RS485 communication circuit

Abstract

The utility model relates to an RS485 communication circuit. The circuit comprises a control module, a first interface module, a second interface module, a first logic control element and an IL3585 chip, a first power supply pin is connected with the first interface module, a first power supply and the first logic control element, and a second power supply pin is connected with the control module and a second power supply. The control module is connected with the first interface module and the first power supply, the bus output pin is connected with the first interface module, the read data enabling pin is connected with the control module, the enabling pin and the bus input pin are both connected with the first logic control element, and the first logic control element is connected with the first interface module. The first interface module is connected with a first power supply, the differential signal transceiving pin is connected with the second interface module, and the second interface module is connected with the second power supply pin. Compared with the prior art, the circuit has the advantages that the circuit failure rate is reduced on the premise that the equipment complexity is not increased, and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of communication circuits, and in particular to an RS485 communication circuit. Background Art

[0002] In the existing RS485 communication module, ADM1485 is usually used for transceiver signal processing and PC410L optocoupler signal isolation. However, due to unreasonable circuit design, the optocoupler works at the edge of the rated current and generates a large amount of heat. The heat resistance temperature range of ADM1485 is 0°C to +70°C. In a strong electromagnetic interference environment, the service life of the components is shortened and they are prone to premature damage, resulting in the burnout of the isolation optocoupler PC410L and the RS485 transceiver chip ADM1485JR, and further resulting in a high failure rate of the RS485 communication module. Therefore, how to reduce the failure rate without increasing the complexity of the equipment has become a problem to be solved in this field. Summary of the Utility Model

[0003] The purpose of the utility model is to provide an RS485 communication circuit to overcome the defect of the high failure rate of the existing RS485 communication module.

[0004] The purpose of the utility model can be realized by the following technical solutions:

[0005] The utility model provides an RS485 communication circuit. A first power supply and a second power supply supply power to the circuit. The circuit includes a control module, a first interface module, a second interface module, and a signal processing module. The signal processing module includes a first logic control element and an IL3585 chip. The IL3585 chip includes a first power supply pin, a second power supply pin, a bus output pin, a read data enable pin, an enable pin, a bus input pin, differential signal transceiver pins, and four ground pins. The first power supply pin is connected to the first interface module, the first power supply, and the first logic control element. The second power supply pin is connected to the control module and is also connected to the second power supply. The control module is connected to the first interface module and the first power supply. The bus output pin is connected to the first interface module. The read data enable pin is connected to the control module. The enable pin and the bus input pin are both connected to the first logic control element. The first logic control element is connected to the first interface module. The first interface module is connected to the first power supply. The differential signal transceiver pins are connected to the second interface module. The second interface module is connected to the second power supply pin. The four ground pins are connected inside the IL3585 chip and are all grounded. The ground pins of the control module, the first interface module, and the second interface module are all grounded.

[0006] As a preferred technical solution, the first power pin is connected to the power pin of the first logic control element, and is grounded through a first capacitor and a second capacitor at the same time. The first capacitor and the second capacitor are connected in parallel.

[0007] As a preferred technical solution, the signal processing module further includes a third capacitor, a fourth capacitor and a fifth capacitor connected in parallel. One end of the parallel connection is connected to the second power supply, and the other end is grounded.

[0008] As a preferred technical solution, one end connected to the second power supply is further connected to a first resistor, a second resistor and a first voltage stabilizing diode. The first resistor and the second resistor are connected in parallel and then connected in series with the first voltage stabilizing diode. The other end of the first voltage stabilizing diode is connected to the second interface module.

[0009] As a preferred technical solution, the control module includes a second logic control element, a first power control element and a second power control element. The second logic control element is connected to the first interface module, the first power supply, the read data enable pin and the first power control element. The first power control element is connected to the second power control element, and the second power control element is connected to the second power pin.

[0010] As a preferred technical solution, the control module further includes a sixth capacitor and a seventh capacitor connected in parallel. One end of the parallel connection is connected to the first power control element, and the other end is grounded.

[0011] As a preferred technical solution, the control module further includes an eighth capacitor and a ninth capacitor connected in parallel. One end of the parallel connection is connected to the first power control element, the second logic control element, the first interface module and the first power supply, and the other end is grounded.

[0012] As a preferred technical solution, the second interface module further includes a second voltage stabilizing diode and an inductor. One end of the second voltage stabilizing diode is connected to the differential signal transceiver pin, and the other end is grounded. One end of the inductor is connected to the ground pin of the second interface module, and the other end is grounded.

[0013] As a preferred technical solution, the second voltage stabilizing diode includes a transient suppression diode.

[0014] As a preferred technical solution, both the first interface module and the second interface module adopt a double-row female with a pitch of 2.54 mm.

