MVI56-MNETR  MVI56-MNETR  

4. 基帶傳輸與頻帶傳輸

基帶傳輸是按照數(shù)字信號(hào)原有的波形（以脈沖形式）在信道上直接傳輸，它要求信道具有較寬的通頻帶。基帶傳輸不需要調(diào)制解調(diào)，設(shè)備花費(fèi)少，適用于較小范圍的數(shù)據(jù)傳輸。基帶傳輸時(shí)，通常對(duì)數(shù)字信號(hào)進(jìn)行一定的編碼，常用數(shù)據(jù)編碼方法有非歸零碼NRZ、曼徹斯特編碼和差動(dòng)曼徹斯特編碼等。后兩種編碼不含直流分量、包含時(shí)鐘脈沖、便于雙方自同步，所以應(yīng)用廣泛。

頻帶傳輸是一種采用調(diào)制解調(diào)技術(shù)的傳輸形式。發(fā)送端采用調(diào)制手段，對(duì)數(shù)字信號(hào)進(jìn)行某種變換，將代表數(shù)據(jù)的二進(jìn)制“1”和“0”，變換成具有一定頻帶范圍的模擬信號(hào)，以適應(yīng)在模擬信道上傳輸；接收端通過(guò)解調(diào)手段進(jìn)行相反變換，把模擬的調(diào)制信號(hào)復(fù)原為“1”或“0”。常用的調(diào)制方法有頻率調(diào)制、振幅調(diào)制和相位調(diào)制。具有調(diào)制、解調(diào)功能的裝置稱(chēng)為調(diào)制解調(diào)器，即Modem。頻帶傳輸較復(fù)雜，傳送距離較遠(yuǎn)，若通過(guò)市話系統(tǒng)配備Modem，則傳送距離可不受限制。

PLC通信中，基帶傳輸和頻帶傳輸兩種傳輸形式都有采用，但多采用基帶傳輸。
我們?cè)谠O(shè)計(jì)小型的PLC控制系統(tǒng)時(shí)，常常會(huì)需要在外部改變PLC內(nèi)部的數(shù)據(jù)，譬如Counter, Timer或者Data的值，以適應(yīng)生產(chǎn)過(guò)程的需要。而且要求系統(tǒng)關(guān)機(jī)以后，這些數(shù)據(jù)還能夠保存在PLC內(nèi)部，當(dāng)下次開(kāi)機(jī)后，這些數(shù)據(jù)可以被調(diào)出繼續(xù)使用。

        現(xiàn)在許多小型的PLC都或多或少地提供了掉電保持寄存器，以便在PLC斷電的時(shí)候，保存用戶(hù)想要保存的數(shù)據(jù)。但大多數(shù)時(shí)候，PLC制造廠商為了節(jié)約成本，不可能提供足夠數(shù)的掉電保持寄存器供系統(tǒng)設(shè)計(jì)人員使用，所以當(dāng)被調(diào)整的數(shù)據(jù)項(xiàng)目超過(guò)PLC內(nèi)部的掉電保持寄存器的數(shù)目的時(shí)候，我們不得不減少被調(diào)整的數(shù)據(jù)項(xiàng)目（固定或不用）或者購(gòu)買(mǎi)具有更多掉電保持寄存器數(shù)目的PLC，這樣的話，就使得生產(chǎn)機(jī)械缺乏靈活性和適應(yīng)性，從而降低產(chǎn)品檔次或增加成本。

