描述
PLC常用以下几种存储器:
(1)随机存取存储器:(RAM)
用户可以用编程器读出RAM中的内容,也可以将用户程序写入RAM,因此RAM又叫读/写存储器。它是易失性的存储器,将它的电源断开后,储存的信息将会丢失。
RAM的工作速度高,价格低,改写方便。为了在关断PLC外部电源后,保存RAM中的用户程序和某些数据(如计数器的计数值),为RAM配备了一个锂电池。现在有的PLC仍用RAM来储存用户程序。
锂电池可用2~5年,需要更换锂电池时,PLC面板上的“电池电压过低”发光二极管亮,同时有一个内部标志位变为l状态,可以用它的常开触点来接通控制屏面板上的指示灯或声光报警器,通知用户及时更换锂电池。
(2)只读存储器(ROM)
ROM的内容只能读出,不能写入。它是非易失的,它的电源消失后,仍能保存储存的内容。ROM—般用来存放PLC的系统程序。
(3)可电擦除的EPROM(EEPROM或E2PROM)
它是非易失性的,但是可以用编程器对它编程,兼有ROM的非易失性和RAM的随机存取优点。但是写入信息所需的时间比RAM长得多,EEPROM用来存放用户程序。有的PLC将EEPROM作为基本配置,有的PLC将EEPROM作为可选件。
欧美品牌停产的,常用的“PLC”备品备件
我司产品应用于以下领域:
1,《发电厂DCS监控系统》
2,《智能平钢化炉系统制造》
3,《PLC可编程输送控制系统》
4,《DCS集散控制系统》
5,《智能型消防供水控制系统》
6,《化工厂药液恒流量计算机控制系统》
7,《电气控制系统》造纸,印染生产线,变电站综合自动化控制系列
本特利,英维思,伍德沃德,福克斯波罗、西屋、瑞恩、施耐德莫迪康、ABB、AB、西门子、摩托罗拉、GE发那科、安川、博世力士乐,ACSO,力士乐等各大品牌的DCS系统配件,机器人系统配件,大型伺服系统备件。
QTY 10 NEW GM/SATURN OEM 21000938 4cyl 1.9L AIR FILTERS
GLANCE HC RTD COMMERCIAL GLASS CLEANER 40:1 CONCENTRATE
NEW CASE OF 2 RTD BOTTLES,MAKES 32 GALLONS…CHEAP!!
NEW CASE OF 4,900 DIGI SM90 SCALE LABELS
NEW EVERPURE T7O-BW TASTE&ODOR WATER FILTER CARTRIDGE
FERRAZ PROTISTOR 700V 400A FUSE A 070 URD 32 TTI 0400C
QTY 2 NEW EMERSON RPT25A4 25PR TERMINAL BLOCKS F002685
NEW OEM 2005 FORD THUNDERBIRD CLIMATE CONTROL AC/HEATER
DATACARD DURAGARD CLEAR LAMINATE 565750-001 CP80/CP80+
QTY 36 NEW SELMER 2929 CORK GREASE CLARINET SAXAPHONE
NEW OMC STAINLESS STEEL FLANGE SA/A182F304/F30?4L B16
12 NEW CARLISLE 5 x 24 WASHABLE COTTON DUST MOP HEADS
12 NEW COGNITIVE BLASTER ADVANTAGE LX DLX RIBBONS
BRAND NEW CASE,4.25 x 3156(263′)P/N 04-00-0028-07
60 PHILIPS E10/E12 2.25V KRYPTON PEN-LIGHT BULBS/LAMPS
40 ELKHART KLEENFIT 1/2 COPPER GAS LINE ELBOW FITTING
NEW GENUINE LUCIDIOM 92350 BLACK IMAGE DRUM FOR EQ-9800
GENUINE LUCIDIOM 92353 YELLOW IMAGE DRUM FOR EQ-9800
NEW HP/COMPAQ BLC7000 407295-001 ON-BOARD ADMIN SLEEVE
NEW CHEVY/GMC COLORADO/CANYON OEM VORTEC 2900 RESONATOR
ALSTOM RED LED AIRFIELD/RUNWAY/TAXI/RR SIGNAL?LIGHTS
NEW SECURITRON PB3 PUSH TO EXIT BUTTON CONTROL ASSEMBLY
CASE GOJO PRO 5000 ANTIBACTERIAL HAND SOAP REFILLS 2x5L
NEW VALCOM V-9939B MICROHONE ADAPTER UNIT
NEW COOPER WHEELOCK ET70WP WEATHERPROOF STROBE SPEAKER
QTY 5 LEBLANC FRENCH HORN SNAKE BRUSH W/8 VALVE/KEY OIL
NEW HONEYWELL M6410A1029 Cartridge Globe Valve Actuator
500’INTERNAL APPLIANCE WIRE 14AWG 600V SOLID COPPER
QTY 25 ZURN QQ800X 1 FEMALE SWEAT BARB BRASS FITTINGS
NEW CASE 6 CARLISLE 2.7 QT FOOD STORAGE CROCKS W/LIDS
