CN210640890U

CN210640890U - Automatic RS232 and RS485 isolation conversion device of receiving and dispatching

Info

Publication number: CN210640890U
Application number: CN201921971973.4U
Authority: CN
Inventors: 陈雯雅; 王昌盛; 荣相; 史晗; 张德正; 文敬忠
Original assignee: Tiandi Changzhou Automation Co Ltd; Changzhou Research Institute of China Coal Technology and Engineering Group Corp
Current assignee: Tiandi Changzhou Automation Co Ltd; Changzhou Research Institute of China Coal Technology and Engineering Group Corp
Priority date: 2019-11-15
Filing date: 2019-11-15
Publication date: 2020-05-29
Anticipated expiration: 2029-11-15

Abstract

The utility model provides an automatic RS232 and RS485 that receive and dispatch keep apart conversion equipment, including power isolation unit, RS232 interface unit, keep apart the transmission unit, RS485 interface unit, RS232 interface unit is through keeping apart transmission unit and RS485 interface unit both way communication, and power isolation unit provides two ways of DC5V power of keeping apart and provides working power supply for RS232 interface unit, RS485 interface unit and isolation transmission unit, and during the use, RS232 interface unit and RS485 interface unit are connected with the external communication equipment electricity; the power isolation unit is connected with an external DC5V power supply. The utility model discloses an overall circuit structural design, RS232 and RS485 interface unit that can effectively solve the existence of current device of the same kind easily produce the problem of indiscriminate sign indicating number easily appear when crosstalking and common mode interference and full duplex communication.

Description

Automatic RS232 and RS485 isolation conversion device of receiving and dispatching

Technical Field

The utility model relates to a bus communication conversion equipment technical field, concretely relates to automatic switching device is kept apart with RS485 to RS232 of receiving and dispatching.

Background

The RS232 bus adopts an unbalanced transmission mode, namely single-ended communication, and the RS485 bus adopts balanced transmission and differential reception, so that the capability of inhibiting common-mode interference is realized; the RS232 bus is suitable for communication among local devices, the transmission distance generally does not exceed 20m, and the maximum transmission distance 1219m of the RS485 bus is obtained; because the transmission modes between the two devices are different, the device adopting RS232 bus transmission cannot directly realize mutual communication with the device adopting RS485 bus transmission, and in order to solve the problem, a communication conversion device is usually additionally arranged between the RS232 bus transmission device and the RS485 bus transmission device to realize the mutual communication between the two devices. The following problems are mostly existed in the current communication conversion devices: firstly, an RS232 interface part and an RS485 interface part in the device are directly converted and communicated without isolation, and working power supplies of the RS232 interface part and the RS485 interface part are not isolated, so that crosstalk and common mode interference are easily generated between the two parts; secondly, the problem of code confusion is easy to occur during full duplex communication.

SUMMERY OF THE UTILITY MODEL

The utility model aims at: aiming at the technical problems in the prior art, the improved automatic transmitting and receiving RS232 and RS485 isolation conversion device capable of solving the technical problems is provided.

The technical scheme of the utility model is that: the utility model discloses an automatic RS232 and RS485 of receiving and dispatching keep apart conversion equipment, including RS232 interface unit and RS485 interface unit, above-mentioned RS232 interface unit and RS485 interface unit are equipped with internal communication end, external communication end and the positive negative pole of power end respectively, its characterized in that: the device also comprises an isolation transmission unit and a power isolation unit; the isolation transmission unit is provided with a first communication end, a second communication end, a first power end anode and a second power end cathode, the power isolation unit is provided with a power input end anode and a power input end cathode, a first power output end anode and a second power output end anode and a power input end cathode, and the power input end anode and the power input end cathode of the power isolation unit are also the first power output end anode and the power output end cathode;

the RS232 interface unit is in two-way communication with the first communication end of the isolation transmission unit through the internal communication end, the RS485 interface unit is in two-way communication with the second communication end of the isolation transmission unit through the isolation transmission unit, the positive and negative poles of the power end of the RS232 interface unit and the positive and negative poles of the first power end of the isolation transmission unit are correspondingly and electrically connected with the positive and negative poles of the first power output end of the power isolation unit, and the positive and negative poles of the power end of the RS485 interface unit and the positive and negative poles of the second power end of the isolation transmission unit are correspondingly and electrically connected with the positive and negative poles of the second power output end of the power isolation unit; when the device is used, the RS232 interface unit and the RS485 interface unit are correspondingly and electrically connected with corresponding external communication equipment through the RS232 bus and the RS485 bus respectively; the power input of the power isolation unit is electrically connected to an external DC5V power supply.

