS232 level conversion chip.
[0021] Beneficial effects: This application integrates two output forms, namely the RS232 serial communication interface and the CAN bus communication interface, on the same main board. By controlling the output level of the interface switch S1, the encoder chip can control and switch the output channels of the switch chip, thus realizing the free switching between the two interfaces. It can either communicate with the fuel dispenser main board through the serial port to output the digital pulse signal B, or output the digital pulse signal A through the CAN bus communication. It has the advantages of convenient use, low cost, reduced maintenance cost, easy replacement, and simple production management, effectively solving the production and after-sales problems.
[0022] Other features and aspects of the present application will become clear from the following detailed description of the exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The drawings included in and constituting a part of the specification, together with the specification, illustrate the exemplary embodiments, features, and aspects of the present application and are used to explain the principles of the present application.
[0024] Figure 1 The circuit diagram of the switch chip showing an embodiment of the present application;
[0025] Figure 2 The circuit diagram of the interface switch showing an embodiment of the present application;
[0026] Figure 3 The circuit diagram of the CAN transceiver chip showing an embodiment of the present application;
[0027] Figure 4 The circuit diagram of the RS232 level conversion chip showing an embodiment of the present application;
[0028] Figure 5 The circuit diagram of the encoder chip showing an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] The following will detail various exemplary embodiments, features, and aspects of the present application with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.
[0030] Among them, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention or simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.
[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.
[0032] The special term "exemplary" herein means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" herein need not be construed as superior to or better than other embodiments.
[0033] In addition, for better illustration of the present application, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present application can be implemented without some specific details. In some instances, methods, means, elements, and circuits well-known to those skilled in the art are not described in detail so as to highlight the gist of the present application.
[0034] Figure 1 The circuit diagram of the switch chip U4 showing the embodiment of the present application; Figure 2 The circuit diagram of the interface switch S1 showing the embodiment of the present application; Figure 3 The circuit diagram of the CAN transceiver chip U2 showing the embodiment of the present application; Figure 4 The circuit diagram of the RS232 level conversion chip U3 showing the embodiment of the present application; Figure 5 The circuit diagram of the encoder chip U1 showing the embodiment of the present application. As Figures 1-5As shown, a kind of encoder pulse signal output circuit includes: an encoder chip U1, an interface switch S1, a switch chip U4, a CAN transceiver chip U2, and an RS232 level conversion chip U3; the interface switch S1 is electrically connected to the encoder chip U1. When the interface switch S1 is in the high-level state, the first output terminal of the encoder chip U1 outputs an address strobe signal A. When the interface switch S1 is in the low-level state, the second output terminal of the encoder chip U1 outputs an address strobe signal B; the first output terminal of the encoder chip U1 is electrically connected to the first input terminal of the switch chip U4 for transmitting the address strobe signal A; the second output terminal of the encoder chip U1 is electrically connected to the second input terminal of the switch chip U4 for transmitting the output address strobe signal B; the third output terminal of the encoder chip U1 is electrically connected to the third input terminal of the switch chip U4 through the CAN transceiver chip U2, and is suitable for outputting a pulse signal A to the third input terminal of the switch chip U4 through CAN bus communication, so that when switching to the third input terminal of the switch chip U4 to work, the output terminal of the switch chip U4 outputs the pulse signal A; the fourth output terminal of the encoder chip U1 is electrically connected to the fourth input terminal of the switch chip U4 through the RS232 level conversion chip U3, and is suitable for outputting a pulse signal B to the fourth input terminal of the switch chip U4 through serial communication, so that when switching to the fourth input terminal of the switch chip U4 to work, the output terminal of the switch chip U4 outputs the pulse signal B; the output terminal of the switch chip U4 is suitable for being electrically connected to the metering microprocessor of the fuel dispenser main board to output the pulse signal A or the pulse signal B.
