CN202872758U - Intrinsically safe serial port communication isolating circuit for mining - Google Patents

Abstract

The utility model relates to the isolation and conversion technology of non-intrinsically safe and intrinsically safe RS232 signals of underground electric products in coal mines, in particular to a mining intrinsically safe serial port communication isolation circuit. Both the signal sending end and the receiving end use optocouplers for isolation and signal conversion. The isolation of the optocoupler can withstand DC 1500V withstand voltage, which meets the withstand voltage requirements of intrinsically safe circuits. The sending end converts the DC voltage signal into a DC current signal through the photocoupler for transmission, and the receiving end converts it into a DC voltage signal through the photocoupler and then sends it to the ICL232 to convert it into a standard RS232 voltage signal. The communication signal is isolated by two photocouplers to ensure the reliability of the signal. The intrinsically safe type and the non-intrinsically safe type are converted from voltage transmission to current transmission, which effectively improves the anti-interference performance and makes signal transmission more stable.

Description

Mine Intrinsically Safe Serial Port Communication Isolation Circuit

technical field

The utility model relates to an RS232 communication isolation technology for intrinsically safe and non-intrinsically safe circuits in mine electrical products, in particular to an intrinsically safe serial port communication isolation circuit for mines.

Background technique

The new mining electrical products mostly use large-screen true-color LCD displays. This type of display has a standard RS232 interface, and the RS232 communication circuit is a non-intrinsically safe circuit. It needs to be isolated and converted into an intrinsically safe circuit to communicate with the intrinsically safe communication device. for data communication.

Large-screen true-color liquid crystal display, because it is a non-intrinsically safe component, needs to be installed in a flame-proof chamber, and the host computer for data communication with it is generally an intrinsically safe circuit, which needs to be installed in an intrinsically safe chamber. This communication isolation circuit is designed for the communication isolation problem.

Contents of the invention

The purpose of this utility model is to provide an intrinsically safe serial port communication isolation circuit for mines, which converts the DC voltage signal of the intrinsically safe serial port communication through a photocoupler into a DC current signal and transmits it to the intrinsically safe circuit. Then convert it into a DC voltage signal through a photocoupler, and then send it to the level conversion circuit ICL232 chip to convert it into a standard RS232 voltage signal, and input it to a non-intrinsically safe communication device, which effectively improves the anti-interference performance and makes the signal transmission stable and reliable. .

The technical scheme of the utility model is: including a level conversion circuit, a co-directional driver and four photoelectric couplers; IN-TXD and IN-RXD are the signal sending end and receiving end of intrinsically safe serial port communication, and OUT-TXD , OUT-RXD is the signal sending end and receiving end of the non-intrinsically safe serial port communication, U3, U4, U6, U7 are photocouplers TLP521-1, U5A is the same direction driver 75451, U2 is the RS232 level conversion circuit ICL232;

Intrinsically safe signal transmitter IN-TXD is connected to pin 2 of optocoupler U7, after being converted into a DC current signal by optocoupler U7, it is sent by pin 3 of optocoupler U7, and then connected to pin 1 of optocoupler U4 , converted into a DC voltage signal by the optocoupler U4 and sent by pin 4, respectively connected to the pull-up resistor R2 and pin 10 of the level conversion circuit U2, and then converted into a standard RS232 voltage signal by the level conversion circuit U2 by 7 The pin is connected to the non-intrinsically safe signal transmitting terminal OUT-TXD; the non-intrinsically safe signal receiving terminal OUT-RXD is connected to the 8-pin of the level conversion circuit U2, and the level conversion circuit U2 converts the RS232 voltage signal into a DC voltage signal It is sent by pin 9, then connected to pin 1 and pin 2 of the co-directional driver U5A to receive, and then sent by pin 3 of the same-directional driver U5A, connected to pin 2 of the optocoupler U3, converted into a DC current signal, and sent by the optocoupler The 4-pin transmission of U3 is connected to the 2-pin reception of the optocoupler U6, which is converted into a DC voltage signal, sent by the 4-pin of the optocoupler U6, and connected to the pull-up resistor R17 and the intrinsically safe signal receiving terminal IN-RXD respectively.

The beneficial effect of the utility model is: the communication signal can bear the withstand voltage of 1500V through the isolation of two photoelectric couplers, which ensures the reliability of the signal, and the transmission of intrinsically safe and non-intrinsically safe signals is effectively converted into a DC current signal. It improves the anti-interference and makes the signal transmission more stable.

The technical scheme of the utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1: Structural schematic diagram of the utility model.

Detailed ways

The utility model converts the intrinsically safe (hereinafter referred to as intrinsically safe) serial port communication DC voltage signal through a photoelectric coupler and converts it into a direct current signal and transmits it to a non-intrinsically safe (hereinafter referred to as non-intrinsically safe) circuit. The photoelectric coupler converts it into a DC voltage signal, and then sends it to the level conversion circuit ICL232 chip to convert it into a standard RS232 voltage signal, and then inputs it to a non-intrinsically safe communication device.