The further scheme is as follows: the isolation transmission unit comprises an optocoupler U9, an optocoupler U10, 5 resistors R9-R13, a capacitor C33, a capacitor C34 and a triode Q3; the types of the optical coupler U9 and the optical coupler U10 are both PC410, the optical coupler U9 and the optical coupler U10 are respectively provided with No. 1-6 pins,

the pin 6 of the optocoupler U9, one end of the resistor R10 and one end of the capacitor C33 are provided with a common contact, the common contact and one end of the resistor R11 jointly form a first power supply end anode of the isolation transmission unit, the pin 6 of the optocoupler U10, one end of the resistor R13 and one end of the capacitor C34 are provided with a common contact, the common contact and one end of the resistor R9 jointly form a second power supply end anode of the isolation transmission unit, and the other end of the resistor R9 and the other end of the resistor R11 are respectively and correspondingly electrically connected with the pin 1 of the optocoupler U9 and the pin 1 of the optocoupler U10; a pin 5 of the optocoupler U9 and the other end of the resistor R10 are provided with a common contact, and the common contact and one end of the resistor R12 jointly form a first communication end of the isolation transmission unit; a pin 5 of the optocoupler U10 and the other end of the resistor R13 are provided with a common connection point, and the common connection point and a pin 3 of the optocoupler U9 jointly form a second communication end of the isolation transmission unit; the pin 4 of the optocoupler U9 and the other end of the capacitor C33 are provided with a common connection point, the common connection point and the emitter of the triode Q3 jointly form a first power supply end cathode of the isolation transmission unit, the pin 4 of the optocoupler U10 and the other end of the capacitor C34 are provided with a common connection point, the common connection point forms a second power supply end cathode of the isolation transmission unit, the other end of the resistor R12 is electrically connected with the base electrode of the triode Q3, and the collector of the triode Q3 is electrically connected with the pin 3 of the optocoupler U10.

The further scheme is as follows: the power isolation unit comprises an isolation power module U7, a capacitor C25, a capacitor C50, an electrolytic capacitor C26, an electrolytic capacitor C27, a TVS tube D16 and a resistor R36, the isolation power module U7 is B0505S and is provided with No. 1-4 pins,

the pin No. 1 of the isolation power module U7, the positive electrode of the electrolytic capacitor C26 and one end of the capacitor C25 are provided with a common contact, the common contact is the positive electrode of the power input end and the positive electrode of the first power output end of the power isolation unit, the pin No. 2 of the isolation power module U7, the negative electrode of the electrolytic capacitor C26 and the other end of the capacitor C25 are provided with a common contact, the common contact is the negative electrode of the power input end and the negative electrode of the first power output end of the power isolation unit, the pin No. 4 of the isolation power module U7, one end of the capacitor C50, the positive electrode of the electrolytic capacitor C27, one end of the TVS tube D16 and one end of the resistor R36 are provided with a common contact, the common contact is the positive electrode of the second power output end of the power isolation unit, the pin No. 3 of the isolation power module U7, the other end of the capacitor C50, the negative electrode of the electrolytic capacitor C27, the other end of the, the common contact is the cathode of the second power output end of the power isolation unit.

The further scheme is as follows: the RS485 interface unit comprises an integrated chip U12, a NOT gate circuit U11, a diode D6, 6 resistors R14-R19, a TVS tube D7, a TVS tube D8, a TVS tube D9, a capacitor C35, a capacitor C39, a common-mode inductor LP2, a matching resistor selective connection terminal J3 and a short-circuit cap; the integrated chip U12 is a MAX3085 transceiver, and the integrated chip U12 is provided with No. 1-8 pins; the NOT gate circuit U11 is a 74HC14 integrated chip, and is provided with 3 NOT gate circuits including U11A, U11B and U11C, and the NOT gate circuit U11 is provided with No. 1-6 pins; the model of the common-mode inductor LP2 is SF090250YLB, the common-mode inductor LP2 is provided with No. 1-4 pins, and the matching resistor selective connection terminal J3 is provided with No. 1-3 pins;