[0035] Here, it should be noted that the encoder chip U1 is suitable for outputting digital pulse signals to the CAN transceiver chip U2 and the RS232 level conversion chip U3; the CAN transceiver chip U2 is suitable for sending the pulse signal A to the third input terminal of the switch chip U4, and the RS232 level conversion chip U3 is suitable for sending the pulse signal B to the fourth input terminal of the switch chip U4; the interface switch S1 is electrically connected to the encoder chip U1. According to different high and low level states of the selected interface switch S1, the encoder chip U1 can output different A\B address selection signals. When the interface switch S1 is in the high level state, the encoder chip U1 outputs the address selection signal A to the switch chip U4; when the interface switch S1 is in the low level state, the encoder chip U1 outputs the address selection signal B to the switch chip U4; the switch chip U4 can select two different data channels according to different address selection signals (i.e., the data channel between the third input terminal and the output terminal of the switch chip U4, the data channel between the fourth input terminal and the output terminal of the switch chip U4). Further, when the switch chip U4 receives the address selection signal A, the third input terminal and the output terminal of the switch chip U4 are connected. At this time, the output terminal of the switch chip U4 outputs the pulse signal A (bus data signal) of the CAN transceiver chip U2 and sends it to the metering microprocessor of the fuel dispenser main board; when the switch chip U4 receives the address selection signal B, the fourth input terminal and the output terminal of the switch chip U4 are connected. At this time, the output terminal of the switch chip U4 outputs the pulse signal B (serial data signal) of the RS232 level conversion chip U3 and sends it to the metering microprocessor of the fuel dispenser main board. In actual use, only according to the interface characteristics of the metering microprocessor at the main board end, by switching the high and low levels of the interface switch S1, one of the two data channels can be freely selected to realize the data communication between the encoder chip U1 and the metering microprocessor. This application integrates two output forms, namely the RS232 serial communication interface and the CAN bus communication interface, on the same main board. By controlling the output level of the interface switch S1, the control switch of the output channel of the encoder chip U1 to the switch chip U4 can be realized, and thus the free switching of the two interfaces can be achieved. It can either communicate with the fuel dispenser main board through the serial port to output the digital pulse signal B, or output the digital pulse signal A through the CAN bus communication, with the advantages of convenient use, low cost, reduced maintenance cost, convenient replacement, simple production management, etc., effectively solving the production and after-sales problems.
[0036] In a possible implementation, the first pin of the interface switch S1 is grounded, the third pin of the interface switch S1 is connected to a voltage, the second pin of the interface switch S1 is electrically connected to the first pin (PB.14 terminal) of the encoder chip U1. When the second pin of the interface switch S1 is connected to the third pin of the interface switch S1, the interface switch S1 is in a high level state. When the first pin of the interface switch S1 is connected to the third pin of the interface switch S1, the interface switch S1 is in a low level state. Further, the interface switch S1 can be a DIP switch or a push-button switch.
[0037] In a possible implementation, the model of the switch chip U4 is 74HC4052D.
[0038] Further, the first output terminal of the encoder chip U1 is the eighth pin (PA.9 terminal) of the encoder chip U1, and the first input terminal of the switch chip U4 is the thirteenth pin (1Z terminal) of the switch chip U4; the first output terminal of the encoder chip U1 is electrically connected to the first input terminal of the switch chip U4 to transmit the address strobe signal A, that is, the eighth pin (PA.9 terminal) of the encoder chip U1 is electrically connected to the thirteenth pin (1Z terminal) of the switch chip U4 to transmit the address strobe signal A.
[0039] Further, the second output terminal of the encoder chip U1 is the ninth pin (PA.8 terminal) of the encoder chip U1, and the second input terminal of the switch chip U4 is the third pin (2Z terminal) of the switch chip U4; the second output terminal of the encoder chip U1 is electrically connected to the second input terminal of the switch chip U4 to transmit the address strobe signal B, that is, the ninth pin (PA.8 terminal) of the encoder chip U1 is electrically connected to the third pin (2Z terminal) of the switch chip U4 to transmit the address strobe signal B.
[0040] In a possible implementation, the third output terminal of the encoder chip U1 is electrically connected to the CAN transceiver chip U2 to transmit digital pulse signals to the CAN transceiver chip U2. Further, the third output terminal of the encoder chip U1 is the sixth pin (PA.11 terminal) and the seventh pin (PA.10 terminal) of the encoder chip U1. The sixth pin (PA.11 terminal) of the encoder chip U1 is electrically connected to the fourth pin (RXD terminal) of the CAN transceiver chip U2, and the seventh pin (PA.10 terminal) of the encoder chip U1 is electrically connected to the first pin (TXD terminal) of the CAN transceiver chip U2.
[0041] In a possible implementation, the CAN transceiver chip U2 is electrically connected to the third input terminal of the switch chip U4 to transmit the pulse signal A to the third input terminal of the switch chip U4. Further, the third input terminal of the switch chip U4 is the 12th pin (1Y0 terminal) and the 1st pin (2Y0 terminal) of the switch chip U4; the 7th pin (CANH terminal) of the CAN transceiver chip U2 is electrically connected to the 12th pin (1Y0 terminal) of the switch chip U4, and the 6th pin (CANL terminal) of the CAN transceiver chip U2 is electrically connected to the 1st pin (2Y0 terminal) of the switch chip U4.
[0042] In a possible implementation, the CAN transceiver chip U2 is provided with a resistor R3; the RS terminal of the CAN transceiver chip U2 is grounded through the resistor R3. Further, the 2nd pin (GND terminal) of the CAN transceiver chip U2 is grounded; the 3rd pin (VCC terminal) of the CAN transceiver chip U2 is connected to the operating voltage; the 8th pin (RS terminal) of the CAN transceiver chip U2 is electrically connected to a resistor R3; it should be noted that connecting the 8th pin (RS terminal) of the CAN transceiver chip U2 in series with a resistor R3 to ground can change the resistor to control the slopes of CANH and CANHL and reduce radiation.