GERBER 41-812 CHROME TRIP LEVER BATHTUB DRAIN KIT
2006/2007 TOYOTA HIGHLANDER HYBRID ENGINE BLOCK HEATER
QTY 4 NEW FINISHPRO 14 DRYWALL HAMMERS HICKORY HANDLE
CASE GOJO MICRELL ANTIBACTERIAL HAND SOAP REFILLS 4x 2L
CASE-3 GOJO FMX-12 LUXURY FOAM HAIR&BODY WASH 5163-03
QTY 6 NEW INDUSTRIAL PACKING/STRAPPI?NG TAPE DISPENSERS
10 GE BIAX T/E ECO 32W 4-PIN FLUORESCENT BULBS GX24Q-3
50 NEW SOUTHCO AdvancedMC MODULE HANDLES P7-M-812-000
12 COGNITIVE BARCODE BLASTER/ADVANTAGE LX WAX RIBBONS
BRAND NEW CASE,4.23 x 3156(263′)P/N 04-00-0028-01
Enlarge
10 ROLLS AIRTECH VACUUM BAGGING SEALING TAPE 1/2 x 25′
48 BEIGE CARLISLE 9oz INSULATED BOWLS DESSERT/DIP/SAL?SA
4 NEW SILITE LARGE CANOE SERVING/DECORAT?IVE BOWLS BLACK
5 NEW KIDDE 500°STANDARD RESPONSE THERMO-BULB LINKS
5 NEW KIDDE 360°STANDARD RESPONSE THERMO-BULB LINKS
12 NEW ACDELCO PF2/5575840 DURAGUARD OIL FILTERS
NEW NAPA 39571 MASTER CYLINDER CHEVY/GMC TRUCK 1983-95
25 AMERICAN EXPRESS CHECK PRESENTERS/CRED?IT CARD HOLDER
NEW 500’GENESIS 22/4 ALARM/ELECTRONI?C/SPEAKER CABLE
25 NEW RESTAURANT CHECK PRESENTERS/CREDIT CARD HOLDERS
VCS1-171-1 DC/DC CONVERTER BOARD COOPER POWER SYSTEMS
CORNING LC/PC-LC/PC FIBER OPTIC CABLE 30M DUPLEX 50/125
6 NEW CARLISLE 10LB MARBLE OCTAGONAL SERVING CROCKS
JENSEN DWR52 REMOTE W/LED SCREEN DV352 MARINE STEREO
500’NEW CCI COLEMAN 16 GAUGE COPPER FIXTURE WIRE/CABLE
NEW WHELEN SIREN MOUNT FOR 2003 CROWN VICTORIA SABKT17
28,000 GENUINE MONARCH 1136 RED PRICE GUN LABELS W/INK
QTY 10 NEW OEM FORD 50 AMP RELAY P6STD 5C3T-14B192-AA
MASCOT 9940 3-STEP LEAD ACID BATTERY CHARGER 14.7V 2.3A
12 NEW COGNITIVE BLASTER ADVANTAGE RIBBONS FOR BT242003
BRAND NEW CASE,2.4 x 3156(263′)P/N 04-00-0031-02
Enlarge
2 PAIRS YAKIMA Q125 AND Q126 CLIPS FOR Q TOWER SYSTEM
ORDER Q125 AND Q126 OR MIX AND MATCH
50 Zurn QQ650X 1/2 Male Sweat x 1/2 Barb BRASS FITTINGS
MAYTAG OEM 6-2095720/22204?012 WASHER STEM BOOT SEAL KIT
NEW IBM 6275529 GREEN PRINTBAND DOT MATRIX 4234 PRINTER
NEW HI-TECH SMART SYSTEMS PST5000 HOTEL THERMOSTAT
NEW KEYSCAN TX4PRX 4-BUTTON TRANSMITTER/KEY FOB KEYFOB
QTY 2)52oz CARTONS GOLD MEDAL COTTON CANDY FLOSSUGAR
QTY 2)52oz CARTONS GOLD MEDAL COTTON CANDY FLOSSUGAR
6 NEW CARLISLE 5LB MARBLE OCTAGONAL SERVING CROCKS
OEM TF950/29539579 ALLISON DIESEL TRANSMISSION FILTER
NEW ACDELCO GF851 FUEL FILTER DODGE CARAVAN++++
COMTEC INSWING LATCH KIT FOR COMMERCIAL BATHROOM DOOR
COMTEC OUTSWING LATCH KIT FOR COMMERCIAL BATHROOM DOOR