the pin 1 of the integrated chip U12 and the pin 3 of the NOT gate U11 together form the internal communication end of the RS485 interface unit, the pin 2 and the pin 3 of the integrated chip U12 and the pin 2 of the NOT gate U11 have a common connection point, the pin 1 of the NOT gate U11, one end of the capacitor C35, one end of the resistor R14 and the anode of the diode D6 have a common connection point, the cathode of the diode D6, the other end of the resistor R14, the pin 4 of the integrated chip U12 and the pin 6 of the NOT gate U11 have a common connection point, the pin 4 of the NOT gate U11 is electrically connected with the pin 5, the pin 8 of the integrated chip U12, one end of the resistor R15 and one end of the capacitor C39 have a common connection point, the common connection point is the power supply end of the RS485 interface unit, the pin 6 of the integrated chip U12, the other end of the resistor R15, one end of the TVS tube D7, one end of the TVS tube D2 and the common mode inductor 2 have a common connection point 67 9 6, the pin 7 of the integrated chip U12, one end of the resistor R16, one end of the TVS tube D8, the other end of the TVS tube D9, and the pin 2 of the common-mode inductor LP2 have a common contact, and the pin 5 of the integrated chip U12, the other end of the resistor R16, the other end of the TVS tube D7, the other end of the TVS tube D8, the other end of the capacitor C35, and the other end of the capacitor C39 jointly form a power supply terminal cathode of the RS485 interface unit; pin 4 of the common mode inductor LP2 is electrically connected with one end of a resistor R17, pin 3 of the common mode inductor LP2 is electrically connected with one end of a resistor R18, the other end of the resistor R18 and one end of a resistor R19 are provided with a common contact a, the other end of the resistor R19 is electrically connected with pin 3 of a matching resistor selection terminal J3, the other end of the resistor R17 and pin 2 of a matching resistor selection terminal J3 are provided with a common contact B, and the common contact a and the common contact B jointly form an external communication end of the RS485 interface unit; the connection and disconnection between the 3 pin and the 2 pin of the matching resistance selective connection terminal J3 are correspondingly controlled by the insertion and the extraction of the short-circuit cap.

The further scheme is as follows: the RS232 interface unit comprises an integrated chip U8, a capacitor C28, a capacitor C29, a capacitor C30, a capacitor C31 and a capacitor C32, wherein the integrated chip U8 is a single power level conversion chip MAX202, the integrated chip U8 is provided with No. 1-16 pins,

the pin 1 and the pin 3 of the integrated chip U8 are connected through a capacitor C31, the pin 4 and the pin 5 of the integrated chip U8 are connected through a capacitor C30, the pin 16 of the integrated chip U8 and one end of the capacitor C32 are provided with a common contact, the common contact and one end of the capacitor C28 jointly form a power supply end anode of the RS232 interface unit, the other end of the capacitor C28 is electrically connected with the pin 2 of the integrated chip U8, the pin 6 of the integrated chip U8 is electrically connected with one end of the capacitor C29, the other end of the capacitor C32 and the pin 15 of the integrated chip U8 are provided with a common contact, the common contact and the other end of the capacitor C29 jointly form a power supply end cathode of the RS232 interface unit, the pin 7 and the pin 8 of the integrated chip U8 jointly form an external communication end of the RS232 interface unit, and the pin 9 and the pin 10 of the integrated chip U8 jointly form an internal communication end of the RS232 interface unit.

The utility model discloses has positive effect: (1) the utility model discloses an automatic RS232 and RS485 of receiving and dispatching keep apart conversion equipment, it is through setting up between RS232 interface unit and RS485 interface unit and keep apart the transmission unit, thereby keep apart the interference that can effectively avoid RS232 interface unit through the opto-coupler that keeps apart the transmission unit and transmit RS485 interface unit, and keep apart the DC5V power that the unit provided two tunnel isolations through setting up the power and provide working power supply for RS232 interface unit and RS485 interface unit and keep apart the transmission unit, can effectively restrain crosstalk and common mode interference between RS232 interface unit and the RS485 interface unit. (2) The utility model discloses an automatic RS232 and RS485 isolation conversion equipment of receiving and dispatching, it is through setting up delay circuit at RS485 interface unit, can effectively solve the problem that the indiscriminate sign indicating number easily appears in current device of the same kind when "full duplex communication" operating condition. (3) The utility model discloses an automatic RS232 and RS485 isolation conversion equipment of receiving and dispatching, its overall structure is simple relatively, and the cost is lower, is suitable for popularization and application.

Drawings

Fig. 1 is a block diagram of the circuit structure of the present invention;

FIG. 2 is an electrical schematic diagram of the RS232 interface unit of FIG. 1;

FIG. 3 is an electrical schematic diagram of the RS485 interface unit of FIG. 1;

FIG. 4 is an electrical schematic of the isolation transmission unit of FIG. 1;

fig. 5 is a circuit diagram of the power isolation unit of fig. 1.

