High reliability and low cost multi-channel rs-422 communication circuit

Abstract

The invention discloses a high-reliability low-cost multichannel RS-422 communication circuit which comprises a signal receiving unit and a signal transmitting unit. The signal receiving unit comprises a photoelectric coupler U1, current limiting resistors, filter capacitors and level clamp diodes, and the signal transmitting unit comprises a transmitting chip U2 and current limiting resistors; RS-422 communication transmitted signals can be transmitted to the transmitting chip U2 from an MCU (microprogrammed logic control unit) in TTL (transistor-transistor logic) level forms and can be converted into differential signals, then the differential signals can be outputted via the second current limiting resistor, currents of RS-422 communication received signals are limited by the first current limiting resistor, voltages of the RS-422 communication received signals are limited by the level clamp diodes, the RS-422 communication received signals are filtered by the filter capacitors andthen are transmitted into the photoelectric coupler U1, light emitting diodes of the photoelectric coupler can be turned on and off under the control, accordingly, the differential signals and TTL level can be converted, and signals can be isolated. According to the scheme, the high-reliability low-cost multichannel RS-422 communication circuit has the advantages that the high-reliability low-costmultichannel RS-422 communication circuit can be applied to RS-422 communication mode circuits on missiles, is high in switching rate and reliability and low in cost and is small and anti-interference, and the like.

Description

technical field [0001] The invention belongs to the technical field of electronic equipment, in particular to a high-reliability and low-cost multi-channel RS-422 communication circuit. Background technique [0002] RS-422 communication is currently the most commonly used communication method on missiles. The common interface forms are: (1) protocol chip + sending isolation transformer + receiving isolation transformer. Cost; (2) Sending chip + receiving chip, this method has no isolation effect, the signal has poor anti-interference ability and low reliability, which affects the normal communication between the upper computer and the lower computer. Contents of the invention [0003] The purpose of the present invention is to propose a circuit that meets the requirements of multi-channel and strong anti-interference ability, and can well meet the requirements of high reliability and low cost, aiming at the characteristics of RS-422 communication on missiles. [0004] The...

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Problems solved by technology

[0002] RS-422 communication is currently the most commonly used communication method on missiles. The common interface forms are: (1) protocol chip + sending isolation transformer + receiving isolation transformer. Cost; (2) Sending chip + receiving chip, this method has no isolation effect, the signal has poor anti-interference ability and low reliability, which affects the normal communication between the upper computer and the lower computer

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