ABBEI803F(3BDH000017R1)PLC是一种监控装置,为了监视及控制各项机电等设备,当然必须与那些设备有相互沟通的方式.在这些机电设备的世界里,人类发明了各种形式的讯号,以作为它们之间的沟通媒介.目前来说,人们研发出来的各种侦测如:温度,湿度,压力等自然现象的侦测元件,都是将所测得的数据转换为线性对应的电流信号,通常是4~C接受这样的信号,就可依据电流的大小而知道侦测器侦得的目前状况.Pulse(脉冲)信号是一种形式的接点信号.它的意思是每"达到条件"时,接点会闭合一次.例如:某个转轮式的流量计,可能被设计成--当它计算出水流累计量达到一度时,就将输出接点闭合一次.至于所谓的RS232讯号,乃是指一种"通讯"的方式(RS232是一种电气规格).以上所提的各种信号都是电气形式的讯号.而且每个信号都需要***的线路来作传递.通讯的方式,则可以把它当作设备用"交谈"的方式来做沟通.它们彼此间以一串行的数值信号来组成所要传递的资料,使得多样化的资料能够借由一组通讯线路来达成.4~20mA算是通用规格.另外常见的还有0~20mA.另外还有电压式的:0~5V,1~5V,0~10V,等等.当然还有以其他形式来表达自然环境中各种"连续性"数值的方式,像是:电阻式,以及其他变化应用.总之呢,4~20mA的规格***多.但是,事实上,4~20mA的电流信号,在进入电路板时,还是会串上一个250或500欧姆的电阻,而获得一个1~5V或2~10V的电压,然后再由A/D(类比/数位)转换IC得到一个对应的数值.这个"5V"或"10V"的原因,乃是人们研发出来的A/DIC***容易且廉价的关系而已.至于为何以电流的方式较多,因为4~20mA控制电流不易因传送距离较长而导致讯号衰减。MAC57C-12-522BABAVALVE*USED*EBMPAPST4580Z*NEWOUTOFBOX*GEMTMPLUS-120*USED*WATTSU5B*USED*LOTOF2LEVITON165-00ML3-00P*NEWINFACTORYBAG*NORGRENK41EA00-KS6KV2*USED*HAYSSEN810A-0100-00AB*USED*ALLENBRADLEY1784-KTSERIESB*USED*SOLONPRESSURESWITCH2PSW1D2*USED*MILBANK12126-HC1*USED*BROOKSFLOWMETER110CM45CMDAA*NICE*HONEYWELLC645A1022PRESSURESWITCH*USED*GENERALELECTRIC5KSP51GL*USED*YAMATAKESL1-ELIMITSWITCH*NEWINABAG*FALK02466551050THUBRSB*NEWINABOX*SPIRAXSARCOVS-206STEAMTRAP3/4"*USED*FARADAY6114B-0-15-120-?60HORN*NEWINABOX*EMERSONFX-455POSITIONINGSERVODRIVE*USEDFESTODSNU-25-15-P-A*NEWOUTOFABOX*WEIDMULLEROSTEG7OPTOCOUPLER24VDC*USED*DANFOSSCI16*USED*GOSWITCH7D-43658-DCAPROXIMITYLIMITSWITCH*USED*MARKEM2050MARPRE-HEATER*USED*WILKERSONL01-02-M00LUBRICATOR1/4"*USED*LOTOF2GENERALELECTRICCOIL15D4G2115V*USED*MILLERFLUIDPOWERCYLINDERA72B2C(RUSTYASPICTURED)...LOTOF3RELIANCEELECTRIC45C60DUAL115VAC,2AOUTPUT...M&P,INC.OILFILTER,FILTERREGULATORL28W-2/CFR60...LOTOF7MERLINGERINC60N2A-TYPEB*USED*STATICORING6NN-Y3-N5-C1A*USED*MAGNETEKJA2N12N#311/25HP115VSHADEDPOLE*USED*ALLENBRADLEY20BD8P0A0AYNAND?0SERIESBPOWERFLEX700*...TRANSDUCERTECHNIQUESTM-2*NEWINBOX*DOMNICKHUNTER2858-5*USED*IFMIF0311*USED*KBELECTRONICSINC.KNMD-240D*USED*PARKERPA36RX21SOLENOIDCOIL53VDC*USED*CSID24170/450016CHANNELMULTIPLEXERBOARD*USED*NO***ON109729A*NEWINBOX*ESCORTMEMORYSYSTEMSCM42*NEWINBOX*BAILEYIMLM01*NEW****CSOLENOIDVALVEVG342-5DZ-04FA*NEWOUTOFBOX*BALLUFFBES516-3005-G-E5-C?