The reference numbers in the above figures are as follows:

the device comprises an RS232 interface unit 10, an RS485 interface unit 20, an isolation transmission unit 30 and a power isolation unit 40.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

(example 1)

Referring to fig. 1, the automatic transceiving RS232 and RS485 isolation conversion device of the present embodiment mainly includes an RS232 interface unit 10, an RS485 interface unit 20, an isolation transmission unit 30, and a power isolation unit 40.

The RS232 interface unit 10 and the RS485 interface unit 20 are respectively provided with an internal communication end, an external communication end and a power end anode and cathode, the isolation transmission unit 30 is provided with a first communication end, a second communication end, a first power end anode and a second power end cathode, the power isolation unit 40 is provided with a power input end anode and cathode, a first power output end anode and cathode, and the power input end anode and cathode of the power isolation unit 40 are also the first power output end anode and cathode; the RS232 interface unit 10 is in two-way communication with the first communication end of the isolation transmission unit 30 through the internal communication end thereof, the RS485 interface unit 20 is in two-way communication with the second communication end of the isolation transmission unit 30 through the isolation transmission unit 30, the positive and negative power ends of the RS232 interface unit 10 and the positive and negative first power ends of the isolation transmission unit 30 are correspondingly and electrically connected with the positive and negative first power output end of the power isolation unit 40, and the positive and negative power ends of the RS485 interface unit 20 and the positive and negative second power ends of the isolation transmission unit 30 are correspondingly and electrically connected with the positive and negative second power output end of the power isolation unit 40; when in use, the RS232 interface unit 10 and the RS485 interface unit 20 are respectively and correspondingly electrically connected with first and second external communication devices (not shown in the figure) through an RS232 bus and an RS485 bus; the power input of the power isolation unit 40 is electrically connected to an external DC5V power supply.

Referring to fig. 2, the RS232 interface unit 10 is mainly composed of an integrated chip U8, a capacitor C28, a capacitor C29, a capacitor C30, a capacitor C31, and a capacitor C32. The integrated chip U8 is a single power level shift chip MAX202, and the integrated chip U8 has pins 1-16.

No. 1 pin and No. 3 pin of the integrated chip U8 are connected through a capacitor C31, No. 4 pin and No. 5 pin of the integrated chip U8 are connected through a capacitor C30, the No. 16 pin of the integrated chip U8 and one end of the capacitor C32 are provided with a common contact, the common contact and one end of the capacitor C28 together form a power supply terminal anode (denoted by VCC5 in fig. 2) of the RS232 interface unit 10, the other end of the capacitor C28 is electrically connected to pin 2 of the integrated chip U8, pin 6 of the integrated chip U8 is electrically connected to one end of the capacitor C29, the other end of the capacitor C32 and pin 15 of the integrated chip U8 have a common contact, the common contact and the other end of the capacitor C29 together form a power supply terminal cathode of the RS232 interface unit 10, the pin 7 and the pin 8 (denoted as RXD and TXD in fig. 2, respectively) of the integrated chip U8 together form an external communication terminal of the RS232 interface unit 10, and the pin 9 and the pin 10 (denoted as RXD1 and TXD1, respectively, in fig. 2) of the integrated chip U8 together form an internal communication terminal of the RS232 interface unit 10.

Referring to fig. 3, the RS485 interface unit 20 is mainly composed of an integrated chip U12, a not gate circuit U11, a diode D6, 6 resistors R14-R19, a TVS (i.e., a transient diode) D7, a TVS D8, a TVS D9, a capacitor C35, a capacitor C39, a common mode inductor LP2, a matching resistor selection terminal J3, and a shorting cap (not shown). The integrated chip U12 is a MAX3085 transceiver, the integrated chip U12 is provided with No. 1-8 pins, the NOT gate circuit U11 is a 74HC14 integrated chip which is provided with 3 NOT gate circuits including U11A, U11B and U11C, the U11 is provided with No. 1-6 pins, the model of the common mode inductor LP2 is SF090250YLB, the common mode inductor LP2 is provided with No. 1-4 pins, and the matching resistance selective connection terminal J3 is provided with No. 1-3 pins.