        下面就介紹解決這種問(wèn)題的一種方法，以便大家設(shè)計(jì)時(shí)參考。

    所用PLC：松下FP0－C16T，被調(diào)整數(shù)據(jù)有16個(gè)，PLC內(nèi)部掉電保持寄存器數(shù)目為10個(gè)，其中8個(gè)數(shù)據(jù)寄存器（DT1652－DT1659：8個(gè)各16Bit）和2個(gè)字的內(nèi)部繼電器（WR61、WR62：2個(gè)各16Bit）。如果按常規(guī)的一個(gè)被調(diào)整數(shù)據(jù)占用一個(gè)數(shù)據(jù)寄存器的方法，這顯然不能調(diào)整16個(gè)被調(diào)整數(shù)據(jù)，而只能調(diào)整10個(gè)被調(diào)整數(shù)據(jù)。為此，本人專(zhuān)門(mén)分析了16個(gè)被調(diào)整數(shù)據(jù)的數(shù)據(jù)調(diào)整范圍，發(fā)現(xiàn)多數(shù)數(shù)據(jù)的調(diào)整范圍只需要從0～255，即0～28-1；而掉電保持?jǐn)?shù)據(jù)寄存器DT1652等內(nèi)部的數(shù)據(jù)大小為216-1，即256×256-1；所以我們可以將一個(gè)被調(diào)整的數(shù)據(jù)只用到數(shù)據(jù)寄存器的低8位，那么該數(shù)據(jù)寄存器的高8位就可以來(lái)存儲(chǔ)另一個(gè)被調(diào)整數(shù)據(jù)。

