SDCS-CON-2ASDCS-CON-2A

SDCS-CON-2ASDCS-CON-2A

在串行通信中，传输速率常用比特率（每秒传送的二进制位数）来表示，其单位是比特/秒（bit/s）或bps。传输速率是评价通信速度的重要指标。常用的标准传输速率有300、600、1200、2400、4800、9600和19200bps等。不同的串行通信的传输速率差别*，有的只有数百bps，有的可达100Mbps。

    2．单工通信与双工通信

串行通信按信息在设备间的传送方向又分为单工、双工两种方式。

单工通信方式只能沿单一方向发送或接收数据。双工通信方式的信息可沿两个方向传送，每一个站既可以发送数据，也可以接收数据。

双工方式又分为全双工和半双工两种方式。数据的发送和接收分别由两根或两组不同的数据线传送，通信的双方都能在同一时刻接收和发送信息，这种传送方式称为全双工方式；用同一根线或同一组线接收和发送数据，通信的双方在同一时刻只能发送数据或接收数据，这种传送方式称为半双工方式。在PLC通信中常采用半双工和全双工通信。

3．异步通信与同步通信

    在串行通信中，通信的速率与时钟脉冲有关，接收方和发送方的传送速率应相同，但是实际的发送速率与接收速率之间总是有一些微小的差别，如果不采取一定的措施，在连续传送大量的信息时，将会因积累误差造成错位，使接收方收到错误的信息。为了解决这一问题，需要使发送和接收同步。按同步方式的不同，可将串行通信分为异步通信和同步通信。

发送的数据字符由一个起始位、7~8个数据位、l个奇偶校验位（可以没有）和停止位（1位、1.5或2位）组成。通信双方需要对所采用的信息格式和数据的传输速率作相同的约定。接收方检测到停止位和起始位之间的下降沿后，将它作为接收的起始点，在每一位的中点接收信息。由于一个字符中包含的位数不多，即使发送方和接收方的收发频率略有不同，也不会因两台机器之间的时钟周期的误差积累而导致错位。异步通信传送附加的非有效信息较多，它的传输效率较低，一般用于低速通信，PLC一般使用异步通信。

同步通信以字节为单位（一个字节由8位二进制数组成），每次传送l~2个同步字符、若干个数据字节和校验字符。同步字符起联络作用，用它来通知接收方开始接收数据。在同步通信中，发送方和接收方要保持*的同步，这意味着发送方和接收方应使用同一时钟脉冲。在近距离通信时，可以在传输线中设置一根时钟信号线。在远距离通信时，可以在数据流中提取出同步信号，使接收方得到与发送方*相同的接收时钟信号。由于同步通信方式不需要在每个数据字符中加起始位、停止位和奇偶校验位，只需要在数据块（往往很长）之前加一两个同步字符，所以传输效率高，但是对硬件的要求较高，一般用于高速通信。

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PANASONIC AC SERVO DRIVER MADDT1205
 

Vexta Oriental PK569AWM 5 phases stepping motor #1
 

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TOKYO SAWAMURA DENKI?KOGYO DC GEARED MOTOR H11,SS32FJ-GR-36?LOT OF 2 NNB
 

ORIENTAL VEXTA 5-PHASE DRIVER UDK5128NW2
 

KEYENCE POWER &CONTROLLER SJ-B020
 

ORIENTAL MOTOR VEXTA?PK569-NBC 5PH STEPPING MOTOR
 

ORIENTAL MOTOR VEXTA?PK569H-B 5PH STEPPING MOTOR
 

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PL PRO-LOG 7314A-05?RS-232-C SCC CARD.PWB 111742-005
 

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YOSHIDA PSD-50V3
 

OMRON SYSMAC CS1W-NC213 POSITION CONTROL?UNIT
 

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TAKAMURA GEARHEAD REDUCER K6512A
 
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FUJI ELECTRIC FA,AUTO BREAKER EA32AC 5A?NEW LOT OF 3
 

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OMRON SOLID STATE RELAY G3PB-245B-VD NEW?NOT IN BOX LOT OF 2
 

MURR MCS10-230/24 SWITCH MODE POWER SUPPLY
 
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PHOENIX CONTACT POWER SUPPLY QUINT-PS-100-240AC/24DC/10
 

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RELIANCE REMOTE I/O?COMMUNICATIONS MODULE 57C416,57416-S
 

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NEC ISA-BDR BOARD,DTS-4073,TS-483-30201
 
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KOLON INPUT MODULE 1C693MDL645R LOT OF 3, MANUFACTURED UNDER?LICENCE GE FANUC #1
 

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KEYENCE KZ-40T TESTED WORKING
 

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ROCKWELL SAMSUNG PLC?CPL9503 LOT OF THREE
 