Pin 1 of the integrated chip U12 (labeled TXD2 in fig. 3) and pin 3 of the nand gate U11 (labeled RXD2 in fig. 3) jointly form an internal communication terminal of the RS485 interface unit 20,

pins

2 and 3 of the integrated chip U12 and pin 2 of the nand gate U11 have a common connection point, pin 1 of the nand gate U11, one end of the capacitor C35, one end of the resistor R14 and the anode of the diode D6 have a common connection point, the cathode of the diode D6, the other end of the resistor R14, pin 4 of the integrated chip U12 and pin 6 of the nand gate U11 have a common connection point, pin 4 of the nand gate U11 is electrically connected to pin 5, pin 8 of the integrated chip U12, one end of the resistor R15 and one end of the capacitor C39 have a common connection point, which is the aforementioned positive power supply terminal of the RS485 interface unit 20 (labeled VCC positive terminal of VCC51 in fig. 3), and pin 15 of the integrated chip U12, pin 6 of the resistor U15 and pin 466, One end of the TVS tube D7, one end of the TVS tube D9, and the pin 1 of the common mode inductor LP2 have a common contact, the pin 7 of the integrated chip U12, one end of the resistor R16, one end of the TVS tube D8, the other end of the TVS tube D9, and the pin 2 of the common mode inductor LP2 have a common contact, and the pin 5 of the integrated chip U12, the other end of the resistor R16, the other end of the TVS tube D7, the other end of the TVS tube D8, the other end of the capacitor C35, and the other end of the capacitor C39 together form the power terminal cathode of the RS485 interface unit 20 (indicated by GND1 in fig. 3); pin 4 of the common mode inductor LP2 is electrically connected to one end of the resistor R17, pin 3 of the common mode inductor LP2 is electrically connected to one end of the resistor R18, the other end of the resistor R18 and one end of the resistor R19 have a common contact a, the other end of the resistor R19 is electrically connected to pin 3 of the matching resistor selection terminal J3, the other end of the resistor R17 and pin 2 of the matching resistor selection terminal J3 have a common contact B, and the common contact a and the common contact B together form the external communication end of the RS485 interface unit 20. The resistor R19 is used as a matching resistor and is controlled to be switched in or switched off by a matched short-circuit cap through the matching resistor selective connection terminal J3, when the transmission distance of the 485 bus exceeds a fixed length, the short-circuit cap is inserted to switch on the 3 pins and the 2 pins of the matching resistor selective connection terminal J3, and the resistor R19 is switched in to ensure the stability of the 485 bus.

Referring to fig. 4, the isolation transmission unit 30 mainly includes 5 resistors including an optocoupler U9, an optocoupler U10, resistors R9 to R13, a capacitor C33, a capacitor C34, and a transistor Q3. The type of opto-coupler U9 and opto-coupler U10 is PC410, and opto-coupler U9 and opto-coupler U10 have 1 ~ 6 No. feet respectively.

A pin 6 of the optocoupler U9, one end of the resistor R10 and one end of the capacitor C33 are provided with a common contact, the common contact and one end of the resistor R11 jointly form a first power supply end anode (denoted by VCC5 in FIG. 4) of the isolation transmission unit 30, a pin 6 of the optocoupler U10, one end of the resistor R13 and one end of the capacitor C34 are provided with a common contact, the common contact and one end of the resistor R9 jointly form a second power supply end anode (denoted by VCC51 in FIG. 4) of the isolation transmission unit 30, and the other end of the resistor R9 and the other end of the resistor R11 are respectively and correspondingly electrically connected with a pin 1 of the optocoupler U9 and a pin 1 of the optocoupler U10; a pin 5 of the optical coupler U9 and the other end of the resistor R10 have a common contact (denoted by TXD1 in fig. 4), and the common contact and one end of the resistor R12 (denoted by RXD1 in fig. 4) jointly form a first communication end of the isolation transmission unit 30; a pin 5 of the optical coupler U10 and the other end of the resistor R13 have a common contact (labeled RXD2 in fig. 4), and the common contact and a pin 3 of the optical coupler U9 (labeled TXD2 in fig. 4) jointly form a second communication end of the isolation transmission unit 30; the pin 4 of the optocoupler U9 and the other end of the capacitor C33 have a common connection point, the common connection point and the emitter of the transistor Q3 together form the first power supply terminal cathode (labeled GND in fig. 4) of the isolation transmission unit 30, the pin 4 of the optocoupler U10 and the other end of the capacitor C34 have a common connection point, the common connection point forms the second power supply terminal cathode (labeled GND1 in fig. 4) of the isolation transmission unit 30, the other end of the resistor R12 is electrically connected with the base of the transistor Q3, and the collector of the transistor Q3 is electrically connected with the pin 3 of the optocoupler U10.

