标题: RS485????±??¤·??? ----?ó???§?°
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注册 2003-12-16
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发表于 2004-2-17 11:40  资料  个人空间  短消息  加为好友 
RS485????±??¤·??? ----?ó???§?°

RS485????±??¤·???
The Analysis of Protecting RS485 System
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RS485????EIA??1983?ê?á??????????????????·???±ê×????ú×???±ê×?????·??÷????????·???????·??????¤×÷·?????????????RS485?¨TIA/EIA-485???¨??±???×÷??TIA/EIA-422±ê×??????????????????§???à?????¨32?????????????????????à?÷???????á?§???ü?à???????????à???¨×??ó4000???????????????é?????¨200mV???????????¨???????±?????è????????????×÷?????????ò????±????????è±??ò???????à???????à???¨???·????????????·???????

????????????485???????????????à?ò?????°?ì????×è?????????ò????????????????????????×è????????±??????????·±??¤·??????á??RS485????????????????·?????


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?????????????°???·??????·??????????????¨??RS485????±?????????·??¤??????RS485??????????°???????????????×??????á???????§???·???ò???????????ó????±??????á??????×?????????????????????RS485???·???à???÷??????????

?í????RS485??·??÷??A??B?????????á??????????????????????????±?????????±??????á???????ó??"??"??±?????·???????????????????·??§??-7V??+12V????????·??§????±????????????÷????RS485?????÷?¨???ì??A??B????????×??????????¨??????TTL???????????±A?¨-????B?¨+??????????Vab?¨A-B???ó??+200mV?±??????????????"1"????????????-200mV?±??????????????"0"?????????????????????????±???????????????????????????????????????????ò???±????????·??ú?±??????×???×÷????????·??????quot;??"??×?????×è???????????????§?????????????????????????????§??????????????????????·??ú?±????????·??ú?±???ù???????????????????ú?ú??°????§·ü?????????????±?????????????????????????????????????????????????ù???????????????????????????????????????ó??????????

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??????RS485????????±??é???????÷??±??¤???????×???????·±??????????ù???÷??????????????"??"???????????????÷?¨???÷?????????????·???¨????????·????????????í?????????§?????????????????????÷?÷???????????????????í???????????÷???ù????"??"????????×è???????????????ó?????????ù??????????????????????±??¤??·?·¨??????±??¤??·??÷±??¤??


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??·?????°????????????÷?÷?????·?????????????????????????????¨????????????????RS485???????¨?????????????÷??±????÷?????÷?÷????????I/O???·?????????÷??????????????????????????×??????????????????????????????·?????????????????????÷?????¨?÷???????¨?¨????1000-2500V?????????????á?????????à±??¤?????ü???ò??·??÷(shunt)???????????ò??????±?×??????????±?????????????????????????????????????á?????????÷????????×????????????à±??¤????????????±??????§??????????????????????????±???????????????

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·??÷±??¤?????¨?????????????????à??±??¤??????±??¤?¨???????????????÷??????TVS????????????·?·¨×??ó???????????????ò??????±????????????????????à??±??¤????????2??????????±??¤???÷???¨??????????·??????????????????????ü???????????????????????????????????ó???÷?????????????????ì???±???????ì????????????????????×è?ò???????ú??????×è?????¨?¨????10 ????????PTC??????????·??????????÷???§?????í??·????????????????????????¨???????????????ì?????????ì??TVS??????????×÷?????ü??????????·??????ó???÷?±???????·?????????????????ó????????·???????????????????°???·??§??????????±??¤???????·?????à±??¤?????????????ó????????·??????????????????¤??????1?×?????è?????????ò??±à?????????????????????????ü????±??¤?§????

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???????·??????????????????×÷±???????3?????????·???????????????????ü????????????±??¤????·????????à?·??????????????????????ר??????RS485???·±??¤???÷??????TED-485??

????±??¤?÷???è???ü???ó???????????????????¤?±??????±???±??¤?÷?¨?????????ü±?±??¤?????????????¤×÷?????????????????ü???·???????¨????????????RS485???????????¨???????¨????6-8V???÷???????????à·??¤?÷??????????????????????????

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PCB?è??????

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