PRECISION RIGHT ANGLE REDUCER RATIO 20:1?KEG2B20L GOOD FOR 4TH AXIS
 
PRECISION RIGHT ANGLE REDUCER RATIO 20:1?KEG2P20R GOOD FOR 4TH AXIS
 

PRECISION RIGHT ANGLE REDUCER RATIO 20:1?KEJ2-20RB GOOD FOR?4TH AXIS
 

RIGAKU SHAFT EXTENSION
 

VEXTA 2-PHASE STEPPING MOTOR C7461-9212KEM DC 24V MAGNETIC?BRAKE 200P ENCODER
 

OMRON G9SX-NSA222-T03 AND G9SX-BC202
 

MYCOM MNC-100 TESTED?WORKING
 

PREMIUM SYSTEM PAV25-D9-0023
 

MDC KAV-100-P PNEUMATIC BELLOWS VALVE?00-37462 311073
 

OMRON E5CN-Q2H03TC-FLK LOT OF 3 WITH INSTALLATION BRACKET
 

MERLIN GERIN MULTI 9?C60N D32 CI LOW?VOLTAGE TVSS DS150E-120 4EA
 

PILZ PLC MODULE - PSS DI 2 EINGABE BIS KAT. 4mit Taktung NO?FRONT COVER
 

PILZ PLC MODULE - PSS DO S 32 DIGITAL OUTPUTS NO FRONT COVER
 

TOSHIBA PPLC MODULE?TYPE TDA364**S DA364
 

USED NTN BEARING 6919
 

SANYO DENKI DRIVER PENTASYN PMM-BA-5603-1
 

ADVANTECH PCA-6106P3-0C1 REV:C1 SBC BACKPLANE
 

#0008 ADAPTRONIC KT920 TEST EQUIPMENT SUB COMPONENT, MODULE?24V _ 5V
 

#0010 KT920 TEST EQUIPMENT SUB COMPONENT, POWER SUPPLY MEAN?WELL SP-500-48
 

#0059 YASKAWA AC SERVO MOTOR SGMAS-A5ACA21 TESTED WORKING
 

#0068 PULS POWER SUPPLY SL10.300 INPUT 3?PHASE 400-500V OUTPUT 24-28V 240W
 

#0089 MECMESIN TORQUE GAGE OPERATING PANEL
 

#0094 TESCOM REGULATOR PSIG MAX 100 OUTLET WITH PC-601A-VR PRESSURE SENSOR
 

#0095 TESCOM REGULATOR PSIG MAX 150 OUTLET WITH PC-302A-VR PRESSURE SENSOR
 

#0096 TESCOM REGULATOR PSIG MAX 150 OUTLET WITH PC-302A-VR PRESSURE SENSOR
 
#0131 FUJIKIN DIAPHRAGM VALVE 038818 LOT?OF 5
 
#0132 TESCOM 100 PSIG MAX WITH DATA INSTRUMENTS CRITICAL FLUIDS S14VSV100CP
 

#0135 TESCOM REGULATOR 100 PSIG MAX ROUND KNOB WITH TEM TECH?LAB HYPSMV-WD420
 

#0136 TESCOM REGULATOR 100 PSIG MAX BLACK KNOB WITH TEM TECH?LAB HYPSMV-WD420
 

#0137 TESCOM REGULATOR 100 PSIG MAX WHITE KNOB WITH TEM TECH?LAB HYPSMV-WD420
 
#0138 TESCOM REGULATOR 60 PSIG MAX OUTLET WITH TEM TECH SKPSMV-WD420
 

ALLEN-BRADLEY BULLETIN 700 TYPE P 700-P800A1 B DIRECT DRIVE?CASE DAMAGED
 

SPACESOLUTION ANGLE?VALVE
 

VEXTA OPERATIONAL UNIT OP200A LOT OF 2
 

MORITEX FIBER OPTIC?CABLES FOR ILLUMINATORS 222cm END DIA 15.0mm T CONNECTOR
 

SIEMENS SIMATIC PLC?MODULES REMOTE BASE?CONTROLLER 505-6851A
 

FUJI ELECTRIC T-LIMK, FTT3204-G02 (NH6X32)
 

MITSUBISHI PROGRAMMABLE CONTTROLLER FX1S-14MR-ES/UL LOT OF 2
 
PARKER SERVO MOTOR CM232BE-115817
 

MITSUBISHI MELSEC INPUT/OUTPUT UNIT AJ35TC1-32DT PLC #1
 
MITSUBISHI MELSEC OUTPUT UNIT AJ65BTB1-16D PLC
 

MITSUBISHI AC SERVO?MOTOR HC-KFS053B 50W?TESTED,WORKING
 
WEST ELECTRONICS DD115-0504CTM TEMPERATURE CONTROLLER
 
FANUC A16B-2200-0490/07D BOARD
 

CKD CORPORATION VALVE AMDSZ0-3US-1 NEW
 

ROTEC VTEMP CONTROLLER VTEMP-PCB1,VTEMP-PCB2 AND VTEMP-PCB3
 

CONDER POWER SUPPLY?HB5-3/OVP-A+,100-42004 M-0288*HB5-3-OV-A+
 

SMC HIGH VACUUM VALVE XLC-25H0
OMRON POWER SUPPLY S82K-05024, S82K-0124, S82K-00305
 
COMIZOA COMI-LXT5Y V5.10 BOARD NNB
 

OMRON LINK TERMINALS?B7AM-8B31
 

VEXTA STEPPING MOTOR?5-PHASE PH569-A
 

YASKAWA SERVOPACK MECHATROLINK I/F UNIT?JUSP-NS100 WORKING
 

YASKAWA SERVOPACK DRIVER SGDA-01AP TESTED WORKING
 

KEYENCE PRESSURE SENSOR AP-40 NEW
 

SAMSUNG DC BRUSHLESS MOTOR CSM-01BB1ANT3
 

RELIANCE 57C421B PULSE TACH INPUT MODULE?57421-3
 

GE FANUC SERIES 90-30, IC693PWR321S POWER SUPPLY WORKING
 

JEOUNG IL JPD-1100 BOARD
 
MITSUBISHI MELSEC INPUT UNIT AJ35TB1-16DPLC #1
 

FUJI ELECTRIC EG53F?40A NEW
 

OMRON DIGITAL COUNTER H7A-4D
 

M SYSTEM CO.,LTD, MODEL: R7C-TS4-R POWER: 24V DC
 

FUJI ELECTRIC EA53B?40A AUTO BREAKER NEW
 

HONEYWELL SENSING&CONTROL CIRCUIT PROTECTOR GCP-33A 10A AX I?LOT OF 3 NEW
 

AITEC ROBOT CONTROLLER POWER SUPPLY BOARD PWB-653C 94V-0,CEM-3 DENSEI-LAMBDA
 

APPLIED MATERIALS AI?MUX/CURRENT SENSE ASSY. 0100-09011 REV:G BOARD
 

SMC VQ1200-5(4) VQ1100-5(5) VVQ1000-10A-1(3)
 