As shown in Figure 1, the utility model includes a level conversion circuit, a co-directional driver and four photocouplers; +5V and +12V are intrinsically safe DC power supplies, and +5VA is a non-intrinsically safe DC power supply; IN-TXD , IN-RXD is the signal sending end and receiving end of intrinsically safe RS232 serial port communication; OUT-TXD and OUT-RXD are the signal sending end and receiving end of non-intrinsically safe RS232 serial port communication; U3 and U4 are Non-intrinsically safe optocoupler TLP521-1, U6 and U7 are intrinsically safe optocoupler TLP521-1; U5A is the same direction driver 75451; U2 is the RS232 level conversion circuit ICL232.

Intrinsically safe signal sending terminal IN-TXD is connected to pin 2 of optocoupler U7, which is converted into a DC current signal by optocoupler U7 and sent by pin 3 of optocoupler U7, and then connected to pin 1 of optocoupler U4. It is converted into a DC voltage signal by the photocoupler U4 and sent by pin 4, respectively connected to the pull-up resistor R2 and pin 10 of the level conversion circuit U2, and then converted into a standard RS232 voltage signal by the level conversion circuit U2 by pin 7 The sending is connected to the non-intrinsically safe signal sending terminal OUT-TXD; the other end of the pull-up resistor R2 is connected to +5VA; pin 1 and pin 4 of U7 are respectively connected to +5V and +12V through resistors R19 and R18.

The non-intrinsically safe signal receiving end OUT-RXD is connected to pin 8 of the level conversion circuit U2, and the level conversion circuit U2 (ICL232 chip) converts the RS232 voltage signal into a DC voltage signal, which is sent by pin 9 and connected to U5A in the same direction The pins 1 and 2 of the driver receive, and then sent by pin 3 of the same direction driver U5A, connected to pin 2 of the photocoupler U3, converted into a DC current signal, sent by pin 4 of the photocoupler U3, and connected to the pin of the photocoupler U6 2-pin receiving, converted into a DC voltage signal, sent by the 4-pin of the photocoupler U6, respectively connected to the pull-up resistor R17 and the intrinsically safe signal receiving terminal IN-RXD; the other end of the pull-up resistor R17 is connected to +5V; U6’s Pin 1 is connected to +12V through current limiting resistor R16; pin 1 of U3 is connected to +5VA power supply through current limiting resistor R1.

The working principle of the utility model is: the photoelectric coupler is used for isolation and signal conversion at both the signal sending end and the receiving end. The converter converts it into a DC voltage signal and then sends it to the ICL232 to convert it into a standard RS232 voltage signal. When the intrinsically safe signal transmitting terminal IN-TXD is a high-level signal, the photocoupler U7 is not conducting, the signal line TXD (that is, U7 pin 3) has no current signal, and the receiving terminal photocoupler U4 is not conducting, U4 The 4-pin is connected to the non-intrinsically safe power supply +5VA through the pull-up resistor R2, and the output is a high-level signal, and then converted into a standard RS232 high-level signal output by the level conversion circuit U2 (ICL232 chip) and connected to the non-intrinsically safe Type signal sending terminal OUT-TXD. When IN-TXD is a low-level signal, the photocoupler U7 is turned on, the 3-pin signal line TXD of U7 has a current signal, the receiving end photocoupler U4 is turned on, and the 4-pin of U4 is output as a low level through the 3-pin ground The signal is then converted into a standard RS232 low-level signal by the level conversion circuit U2 (ICL232 chip) and output to the non-intrinsically safe signal sending terminal OUT-TXD.

Claims (1)

1. A mining intrinsically safe serial port communication isolation circuit is characterized in that: it includes a level conversion circuit, a codirectional driver and four optocouplers; IN-TXD and IN-RXD are intrinsically safe serial ports The signal sending end and receiving end of communication, OUT-TXD, OUT-RXD are the signal sending end and receiving end of non-intrinsically safe serial port communication, U3, U4, U6, U7 are photocoupler TLP521-1, U5A is Co-directional driver 75451, U2 is RS232 level conversion circuit ICL232; Intrinsically safe signal transmitter IN-TXD is connected to pin 2 of optocoupler U7, after being converted into a DC current signal by optocoupler U7, it is sent by pin 3 of optocoupler U7, and then connected to pin 1 of optocoupler U4 , converted into a DC voltage signal by the optocoupler U4 and sent by pin 4, respectively connected to the pull-up resistor R2 and pin 10 of the level conversion circuit U2, and then converted into a standard RS232 voltage signal by the level conversion circuit U2 by 7 The pin is connected to the non-intrinsically safe signal transmitting terminal OUT-TXD; the non-intrinsically safe signal receiving terminal OUT-RXD is connected to the 8-pin of the level conversion circuit U2, and the level conversion circuit U2 converts the RS232 voltage signal into a DC voltage signal It is sent by pin 9, then connected to pin 1 and pin 2 of the co-directional driver U5A to receive, and then sent by pin 3 of the co-directional driver U5A, connected to pin 2 of the optocoupler U3, converted into a DC current signal, and sent by the optocoupler U3 The 4-pin transmission of the photocoupler U6 is connected to the 2-pin reception of the optocoupler U6, converted into a DC voltage signal, sent by the 4-pin of the photocoupler U6, and connected to the pull-up resistor R17 and the intrinsically safe signal receiving terminal IN-RXD respectively.

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