[0015] Compared with the prior art, the present utility model has the following beneficial effects:

[0016] 1. The present utility model selects the IL3585 digital isolation chip to replace the traditional isolation optocoupler PC410L and transceiver chip ADM1485JR. Using the IL3585 digital isolation chip as the transceiver of the RS485 communication module, integrating the digital isolation and transceiver functions in one chip. On the one hand, the integration degree is higher, which can simplify the circuit design and PCB layout. And the IL3585 digital isolation chip internally integrates a thermal pipe break protection function, automatically shutting down the circuit when the temperature is too high to prevent damage. On the other hand, it has higher voltage resistance and faster speed, improving the reliability of the RS485 circuit, reducing the failure rate of the RS485 circuit, enhancing the tolerance of components in a strong electromagnetic interference environment, and helping to extend the service life of components;

[0017] 2. The present utility model adopts multiple power control components and interface modules, which can not only meet the complex working requirements during circuit operation but also improve the expandability of the entire circuit;

[0018] 3. The present utility model uses multiple components such as capacitors, resistors, inductors, and voltage regulators to decouple and filter the circuit, further improving the stability and reliability of the RS485 communication circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the RS485 communication circuit provided by the embodiment of the present utility model;

[0020] Figure 2 is a schematic diagram of the circuit structure of the signal processing module in the embodiment of the present utility model;

[0021] Figure 3 is a schematic diagram of the circuit structure of the control module in the embodiment of the present utility model;

[0022] Figure 4 is a schematic diagram of the circuit structure of the first interface module in the embodiment of the present utility model;

[0023] Figure 5 is a schematic diagram of the circuit structure of the second interface module in the embodiment of the present utility model;

[0024] Figure 6 is a schematic diagram of the partial circuit structure of the control module, the first interface module, and the signal processing module in the embodiment of the present utility model;

[0025] Figure 7 is a schematic diagram of the partial circuit structure of the control module and the signal processing module in the embodiment of the present utility model;

[0026] Among them: 1. Control module; 2. First interface module; 3. Second interface module; 4. Signal processing module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0028] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use. It is only for the convenience of describing the present utility model and 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 utility model. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood 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 this application, "a plurality" means two or more, unless otherwise specifically defined.

[0030] Embodiment:

[0031] As Figure 1 shown, this embodiment provides an RS485 communication circuit, which is powered by a first power supply VDD1 and a second power supply VDD2. The circuit includes a control module 1, a first interface module 2, a second interface module 3, and a signal processing module 4.

[0032] As Figure 2 shown, the signal processing module 4 includes a first logic control element and an IL3585 chip U1. The first logic control element uses an integrated flip-flop U2, with the model number SN74AHCT14PWR; as Figure 3 shown, the control module 1 includes a second logic control element, a first power control element, and a second power control element. The second logic control element uses a logic gate element U4 with the model number 74AHCT1G32GW. The first power control element uses a DC-DC converter U5 with the model number NTE0505MC. The second power control element uses a voltage regulator U6 with the model number KF50BD-TR; as Figure 4 and Figure 5As shown, the first interface module 2 includes a 2.54 - 2*7P vertical - mounted female H1, and the second interface module 3 includes a 2.54 - 2*5P vertical - mounted female H2.

[0033] Combined with Figure 6 and Figure 7 As shown, in the signal processing module 4, the IL3585 chip U1 specifically includes: a first power supply pin (pin 1, symbol VDD1), a second power supply pin (pin 16, symbol VDD2), a bus output pin (pin 3, symbol R), a read data enable pin (pin 4, symbol nRE), an enable pin (pin 5, symbol DE), a bus input pin (pin 6, symbol D), differential signal transceiver pins (pins 12 and 13, symbols A and B), and four ground pins (pins 2, 15, 8, 9, symbols GND1 and GND2). In addition, the IL3585 chip U1 also includes pins 7, 10, 11, and 14.

[0034] The first power supply pin is connected to the power supply pin VCC of the flip - flop U2, and at the same time is grounded through a first capacitor C1 (50V, 100nF) and a second capacitor C2 (50V, 100nF). The first capacitor C1 and the second capacitor C2 are connected in parallel. At the same time, the first power supply pin is also connected to the first power supply VDD1, and is also connected to one end of a resistor R2 with a resistance value of 47kΩ. The other end of the resistor R2 is simultaneously connected to pin 1A of the flip - flop U2 and pin 11 of the vertical - mounted female H1. The bus output pin is connected to pin 12 of the vertical - mounted female H1. The read data enable pin is connected to pin Y of the logic gate element U4 through a 0Ω resistor R5. The enable pin is connected to pin 1Y of the flip - flop U2 through a 0Ω resistor R6. The bus input pin is connected to pin 4Y of the flip - flop U2.