ASTEC POWER SUPPLY LPQ154
 

Schneider Contactor?LC1D50M7 LOT OF 2 NEW
 
MULTITEST BAUTEILSEITE AMIO CENTRAL CARD?49.03.22.09
 

AVAL DATA BOARD AVME-311F
 

KLA TENCOR 655 730728 I0
 

KLA TENCOR 655 656233 00 REV A1
 

OMRON 3G8B2-IP000 BOARD,0228482-5A
 

MOELLER CONTACTOR 40E DIL ER-40-G LOT OF?3
 

MOELLER CONTACTOR DIL00M, DIL00M-10, 20?DIL
 

MOELLER CONTACTOR 40E DIL ER-40 LOT OF 3
 

KITZ SCT DIAPHRAGM VALVE PCTFE-SEAT SCV?S20Y 316L 10K-1/4" EP SD LOT OF 2
 

BENKAN SCV PCTFE-SEAT 316L 10K-1/4" EP LD LOT OF 2
 

HP HEWLETT PACKARD 10780C RECEIVER, 10780B RECEIVER
 

PANASONIC AC SERVO DRIVER MSD013P1E
 

SAMSUNG DC BRUSHLESS MOTOR CSM-A5BB1ANT3
 
PC248H BOARD
 

OMRON PLC C200H-ID217 LOT OF THREE!
 