[0043] In a possible implementation, the model of the RS232 level conversion chip U3 is MAX3232.
[0044] The fourth output terminal of the encoder chip U1 is electrically connected to the RS232 level conversion chip U3 to transmit the digital pulse signal to the RS232 level conversion chip U3. Further, the fourth output terminal of the encoder chip U1 is the 47th pin (PA.3 terminal) and the 46th pin (PA.2 terminal) of the encoder chip U1, the 47th pin (PA.3 terminal) of the encoder chip U1 is electrically connected to the 12th pin (R1OUT terminal) of the RS232 level conversion chip U3, and the 46th pin (PA.2 terminal) of the encoder chip U1 is electrically connected to the 11th pin (TIN terminal) of the RS232 level conversion chip U3.
[0045] In a possible implementation, the RS232 level conversion chip U3 is electrically connected to the fourth input terminal of the switch chip U4 to transmit the pulse signal B to the fourth input terminal of the switch chip U4. Further, the fourth input terminal of the switch chip U4 is the 14th pin (1Y1 terminal) and the 5th pin (2Y1 terminal) of the switch chip U4; the 13th pin (RIN terminal) of the RS232 level conversion chip U3 is electrically connected to the 5th pin (2Y1 terminal) of the switch chip U4, and the 14th pin (T1OUT terminal) of the RS232 level conversion chip U3 is electrically connected to the 14th pin (1Y1 terminal) of the switch chip U4.
[0046] In a possible implementation, the RS232 level conversion chip U3 is provided with a filter capacitor C9; the voltage input terminal of the RS232 level conversion chip U3 is connected to the voltage through the filter capacitor C9. As Figure 4 shown, the 16th pin (VCC terminal) of the RS232 level conversion chip U3 is connected to the voltage through the filter capacitor C9. The 15th pin (GND terminal) of the RS232 level conversion chip U3 is grounded.
[0047] In a possible implementation, the RS232 level conversion chip U3 is provided with a first coupling capacitor C6; one pole of the first coupling capacitor C6 is electrically connected to the C1+ terminal of the RS232 level conversion chip U3, and the other pole of the first coupling capacitor C6 is electrically connected to the C1- terminal of the RS232 level conversion chip U3.
[0048] In a possible implementation, the RS232 level conversion chip U3 is provided with a second coupling capacitor C7; one pole of the second coupling capacitor C7 is electrically connected to the C2+ terminal of the RS232 level conversion chip U3, and the other pole of the second coupling capacitor C7 is electrically connected to the C2- terminal of the RS232 level conversion chip U3. It should be noted that the setting of the first coupling capacitor C6 and the second coupling capacitor C7 can prevent noise from affecting the performance of the RS232 level conversion chip U3 itself and prevent transmission noise from affecting the performance of other circuits.
[0049] In summary, the 13th pin and the 3rd pin of the switch chip U4 are electrically connected to the encoder chip U1 to access the address strobe signal A and the address strobe signal B. The 12th pin and the 1st pin of the switch chip U4 access the pulse signal A of the CAN transceiver chip U2. The 14th pin and the 3rd pin of the switch chip U4 access the pulse signal B of the RS232 level conversion chip U3. The 7th pin (VEE terminal) of the switch chip U4 is connected to the operating voltage, and the 8th pin (GND terminal) of the switch chip U4 is grounded.
[0050] It should be noted that the output terminals of the switch chip U4 are the 9th pin (S1 terminal) and the 10th pin (S0 terminal) of the switch chip U4; the 12th pin (1Y0 terminal) of the switch chip U4 is electrically connected to the 10th pin (S0 terminal) of the switch chip U4 in a switchable manner, and the 14th pin (1Y1 terminal) of the switch chip U4 is also electrically connected to the 10th pin (S0 terminal) of the switch chip U4 in a switchable manner; the 1st pin (2Y0 terminal) of the switch chip U4 is electrically connected to the 9th pin (S1 terminal) of the switch chip U4 in a switchable manner, and the 5th pin (2Y1 terminal) of the switch chip U4 is also electrically connected to the 9th pin (S1 terminal) of the switch chip U4 in a switchable manner. Further, it should be noted that when it is necessary to output the pulse signal A of the CAN transceiver chip U2, the interface switch S1 is set to the high level state, the 12th pin (1Y0 terminal) of the switch chip U4 is connected to the 10th pin (S0 terminal) of the switch chip U4, the 14th pin (1Y1 terminal) of the switch chip U4 is disconnected from the 10th pin (S0 terminal) of the switch chip U4, the 1st pin (2Y0 terminal) of the switch chip U4 is connected to the 9th pin (S1 terminal) of the switch chip U4, and the 5th pin (2Y1 terminal) of the switch chip U4 is disconnected from the 9th pin (S1 terminal) of the switch chip U4. On the contrary, when it is necessary to output the pulse signal B of the RS232 level conversion chip U3, the interface switch S1 is set to the low level state, the 12th pin (1Y0 terminal) of the switch chip U4 is disconnected from the 10th pin (S0 terminal) of the switch chip U4, the 14th pin (1Y1 terminal) of the switch chip U4 is connected to the 10th pin (S0 terminal) of the switch chip U4, the 1st pin (2Y0 terminal) of the switch chip U4 is disconnected from the 9th pin (S1 terminal) of the switch chip U4, and the 5th pin (2Y1 terminal) of the switch chip U4 is connected to the 9th pin (S1 terminal) of the switch chip U4.