[0035] The second power supply pin is connected to the first pin (VOUT) of the voltage regulator U6, and is also connected to the second power supply VDD2. A third capacitor C3 (50V, 100nF), a fourth capacitor C6 (50V, 100nF), and a fifth capacitor C7 (50V, 15μF) are connected in parallel. One end of the parallel connection is connected to the second power supply pin and the second power supply VDD2, and the other end is grounded. The end connected to the second power supply VDD2 is also connected to a first resistor R9 (100Ω), a second resistor R10 (100Ω), and a first zener diode D1 (SS16 - E3 / 61T). R9 and R10 are connected in parallel and then connected in series with the first zener diode D1. The other end of the first zener diode D1 is connected to pin 10 of the vertical - mounted female H2.

[0036] One end of pin A is connected in series with resistor R8 (4.7 Ω), and the other end of resistor R8 is connected to the 5th and 7th pins of the vertical mount female H2. At the same time, a resistor R11 is connected in series at this other end. The other end of resistor R11 (120 Ω) is connected to the 8th pin of the vertical mount female H2. One end of pin B is connected in series with resistor R7 (4.7 Ω), and the other end of resistor R7 is connected to the 4th and 6th pins of the vertical mount female H2.

[0037] In addition, the second interface module 3 also includes two second voltage-regulating diodes D2 (using transient suppression diodes of model SM712) and an inductor L1 (4.7 μH). There is also a node between R8 and R11 that is connected to one end of one of the second voltage-regulating diodes D2. There is also a node between R7 and the pins of the vertical mount female H2 that is connected to one end of the other second voltage-regulating diode D2. The other ends of the two second voltage-regulating diodes D2 are both connected to one end of the inductor L1, and at the same time, this connection point is also grounded. The other end of the inductor L1 is connected to the ground pin of the vertical mount female H2.

[0038] The four ground pins of the IL3585 chip are connected internally in the IL3585 chip and are all grounded. The ground pins of the control module 1, the first interface module 2, and the second interface module 3 are all grounded.

[0039] In the signal processing module 4, a flip-flop U2 is also included. Pin 1A of the flip-flop U2 is directly connected to the 11th pin of the vertical mount male H1; pin 2A is connected to the 10th pin of the vertical mount male H1, and there is a node on the connection line that is connected to pin 6A of the flip-flop U2; pin 3A is connected to one end of a resistor R3 (470 kΩ), and the other end of resistor R3 is connected to the 6th pin of the vertical mount male H1 and is grounded at the same time; the ground pin is connected to the 2nd pin of the vertical mount male H1 through a resistor R1 (0 Ω) and is grounded at the same time; pin 4Y is directly connected to the bus input pin of the IL3585 chip U1; pins 4A, 5A, and 6Y are connected to each other; pin 5Y is connected to the 1st pin of the vertical mount male H1 through a resistor R4 (0 Ω); the 14th pin (power supply pin VCC) of the flip-flop U2 is connected to the first power supply pin of the IL3585 chip U1.

[0040] The 5th pin of the vertical mount male H1 is connected to the first power supply VDD1 and is also connected to the 5th pin of the logic gate element U4; the 8th pin of the vertical mount male H1 is connected to the 1st and 2nd pins of the logic gate element U4; the 12th pin of the vertical mount male H1 is directly connected to the bus output pin.

[0041] In the control module 1, it also includes a sixth capacitor C4 (50V, 100nF) and a seventh capacitor C5 (50V, 4.7nF) connected in parallel. One end of the parallel connection is connected to the 8th pin (+VOUT) of the DC-DC converter U5, and the other end of the parallel connection is grounded and connected to the 7th pin (-VOUT) of the DC-DC converter U5. The 8th pin of the DC-DC converter U5 is connected to the 8th pin (VIN) of the voltage regulator U6 after passing through one end of the parallel connection. The 2nd, 3rd, 6th, and 7th pins of the voltage regulator U6 are all grounded, and the 1st pin is connected to the second power supply pin of the IL3585 chip U1 and the second power supply VDD2.

[0042] The control module 1 also includes an eighth capacitor C8 (50V, 100nF) and a ninth capacitor C9 (50V, 4.7nF) connected in parallel. One end of the parallel connection is simultaneously connected to the 3rd pin (+VIN) of the DC-DC converter U5, the 5th pin (VCC) of the logic gate element U4, and the 5th pin of the vertical mount female H1, and is connected to the first power supply VDD1. The other end of the parallel connection is grounded and is simultaneously connected to the 3rd pin (GND pin) of the logic gate element U4 and the 1st pin (-VIN) of the DC-DC converter U5.

