RS422-485简介.ppt [兼容模式]

1 RS422/485 RS422/485 RS422/485 RS422/485 RS422/485/232 RS422/485/232 RS422/485 EMI RS422/485 RS422/485 RS422/485 RS 422 EIA RS 422 A Standard Apple Macintosh RS 422 RS 232 RS 232 RS 485 EIA 485 RS 422 10 32 10 32 RS 485 RS 422 RS 422 RS 485 RS 485 4000 1200m RS485 RS485 4000 1200m RS 422/485 RS422/485 TTLTTLRS - 232 CTTLTTLRS - 423A+ RS-422A TTLTTLRS 422A+ RS485 A B RS485 A B A B +2 +6V 2 6V C RS 485 RS422 RS422 RS422/485 RS422/485 AA AA BB if A B 200mV.

2 TTL 1 if A B 200mV, TTL 0 200mV 6V RS422 DB9 RS422 DB9 1 GND 2 TXA TX A2 TXA TX A3 RXA RX Y456 TXB TX B7 RXB RX Z89+9V 9+9V OK RS422 RS422 RS422 ABYZ RS422 A B Y Z 10 RS422 4K 10 4K 100 RS422 RS422 10Mb/s 100 1Mb/s 1200 /400 100kb/s 10 10

3 < 300m 100 RS485 RS485 RS422 A B A B A B RS485 RS422 RS485 RS422 1200mABABRTRtRt120 120 RABT 100 AB ABAT BR AARAB 100 T100 AB RS485 RS485 10Mb/s 100 1Mb/s 1200 /400 100kb/s 32 12K 32 12K < 300m 120 RS422/485/232 RS422/485/232 RS232RS422RS485 1 1 1 10 1 32 15 1200 1200 200kb/s10Mb/s10Mb/s +/ 25V 6V 7V 12V +/ 5V +/ 15V+/ 20V+/ 15V +/ 5V+/ 15V+ + +/ 25V+/ 6V+/ 6 VRS422/485/232 RS422/485/232 RS232RS422RS485 ( )3K 7K10054/120 ( )30V/ sN/A N/A +/ 15V 10V +10V 7V +12V +/ 3V+/ 200mV+/ 200mV 3K 7K4K( )

4 12K N/A3V +3V1V +3V N/A 3V +3V 1V +3V N/A 7V +7V 7V +12 VRS422/485 RS422/485 RS422 10 RS485 32 RS 422 10 RS 485 32 1 2 3 RS422/485 / a b c d e f a b c RS422/485 / RS422 RS485 RS-422 RS-485 MAXIM 3 RS-485 MAX483 250ns

5 24 AWG PVC 250kb/ 16 MAX483 250kb/s 16 MAX483 RS-485 RS422/485 / S422 RS-422 RS-485 RS-422 100 RS-485 120 100 120 RS422/485 / RC C C RS422/485 / RS422/485 / S422/48 RS422/485 RJ45 RS485 >32 1200m RS485.

6 485 RS422/485 / RS-422 RS-485 RS422 RS485 A B 1 RS422 RS485 1 RS-422 RS-485 RS-422 -7 +7V RS-485 -7 +12V RS422/485 / Vcm Vos Vgpd Vcm Vos Vgpd Vos 3V Vgpd Vcm RS422 Vcm 7V 7V RS485 Vcm 7V 12V RS422/485 EMI/ 2 EMI RS-422 RS-485 RS-422 RS-485 VGPD VGPD

7 RS422/485 EMI/ 1 2 2 RS422/485 EMI/ 3 3 RS422/485 / RS422/485 200mV S/85 00 A B +200mV AB -200 +200mV 0V 0V 200mV RS422/485 / -200mV A B 5V 1k RS422/485 /

8 RS-422 RS-485 RS422/485 / 1 1 MAX458E MAX487E MAX1487E SN75 LBC184 2 IC Maxim MAX1480/MAX1490 2500V Maxim MAX1480/MAX1490 2500V RS422/485 / 3 TVS MOV 3 TVS MOV

9 RS422/485 RS422/485 A A B B 5V