VEXTA GEARED STEP MOTOR PMM33B-MG30 0.024 DEGREE PRE STEP
 

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SMC VQ1200-5(2) VQ1100-5(1) VVQ1000-10A-1(9)
 

SMC VQ1200-5(4) VQ1100-5(5) VVQ1000-10A-1(3)
 
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Applied Materials AMAT 0100-09020 REV B?PCB ASSY, FUSE BOARD
 
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ORIENTAL MOTOR SUPER?VEXTA UDK5114N 5-PHASE DRIVER
 

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FUJIKIN DIAPHRAGM VALVE 316L-P LOT OF 3#2
 

TAMAGAWA SEIKI TBL-T?BRUSHLESS DC MOTOR?3275N125E21
 

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MITSUBISHI CC-LINK OUTPUT UNIT MODEL: AJ65SBTB1-32D LOT OF 2
 
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OMRON G3PX-260EUN POWER CONTROLLER
 

YASKAWA AC SERVO MOTOR SGMAH-01AAA21 TESTED WORKING
 

FANUC OUTPUT MODULE?OD64A
 
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FANUC BOARD A20B-0009-0021.02B
 

INTERFACE AZI-4905?BOARD P9607021
 

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MITSUBISHI MELSEC NETII A1SJ71AP21 PLC
 

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ABB DSQC 249A 3HAA3563-AGA/1 BOARD
 

CONTEC COM-4[PCI]H?BOARD
 

CKD CORPORATION VALVE AMDSZ0-3US-1 NEW #1
 

MILLIPORE WG3NS2RR2,?WG3NS1RR2, MOTT CORPORATION POU-05-SV1?LOT OF 11
 

FUJIKIN DIAPHRAGM VALVE 316L 073258 #2
 

RKC INSTRUMENT INC.?TEMPERATURE CONTROLLER REX-F900 F900W801-VV CD-NN5-5N
 
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OPTICAL OBJECTIVE CHANGER BOARD 9978-104-01 REV F
 

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Applied Materials AMAT 0100-09020 REV C?PCB ASSY, FUSE BOARD
 

RKC CB100 FD08-8*AB-5N/A/Y NEW
 

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MULTITEST BAUTEILSEITE BOARD 49.11.18.00
 

OMRON REMOTE TERMINALS G72C-VID16 LINK TERMINALS B7AS-T6B6(2) BROKEN
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#0128 INFICON AG, FL-9496 BALZERS VACUUM?SWITCH VSA100A WITH?3m CABLE
 

OPTICAL FIBER FOR ILLUMINATORS 145cm CONNECTOR DIA. 13.0 &?30.0MM
 

OPTICAL FIBER FOR ILLUMINATORS 165cm HAMAMATSU 030702
 

OPTICAL FIBER FOR ILLUMINATORS 167cm CONNECTOR DIA 13.0mm 17.7mm
 

MINI LINEAR ACTUATOR?MOVING RANGE 30MM?NSK 08HX-0030 W0601MA-3PY-C3Z
 

MITSUBISHI MELSEC PLC AX42 INPUT MODULE
 

ENTEGRIS NT FLOW-THROUGH PRESSURE TRANSDUCER 4210-100G-F08-D00-A-P1-U1 NEW
 

SIEMENS SIMATIC, 6ES5420-4UA13 #1
 
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CONTEC GP-IB[PC]L BOARD
 

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SIEMENS MICROMASTER?6SE6400-0EN00-0AA0
 

METRONIX S40-6-0400ZO ROTARY ENCODER NEW?LOT OF 2
 

METRONIX S40-8-1000VL ROTARY ENCODER NEW?IN BOX
 

HP 54650A HP-IB INTERFACE MODULE
 

SRC VME Systembus SVB-05VME Backplane
 

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INFICON AG, FL-9496?BALZERS VACUUM SWITCH VSA100A
 

FANUC A20B-2002-0680/02A,A350-2002-T686/02 BOARD TESTED WORKING
 
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AB, ALLEN-BRADLEY 24VDC SINK INPUT 1794-0B16 LOT OF 3
 
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FLUOROWARE ES-1C-MD-XX CONTROL MODULE LOT OF 4
 

ASAHI KEIKI ASG-158-17-14 DIGITAL PANEL?METER
 
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TESCOM 100 PXIG MAX.?OUPLET CONN. SIZE:1/4 IN. GAS FLOW:100slpm MAX INLET 600PSI
 

PULSTEC BINARIZER BINA-SW PSB002DD-004-0, BINARIZER BINA- PANEL PSB002DD-003-0
 
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NEC NL6448BC33-53
 

TAMAGAWA TS3653N3E9?STEP MOTOR
 

TAMAGAWA TS3653N2E6?STEP MOTOR
 

NATIONAL PCI-DIO-96?BOARD 182920J-01
 

FANUC BOARD A20B-0009-0031/01A
 

SIEMENS SIMATIC 6ES5470-4UC12
 
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