A RS - 232 / RS - 485 half duplex signal conversion circuit, which is characterized in that the circuit consists of serial interface, RS 232 interface chip, chip, Optocoupler RS 485 transceiver, DC DC power supply conversion chip, 4 dial switch, instant suppression diodes, the circuit is composed of the following: RS 232 serial interface COM DB9 data transmission terminal 2 TXD and 14 T1OUT U1 MAX202EPE pins connected to COM, the data receiving end 3 RXD access U1 pins 8 R2IN, COM 5 terminal signal, 7 terminal RTS and 8 terminal CTS short circuit U1 13 pins with access to R1IN, COM9 terminal + 5V the power in U1 The 1, 3 4, 5 ends of both ends, 2, 16, 6, 15 respectively at both ends, connected a capacitor, U1 pins 12 R1OUT pins through resistor R5 access 6N137 optocoupler U2 2 IN + U1, R2OUT and U3 pins 9 pins 3 IN optocoupler connected, U1 pins 11 T1IN access U4 6 VO optocoupler pins, with R9 + 5V through the access resistance; three U2, U3 U4, optocoupler pins 8 VCC + 5V access, 5 GND signal pins, 6 pins VO through a pull-up resistor connected to the VCC, U2 6 RS pins at the same access the 485 transceiver 2, 3 terminal and 4 terminal DI U3 pins 6 to access U7, U4 pins 1 terminal RO 3 to access U7, U7 6, 7 terminal (A, B) for positive and negative data output terminal, U7 terminal A of the 1 terminal DATA R23 since the resumption of insurance access to P2 +, through a pull-up resistor R11 access VCC, U7 terminal B of the 2 terminal DATA self recovery insurance R24 access P2, the pull-down resistor R12 in power, between positive and negative data output terminal 3 and the switch resistance R19, and positive and negative data output respectively by flash suppressor diodes Z1, Z2 power supply, between the power supply and housing Access dial switch 4 and 3 terminal resistance R22, P2. R21 power supply through the pull-down resistor, 4 terminal cabinet.
【技术实现步骤摘要】
本技术涉及一种信号转换电路,特别是指一种RS-232/RS-485半双工信号转换电路。在工业过程自动化工程实施过程中经常需要使用一个或多个驱动器及多个接收器的总线RS-485(或RS-422)。但RS-232只有一个驱动器和一个接收器,经常需要将RS-232接口转换成RS-485接口以满足系统对总线的需求。
技术介绍
目前,有些厂家生产的RS-232/RS-485转换接口由于在设计时的出发点不同,不能完全满足一些对该种产品的特殊需求;有些公司的产品追求低成本,适合民品使用;而有些电路设计虽然功能较多(有些场合并不需要),但其使用温度范围窄,价格高。
技术实现思路
本技术的目的在于避免上述现有技术中的不足之处而提出的一种RS-232/RS-485半双工信号转换电路。本设计是为了解决RS-232接口的传输距离近和只能一对一通讯的缺点,将RS-232接口用转换电路扩展为RS-485接口,达到1500米的传输距离和多点通讯的目的。电源电压为+5V;RS-232/RS-485电路两侧接口之间数据线采用光耦隔离;电源用隔离变压器隔离;手工拨码设定全双工/半双工转换及端接电阻和偏置电阻;RS-485信号波特率小于20Kb/S时的传输距离1500米以上。本技术的目的可以通过以下措施来达到一种RS-232/RS-485半双工信号转换电路,该电路由串行接口、RS-232接口芯片、光耦片、RS-485收发器、DC-DC电源隔离转换芯片、4位拨码开关、瞬间抑制二极管组成,该电路构成如下RS-232串行接口COM DB9数据发送端2 TXD与U1 MAX202EPE管腿14 T1OU ...
【技术保护点】
【技术特征摘要】
【专利技术属性】
技术研发人员:俞凌,庄贵林,
申请(专利权)人:北京安控科技发展有限公司,
类型:实用新型
国别省市:
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