Referring to fig. 5, the power isolation unit 40 is mainly composed of an isolation power module U7, a capacitor C25, a capacitor C50, an electrolytic capacitor C26, an electrolytic capacitor C27, a TVS tube D16, and a resistor R36. The isolated power supply module U7 is B0505S and has No. 1-4 pins.

Pin 1 of the isolation power module U7, the positive electrode of the electrolytic capacitor C26 and one end of the capacitor C25 have a common connection point, the common connection point is the positive electrode of the power input end of the aforementioned power isolation unit 40, and is also the positive electrode of the first power output end of the power isolation unit 40 (denoted VCC5 in fig. 5), pin 2 of the isolation power module U7, the negative electrode of the electrolytic capacitor C26 and the other end of the capacitor C25 have a common connection point, the common connection point is the negative electrode of the power input end of the aforementioned power isolation unit 40 and is also the negative electrode of the first power output end of the power isolation unit 40 (denoted GND in fig. 5), pin 4 of the isolation power module U7, one end of the capacitor C50, the positive electrode of the electrolytic capacitor C27, one end of the TVS tube D16 and one end of the resistor R36 have a common connection point, the common connection point is the positive electrode of the aforementioned second power output end of the power isolation unit 40 (denoted VCC51 in, the pin 3 of the isolated power module U7, the other end of the capacitor C50, the negative electrode of the electrolytic capacitor C27, the other end of the TVS tube D16, and the other end of the resistor R36 have a common node, which is the negative electrode of the second power output terminal of the aforementioned power isolation unit 40 (marked as GND1 in fig. 5).

The operation principle of the automatic transmitting and receiving RS232 and RS485 isolation conversion device in the embodiment when in use is briefly described as follows:

during operation, the power isolation unit 40 provides two isolated DC5V power supplies to provide operating power for the RS232 interface unit 10, the RS485 interface unit 20, and the isolation transmission unit 30 is provided, so that crosstalk and common mode interference between the RS232 interface unit 10 and the RS485 interface unit 20 can be effectively suppressed. The RS232 interface unit 10 is configured to convert a differential signal sent by a first external communication device connected thereto via the RS232 bus into a TTL level through its integrated chip U8 (i.e., MAX 202) and send the TTL level to the RS485 interface unit 20 through the isolation transmission unit 30, and convert the TTL level sent by the RS485 interface unit 20 via the isolation transmission unit 30 into a differential signal through the integrated chip U8 and send the differential signal to the first external communication device via the RS232 bus. The RS485 interface unit 20 is configured to convert a differential signal sent by a second external communication device connected thereto via the RS485 bus into a TTL level via the integrated chip U12 (i.e., MAX 3085), and send the TTL level to the RS232 interface unit 10 via the isolation transmission unit 30, and convert the TTL level sent by the RS232 interface unit 10 via the isolation transmission unit 30 into a differential signal via the integrated chip U12, and send the differential signal to the second external communication device via the RS485 bus. Thereby realizing the automatic receiving and transmitting communication between the RS232 and the RS 485.

Referring to fig. 3, in order to solve the problem that code confusion is likely to occur when the existing similar device is in the "full duplex communication" operating state, the RS485 interface unit 20 is provided with a delay circuit composed of a resistor R14, a diode D6 and a capacitor C35, and when the diode D6 is not turned on during operation, T = (R14) × (C35); when conducting, the time constant can be extremely shortened by only the operating impedance of the diode D6. When data 1 is transmitted, RXD2 is at high level, the diode D6 is not turned on, the time constant is T = (R14) × (C35), DE is still at high level, the driver is enabled, DI is at high level, the driver drives output a to be 1, B to be 0, and logic 1 is output. Thereby avoiding the occurrence of messy codes during the 'full duplex' operation.

The above embodiments are illustrative of the specific embodiments of the present invention, but not limiting to the present invention, and those skilled in the relevant art can also make various changes and modifications to obtain the equivalent technical solutions without departing from the spirit and scope of the present invention, so that all equivalent technical solutions should fall under the protection scope of the present invention.