[0043] In addition, the 5th pin of the logic gate element U4 is connected to the 5th pin of the vertical mount female H1 and the first power supply VDD1. The 4th pin of the logic gate element U4 is connected to the read data enable pin of the IL3585 chip U1 through R5. The 3rd pin of the logic gate element U4 is also connected to the 1st pin of the DC-DC converter U5.

[0044] In the second interface module 3, the 10th pin of the vertical mount female H2 is connected to the second power supply pin VDD2 through a series connection of a first zener diode D1, and a parallel connection of R9 and R10 in sequence. The 9th pin is connected to the 2nd pin. The 8th pin is serially connected to pin A of the IL3585 chip U1 through R11 and R8 in sequence. The 5th and 7th pins are both connected to the connection line between R11 and R8. The 4th and 6th pins are both connected to pin B of the IL3585 chip U1 through R7. The 1st pin is grounded after being serially connected with an inductor L1.

[0045] In the traditional design, the RS485 module is designed as an independent PCB board plugged into the main board. Therefore, the aforementioned RS485 communication circuit module based on the IL3585 chip can, without changing the structure of other parts of the main board, use a redesigned improved RS485 module plugged into the main board to replace the original PCB board, without increasing the complexity of the device. At the same time, compared with the designs of ADM1485 and PC410L, the RS485 communication circuit board using the IL3585 chip has a higher integration level. In addition, the IL3585 chip itself is superior to ADM1485 in terms of performance in many aspects such as data transmission rate and supported nodes, and the performance comparison is shown in Table 1.

[0046] Table 1 Performance Parameter Comparison between ADM1485 and IL3585

[0047]

[0048]

[0049] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. An RS485 communication circuit, wherein a first power supply and a second power supply are used to power the circuit, characterized in that: The circuit includes a control module, a first interface module, a second interface module and a signal processing module, the signal processing module includes a first logic control element and an IL3585 chip, the IL3585 chip includes a first power pin, a second power pin, a bus output pin, a read data enable pin, an enable pin, a bus input pin, a differential signal transceiver pin and four ground pins; The first power pin is connected to the first interface module, the first power supply and the first logic control element, the second power pin is connected to the control module and is also connected to the second power supply, the control module is connected to the first interface module and the first power supply, the bus output pin is connected to the first interface module, the read data enable pin is connected to the control module, the enable pin and the bus input pin are both connected to the first logic control element, the first logic control element is connected to the first interface module, the first interface module is connected to the first power supply, the differential signal transceiver pin is connected to the second interface module, the second interface module is connected to the second power pin, the four ground pins are connected inside the IL3585 chip and are all grounded, and the ground pins of the control module, the first interface module and the second interface module are all grounded.

2. The RS485 communication circuit according to claim 1, characterized in that: The first power pin is connected to the power pin of the first logic control element and is grounded through a first capacitor and a second capacitor. The first capacitor and the second capacitor are connected in parallel.

3. The RS485 communication circuit according to claim 1, characterized in that: The signal processing module further includes a third capacitor, a fourth capacitor and a fifth capacitor connected in parallel, one end of the parallel connection is connected to the second power supply, and the other end is grounded.

4. The RS485 communication circuit according to claim 3, characterized in that: One end connected to the second power supply is also connected to a first resistor, a second resistor and a first Zener diode. The first resistor and the second resistor are connected in parallel and then connected in series with the first Zener diode. The other end of the first Zener diode is connected to the second interface module.

5. The RS485 communication circuit according to claim 1, characterized in that: The control module includes a second logic control element, a first power control element and a second power control element, the second logic control element is connected to the first interface module, the first power supply, the read data enable pin and the first power control element, the first power control element is connected to the second power control element, and the second power control element is connected to the second power pin.

6. The RS485 communication circuit according to claim 5, characterized in that: The control module further includes a sixth capacitor and a seventh capacitor connected in parallel, one end of the parallel connection is connected to the first power control element, and the other end is grounded.

7. The RS485 communication circuit according to claim 5, characterized in that: The control module also includes an eighth capacitor and a ninth capacitor connected in parallel, one end of which is connected to the first power control element, the second logic control element, the first interface module and the first power supply, and the other end is grounded.

8. The RS485 communication circuit according to claim 1, characterized in that: The second interface module also includes a second zener diode and an inductor, one end of the second zener diode is connected to the differential signal transceiver pin, and the other end is grounded, one end of the inductor is connected to the ground pin of the second interface module, and the other end is grounded.

9. The RS485 communication circuit according to claim 8, characterized in that: The second zener diode comprises a transient voltage suppressor diode.

10. The RS485 communication circuit according to claim 1, characterized in that: The first interface module and the second interface module both use double-row female connectors with a 2.54 mm pitch.

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