[0051] In a possible implementation manner, it further includes: a connector J3, and the output terminal of the switch chip U4 is electrically connected to the metering microprocessor of the fuel dispenser main board through the connector J3. That is, both the 9th pin (S1 terminal) and the 10th pin (S0 terminal) of the switch chip U4 are electrically connected to the input terminal of the connector J3, and one of the output terminals of the connector J3 is electrically connected to the metering microprocessor of the fuel dispenser main board. At the same time, the interface switch S1 is electrically connected to the encoder chip U1 through the connector J3. Further, the 2nd pin of the interface switch S1 is electrically connected to the 3rd pin of the connector J3, and the other output terminal of the connector J3 is electrically connected to the 1st pin (PB.14 terminal) of the encoder chip U1.
[0052] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.
Claims
1. An encoder pulse signal output circuit, characterized in that: Used to transmit pulse signals to the metering microprocessor of the fuel dispenser mainboard, including: encoder chip, interface switch, switch chip, CAN transceiver chip and RS232 level conversion chip; The interface switch is electrically connected to the encoder chip, and is adapted to output an address selection signal A at a first output terminal of the encoder chip when the interface switch is in a high level state, and to output an address selection signal B at a second output terminal of the encoder chip when the interface switch is in a low level state. The first output terminal of the encoder chip is electrically connected to the first input terminal of the switch chip, and is suitable for transmitting the address selection signal A; the second output terminal of the encoder chip is electrically connected to the second input terminal of the switch chip, and is suitable for transmitting the address selection signal B; The third output end of the encoder chip is electrically connected to the third input end of the switch chip through the CAN transceiver chip, and is adapted to output a pulse signal A to the third input end of the switch chip through CAN bus communication, so that when the third input end of the switch chip is switched to work, the output end of the switch chip outputs the pulse signal A; The fourth output end of the encoder chip is electrically connected to the fourth input end of the switch chip through the RS232 level conversion chip, and is suitable for outputting a pulse signal B to the fourth input end of the switch chip through serial communication; so that when the fourth input end of the switch chip is switched to work, the output end of the switch chip outputs the pulse signal B; The output end of the switch chip is suitable for being electrically connected to the metering microprocessor of the fuel dispenser mainboard to output the pulse signal A or the pulse signal B.
2. The encoder pulse signal output circuit according to claim 1, characterized in that: The model of the switch chip is 74HC4052D.
3. The encoder pulse signal output circuit according to claim 1, characterized in that: The model of the RS232 level conversion chip is MAX3232.
4. The encoder pulse signal output circuit according to claim 1, characterized in that: Also includes: Connector, the output end of the switch chip is electrically connected to the metering microprocessor of the fuel dispenser mainboard through the connector.
5. The encoder pulse signal output circuit according to claim 1, characterized in that: The CAN transceiver chip is provided with a resistor; The RS terminal of the CAN transceiver chip is grounded through the resistor.
6. The encoder pulse signal output circuit according to claim 3, characterized in that: The RS232 level conversion chip is provided with a filter capacitor; The voltage input terminal of the RS232 level conversion chip is connected to the voltage through the filter capacitor.
7. The encoder pulse signal output circuit according to claim 3, characterized in that: The RS232 level conversion chip is provided with a first coupling capacitor; One electrode of the first coupling capacitor is electrically connected to the C1+ terminal of the RS232 level conversion chip, and the other electrode of the first coupling capacitor is electrically connected to the C1- terminal of the RS232 level conversion chip.
8. The encoder pulse signal output circuit according to claim 7, characterized in that: The RS232 level conversion chip is provided with a second coupling capacitor; One electrode of the second coupling capacitor is electrically connected to the C2+ terminal of the RS232 level conversion chip, and the other electrode of the second coupling capacitor is electrically connected to the C2- terminal of the RS232 level conversion chip.