SEOUL SEMICON PRECISION P8255 BOARD
 

SMC MSQB10A ROTARY ACTUATOR
 

SAFETY LIGHT CURTAIN?RJ-V22R PJ-V20R PJ-V22T PJ-V20T
 

VEXTA 5PHASE DRIVER?CSD5814VN
 

RKC INSTRUMENT TEMPERATURE CONTROLLER F300FD12-V AB-NN5-5N
 

RKC INSTRUMENT F900FD12-V AB-NN5-5N TEMPERATURE CONTROLLER WORKING
 
RKC INSTRUMENT F900W801-VV CD-NN5-5N Z-156B
 
FESTO DZH-32-40-PPV-P 14042 WITH POSITION SENSORS
 

PRECISION RIGHT ANGLE REDUCER RATIO 20:1?KEG2P20R FLANGE DENT GOOD FOR 4TH AXIS
 

NANOMOTION AB1A-HR4-1-S
 

NMB CAD-819C DIGITAL?PEAK HOLDER
YAMATAKE DISTRIBUTED?I/O MODULE HD-CSIM00M
 

YAMATAKE DISTRIBUTED?I/O MODULE HD-CDIM00
 

SANYO DENKI 103-4507-7011 5-PHASE STEPPING MOTOR,HEDS-5600?A14 ENCODER LOT OF 5
 

CAPACITANCE DIAPHRAGM GAUGE MFG UNDER PATENT CMOH-01-160S123
 

CAPACITANCE DIAPHRAGM GAUGE MFG UNDER PATENT CMOHL0115006
 

CAPACITANCE DIAPHRAGM GAUGE MFG UNDER PATENT CMLHL1115006
 

ORIENTAL MOTOR CO.LTD BRAKE REVERSE PACK?SBMR502 LOT OF 2
 

ORIENTAL MOTOR CO.LTD BRAKE REVERSE PACK?SBR502 LOT OF 2
 

ORIENTAL MOTOR CO.LTD SPEED CONTROLLER?DSP502M LOT OF 2
 

MITSUBISHI CC-LINK OUTPUT UNIT MODEL: AJ65SBTB1-16T
 

FUJIKIN INCORPORATED?VALVE 316 30K→ 3/8?LOT OF 2
 

ESC AIO-4ESC REV 1.0?BOARD
 

MOTOROLA MVME,VME 761-001 PCB BOARD #1
 
OMRON C200HW-PD024?POWER SUPPLY UNIT LOT OF 2 DC 24V 50W TESTED WORKING
 

AUTONICS PULSE METER?MP5W-4N
 

FUJI ELECTRIC AUTO?BREAKER EA33 15A LOT?OF 2
 

OMRON TEMPERATURE CONTROLLER E5EN-C3O3TC-FLK
 

KEYENCE KZ-R16X
 

KEYENCE KZ-R16R
 

TOKYO BOARD AI MODULE #2 3M81-023124-13
 

TOKYO BOARD AI MODULE #2 3M81-023124-12
 

UNI-POLAR STEP MOTOR?DRIVER HMD-20U,HMD-20U-3A LOT OF 2 NNB
 

ORIENTAL MOTOR SUPER?VEXTA 5-PHASE DRIVER UDK5114N
 

OMRON PLC C2000H-AD001 A/D UNIT
 

ALLEN-BRADLEY MODEL:?1771-OAD/B 12 TO 120V AC OUTPUT MODULE?LOT OF 2
 

ALLEN-BRADLEY MODEL:?1771-IBD/B INPUT MODULE 10-30VDC LOT OF?3
 

TESCOM 100 PXIG MAX.?OUPLET CONN. SIZE:1/4 IN. GAS FLOW:140slpm MAX INLET 600PSI
 

TESCOM 60 PXIG MAX.?OUPLET ELK RIVER, MN USA MAX INLET 600?PSI 64-2641KRT21
 

TESCOM 100 PXIG MAX. OUPLET ELK RIVER,?MN USA MAX INLET 600?PSI 64-2662KRM21
 

TESCOM .41 MPa/60 PSIG PXIG MAX. OUPLEK RIVER, MN USA INLET 150 PSI LOT OF 3
 
ADVANTECH PCI-1756 REV. A1 01-3 BOARD
 

VEXTA STEPPING MOTOR?5-PHASE A4318-9215TG
 

PCI-7296,0060 GP,51-12009-0A5O BOARD
 

VEXTA ORIENTAL 5-PHASE STEPPING MOTOR PK566-NBC
 

Panasonic KS152 Camera Control Unit GP-KS152MD
 

MITSUBISHI AC SERVO?DRIVE MR-C40A
 

THK BEARING RB7013UUC0 NNB
 

SUPER VEXTA UDK5114N-M 5-PHASE DRIVER #1
 

PANASONIC AC SERVO MOTOR MSM012A1A MATSUSHITA
 

BROOKS AUTOMATION TLG-RS23 TRANSPONDER READER, TLG-I1-100-S0-00EB W/ ROD ANTENNA
 

XYCOM VMEBUS BOAED XVME-202,70202-001 L
 

C104H/PCI [2PCS] C168H/PCI [1PCS] BOARD?LOT OF 3
 