Claims

1. The utility model provides an automatic RS232 and RS485 isolation conversion equipment who receives and dispatches, includes RS232 interface unit and RS485 interface unit, RS232 interface unit and RS485 interface unit are equipped with respectively to the positive negative pole of interior communication terminal, external communication terminal and power end, its characterized in that: the device also comprises an isolation transmission unit and a power isolation unit; the isolation transmission unit is provided with a first communication end, a second communication end, a first power end anode and a second power end cathode, the power isolation unit is provided with a power input end anode and a power input end cathode, a first power output end anode and a second power output end anode and a power input end cathode of the power isolation unit are also the first power output end anode and the first power output end cathode;

the RS232 interface unit is in two-way communication with the first communication end of the isolation transmission unit through the internal communication end, the RS485 interface unit is in two-way communication with the second communication end of the isolation transmission unit through the internal communication end, the positive and negative poles of the power end of the RS232 interface unit and the positive and negative poles of the first power end of the isolation transmission unit are correspondingly and electrically connected with the positive and negative poles of the first power output end of the power isolation unit, and the positive and negative poles of the power end of the RS485 interface unit and the positive and negative poles of the second power end of the isolation transmission unit are correspondingly and electrically connected with the positive and negative poles of the second power output end of the power isolation; when the device is used, the RS232 interface unit and the RS485 interface unit are correspondingly and electrically connected with corresponding external communication equipment through the RS232 bus and the RS485 bus respectively; the power input of the power isolation unit is electrically connected to an external DC5V power supply.

2. The automatic RS232 and RS485 isolation conversion device of claim 1, wherein: the isolation transmission unit comprises an optocoupler U9, an optocoupler U10, 5 resistors R9-R13, a capacitor C33, a capacitor C34 and a triode Q3; the types of the optocoupler U9 and the optocoupler U10 are both PC410, the optocoupler U9 and the optocoupler U10 are respectively provided with No. 1-6 pins,

a pin 6 of the optocoupler U9, one end of the resistor R10 and one end of the capacitor C33 are provided with a common connection point, the common connection point and one end of the resistor R11 jointly form a first power supply end anode of the isolation transmission unit, the pin 6 of the optocoupler U10, one end of the resistor R13 and one end of the capacitor C34 are provided with a common connection point, the common connection point and one end of the resistor R9 jointly form a second power supply end anode of the isolation transmission unit, and the other end of the resistor R9 and the other end of the resistor R11 are respectively and correspondingly and electrically connected with a pin 1 of the optocoupler U9 and a pin 1 of the optocoupler U10; a pin 5 of the optocoupler U9 and the other end of the resistor R10 are provided with a common contact, and the common contact and one end of the resistor R12 jointly form a first communication end of the isolation transmission unit; a pin 5 of the optocoupler U10 and the other end of the resistor R13 are provided with a common connection point, and the common connection point and a pin 3 of the optocoupler U9 jointly form a second communication end of the isolation transmission unit; the pin 4 of the optocoupler U9 and the other end of the capacitor C33 are provided with a common connection point, the common connection point and the emitter of the triode Q3 jointly form a first power supply end cathode of the isolation transmission unit, the pin 4 of the optocoupler U10 and the other end of the capacitor C34 are provided with a common connection point, the common connection point forms a second power supply end cathode of the isolation transmission unit, the other end of the resistor R12 is electrically connected with the base electrode of the triode Q3, and the collector of the triode Q3 is electrically connected with the pin 3 of the optocoupler U10.

3. The automatic RS232 and RS485 isolation conversion device of claim 1, wherein: the power isolation unit comprises an isolation power module U7, a capacitor C25, a capacitor C50, an electrolytic capacitor C26, an electrolytic capacitor C27, a TVS tube D16 and a resistor R36, the isolation power module U7 is B0505S and is provided with No. 1-4 pins,

the pin No. 1 of the isolation power module U7, the anode of the electrolytic capacitor C26 and one end of the capacitor C25 are provided with a common connection point, the common connection point is the anode of the power input end and the anode of the first power output end of the power isolation unit, the pin No. 2 of the isolation power module U7, the cathode of the electrolytic capacitor C26 and the other end of the capacitor C25 are provided with a common connection point, the common connection point is the cathode of the power input end and the cathode of the first power output end of the power isolation unit, the pin No. 4 of the isolation power module U7, one end of the capacitor C50, the anode of the electrolytic capacitor C27, one end of the TVS tube D16 and one end of the resistor R36 are provided with a common connection point, the common connection point is the anode of the second power output end of the power isolation unit, the pin No. 3 of the isolation power module U7, the other end of the capacitor C50, the cathode of the electrolytic capacitor C27, the other end of the TVS tube, the common contact is the cathode of the second power output end of the power isolation unit.