-S49*NEWINFACTORYBAG*SPRECHER+SCHUH55-530282G002*USED*SENSUS143-80-2HPNATURALGASREGULATOR*USED*FIREYEE110FLAMEMONITORCHASSIS&COVER,120V*USED*...MARPOSS679200001P*NEWINBOX*SEALEDWILKERSONC18-04-FK00W0-122773CIRCUITBOARD*USED*LAMBDALND-Y-152*USED*GFCPOWERGH0F324-OVPPOWERSUPPLY*NICE*OMEGAPHOM-10ABNOPOWERSUPPLYCORD*USED*PILZPNOZX3SAFETYRELAY*USED*LOTOF12RITTALPS4584*NEWINABOX*PILZPNOZV30S3S1SZ/1?O*NICE*WATLOW93BA-1DD0-00RR*NEWINTHEBOX*ALLENBRADLEY1A11440VCOIL*USED*SWAGELOKSS-Q***-B-4PFK1*NEWINBAG*BELLOFRAM903078000*NEWINABOX*HOFFMAND-AH8001B*NEWINABOX*LENZEEVD533--E*NEWOUTOFABOX*MASTERPNEUMATICDETROITINC.CFR55-1L15(ASPICTURED)...GENERALELECTRICCOIL22D11G45A50V*USED*LOTOF2BALLASTRONIXINC.REPLACEMENTIGNITORKITBMS-...TURCKN120V-G30-ADZ30?X2-B1131*USED*LOTOF3ADVANCECONTROLTECHNOLOGYB40033AFD2B607*USE...***CCLAMPCYLINDERCK1T50-175Y2PN*USED*LOTOF4RELIANCEELECTRIC45***2DUALELECTRONICINPUT...ALLENBRADLEYLOGIX5550PROCESSORUNIT1756-L1SERIES...WEEDINSTRUMENTSSP451-PD.3-J-12?.0-A1.50-2006*USED*SOR6TA-EE5-N4-C2A-?CGRR*USED*NEWPORT400AS-4-A3-D2*USED*120/240VPARKER71315SN2KNJ1N0D?1P1C2*USED*LOTOF2MERLINGERINC60N-84TYPEB*USED*LOTOF2CUTLER-HAMMERWMS3D20415V*USED*MICROSWITCHFE-MLS2EA*NEWOUTOFBOX*MSD,INC.326XBX48PTIMEDELAYRELAY*USEDTELEMECANIQUEXCK-MWITHZCK-M1LIMITSWITCH*USED*FOXBORO763RNA-C763RNA-C-E300-0?-0-0-0-0-0-0-0*NEWIN...FINCOR10428461*USED*CROUSE-HINDSAR-331*USED*PARKERVALVE***-20BAMAC56C-13-501JC*USED*SEW-EURODRIVEFSKF321EPH04/13?/06*NICE*LOTOF2TRI-TRONICSBF-B-36*USED*UNISTATUSIS-120QC*USED*MERCOIDCONTROLDA-41-2-23E*USED*ALLENBRADLEY592-JOV16SERIESB*USED*ALEMITE7118-1*USED*SIGNET3-2720PREAMPLIFIER*USED*WESTINGHOUSEA201K4CA*USED*HONEYWELLC6045D10191*USED*MEASUREMENTTECHNOLOGYMTL221OB*USED*OVCVALVE2-CF8M*NICE*GESNUBBERCARDCF12014AAG01*USED*MAGNETAGGSU50Z.I*USED*EFECTORIM350*NEWINABOX*SENTROLINDUSTRAL129-6N-12J*USED*P*USED*)