NTN UCHP205 BEABING?NEW
 
NATIONAL PCI-DIO-96?BOARD 182920K-01
 

IAI SEL NT I/O BOARD?R47678B
 

IAI SEL NT I/O 2 RT-A BOARD
 

IAI SEL NT I/O BOARD?R46823B
 

BROOKS TLG-RS232,TRANSPONDER READER ASC-I1 TLG-I1-1000-S0-00EB
SMC CYLINDER CDQ2B20D-J9742-50 LOT OF 2?NEW
 

SMC CYLINDER CQSB25-15D LOT OF 3 NEW
 

OMRON J7AN-E3 CONTECTOR LOT OF 3
 
OMRON S8VS-24024 POWER SUPPLY
 

RKC REX-F400 Temperature Controller
 

ORIENTAL MOTOR SPEED?CONTROLLER MSP101 LOT OF 2
 

ORIENTAL MOTOR SUPER?VEXTA 2-PHASE DRIVER UD2115B UD2115B-G3
 

ALLEN-BRADLEY PLC FLEX I/O 1794-ADN,1794-1B16
 

OMRON POWER SUPPLY S82J-10024D LOT OF 2
 

NEMIC-LAMBDA POWER SUPPLY BOARD RWS150A-24
 

Adtron SolidState Data Drive ISA Adapters SDD-B-ISA SDD-I-ISA BOARD
 

ORIENTAL MOTOR SPEED?CONTROLLER MSP301N?LOT OF 2
 

STAINLESS STEEL BELLOWS FOR VACUUM LINE.?FLANGE TYPE OD.40mm?ID26mm.L220-240mm
 

ATI TECHNOLOGIES INC. PN 109-57400-31 BOARD
 
MOELLER CIRCUIT BREAKER FAZ-2-C1, FAZ-2-C4(2) LOT OF 3
 

VERIFLO DIVISION VALVE MODEL: SQMICRO502PBENKAN
 
TESCOM 100 PXIG MAX. OUPLET ELK RIVER,?MN USA MAX INLET 600?PSI 1/4 IN. 140SLPM
 

OMRON TEMPERATURE CONTROLLER E5CS-RKJ
 

ADVANTECH PCI-1756 REV. A1 01-2 BOARD #2
 

VEXTA STEPPING MOTOR?2-PHASE PK268-01A
 

HANYOUNG TEMPERATURE?CONTROLLER DX3-PSWNR 24VDC
 

SHINDENGEN POWER SUPPLY HY05005GN
 

VEXTA STEPPING MOTOR?5-PHASE PK566H-A
 

VEXTA STEPPING MOTOR?2-PHASE PK268-03A
 

YASKAWA SERVOPACK DRIVER SGDM-A5BDA
 

TF LCD MODULE APEX?RG128646-1 YFHDYB-TF70-01 NOT IN BOX. LOT OF 5.
 

NUDAQ PCI-7250 REV A3 BOARD
 

GE FANUC 24VDC 32PT?POS/NEG FAST INPUT MODULE IC693MDL655E WORKING
 

FUJI VME IS70B SERVO?BOARD DF9200143-BO,JZMMC-IS70B
 

SIEMENS SIMATIC S5 6ES5-931-8MD11
 

MITSUBISHI MELSEC INPUT UNIT AX41C PLC
 

FUJI ELECTRIC FA,AUTO BREAKER EA33AC 30A?NEW LOT OF 2
 

TEM TECH LAB. MODEL?NPS4200AL RANGE: 0~5kgf/ cm2 LOT OF 2
 

SDTC FLOW MONITOR 2001M LOT OF 2
 

YAMATAKE HONEYWELL SDC21
 

SIEMENS REMOTE BASE?CONTROLLER 505-6851A,PWB2586356-0003 REV.G BOARD
 

FUJIKIN INCORPORATED?O.P 4~6kgfcm2G,TYPE-NO, 316L-P
 

MOELLER FAZN-C50-2 LOT OF 4
 

HONEYWELL SENSING&CONTROL CIRCUIT PROTECTOR GCP-33A 10A AX M?LOT OF 2 NEW
 

HONEYWELL SENSING&CONTROL CIRCUIT PROTECTOR GCP-33A 30A AX I?LOT OF 2 NEW
 

HONEYWELL SENSING&CONTROL CIRCUIT PROTECTOR GCP-31A 30A AX I?LOT OF 3 NEW
 

HONEYWELL SENSING&CONTROL CIRCUIT PROTECTOR GCP-31A 0.1A AX?I LOT OF 3 NEW
 

WEIDMULLER CONNECTPOWER 8708670000,CP SNT 120W 24V 5A POWER?SUPPLY
 

WSAC SYSTEMS SI9711M?BOARD
 

AITEC ROBOT CONTROLLER BOARD AI-IF-3
 

I-BUS SYSTEMS 12 SLOT BACKPLANE BOARD 103-00030-01,100955
 

OMRON TEMPERATURE CONTROLLER E5EX-A
 

RKC INSTRUMENT INC.?TEMPERATURE CONTROLLER REX-F400 F400AK09-M NN-NNN-5N