4. The automatic RS232 and RS485 isolation conversion device of claim 1, wherein: the RS485 interface unit comprises an integrated chip U12, a NOT gate circuit U11, a diode D6, 6 resistors R14-R19, a TVS tube D7, a TVS tube D8, a TVS tube D9, a capacitor C35, a capacitor C39, a common-mode inductor LP2, a matching resistor selective connection terminal J3 and a short-circuit cap; the integrated chip U12 is a MAX3085 transceiver, and the integrated chip U12 is provided with No. 1-8 pins; the NOT gate circuit U11 is a 74HC14 integrated chip, and is provided with 3 NOT gate circuits including U11A, U11B and U11C, and the NOT gate circuit U11 is provided with No. 1-6 pins; the model of the common-mode inductor LP2 is SF090250YLB, the common-mode inductor LP2 is provided with No. 1-4 pins, and the matching resistor selective connection terminal J3 is provided with No. 1-3 pins;

the pin 1 of the integrated chip U12 and the pin 3 of the NOT gate U11 together form an internal communication end of the RS485 interface unit, the pin 2 and the pin 3 of the integrated chip U12 and the pin 2 of the NOT gate U11 have a common connection point, the pin 1 of the NOT gate U11, one end of the capacitor C35, one end of the resistor R14 and the anode of the diode D6 have a common connection point, the cathode of the diode D6, the other end of the resistor R14, the pin 4 of the integrated chip U12 and the pin 6 of the NOT gate U11 have a common connection point, the pin 4 of the NOT gate U11 is electrically connected with the pin 5, the pin 8 of the integrated chip U12, one end of the resistor R15 and one end of the capacitor C39 have a common connection point, the common connection point is the power supply end of the RS485 interface unit, the pin 6 of the integrated chip U12, the other end of the resistor R15, one end of the TVS tube D7, one end of the TVS 9 and the common mode inductor LP 1 of the common connection point, the pin No. 7 of the integrated chip U12, one end of the resistor R16, one end of the TVS tube D8, the other end of the TVS tube D9 and the pin No. 2 of the common-mode inductor LP2 are provided with a common contact, and the pin No. 5 of the integrated chip U12, the other end of the resistor R16, the other end of the TVS tube D7, the other end of the TVS tube D8, the other end of the capacitor C35 and the other end of the capacitor C39 jointly form a power supply terminal cathode of the RS485 interface unit; pin 4 of the common-mode inductor LP2 is electrically connected with one end of a resistor R17, pin 3 of the common-mode inductor LP2 is electrically connected with one end of a resistor R18, the other end of the resistor R18 and one end of a resistor R19 are provided with a common contact a, the other end of the resistor R19 is electrically connected with pin 3 of a matching resistor selection terminal J3, the other end of the resistor R17 and pin 2 of a matching resistor selection terminal J3 are provided with a common contact B, and the common contact a and the common contact B jointly form an external communication end of the RS485 interface unit; the connection and disconnection between the 3 pin and the 2 pin of the matching resistance selective connection terminal J3 are correspondingly controlled by the insertion and the extraction of the short-circuit cap.

5. The automatic RS232 and RS485 isolation conversion device of claim 1, wherein: the RS232 interface unit comprises an integrated chip U8, a capacitor C28, a capacitor C29, a capacitor C30, a capacitor C31 and a capacitor C32, wherein the integrated chip U8 is a single power level conversion chip MAX202, the integrated chip U8 is provided with No. 1-16 pins,

no. 1 pin and No. 3 pin of the integrated chip U8 are connected through a capacitor C31, No. 4 pin and No. 5 pin of the integrated chip U8 are connected through a capacitor C30, No. 16 pin of the integrated chip U8 and one end of a capacitor C32 are provided with a common contact, the common contact and one end of the capacitor C28 jointly form a power supply end anode of the RS232 interface unit, the other end of the capacitor C28 is electrically connected with No. 2 pin of the integrated chip U8, No. 6 pin of the integrated chip U8 is electrically connected with one end of a capacitor C29, the other end of the capacitor C32 and No. 15 pin of the integrated chip U8 are provided with a common contact, the common contact and the other end of the capacitor C29 jointly form a power supply end cathode of the RS232 interface unit, the No. 7 pin and the No. 8 pin of the integrated chip U8 jointly form an external communication end of the RS232 interface unit, and the No. 9 pin and the No. 10 pin of the integrated chip U8 jointly form an internal communication.