產(chǎn)品詳情
過程映像輸入/輸出（I/Q）、變量存儲器V、內(nèi)部存儲器位M、定時器T、計數(shù)器C等屬于全局變量。S7-200的程序組織單元(ProgramOrganizationalUnit，簡稱為POU)包括主程序、子程序和中斷程序。每個POU均有自己的64字節(jié)局部變量，局部變量只能在它所在的POU中使用。與此相反，全局變量可以在各POU中使用。
下面是子程序可以使用的局部變量：
1)TEMP(臨時變量)是暫時保存在局部數(shù)據(jù)區(qū)中的變量。只有在執(zhí)行該P(yáng)OU時，定義的臨時變量才被使用，POU執(zhí)行完后，不再保存臨時變量的數(shù)值。
2)IN是由調(diào)用它的POU提供的輸入?yún)?shù)。
3)OUT是返回給調(diào)用它的POU的輸出參數(shù)(子程序的執(zhí)行結(jié)果)。
4)IN_OUT是輸入_輸出參數(shù)，其初始值由調(diào)用它的POU傳送給子程序，并用同一變量將子程序的執(zhí)行結(jié)果返回給調(diào)用它的POU。
主程序和中斷程序的局部變量中只有臨時變量TEMP。
具有輸入、輸出參數(shù)和局部變量的子程序易于實現(xiàn)結(jié)構(gòu)化編程，對于長期生產(chǎn)同類設(shè)備或生產(chǎn)線的廠家尤為有用。這些廠家的編程人員為設(shè)備的各組件或工藝功能編寫了大量的通用的子程序。即使不知道子程序的內(nèi)部代碼，只要知道子程序的功能和輸入、輸出參數(shù)的意義，就可以通過程序之間的調(diào)用快速“組裝”出滿足不同用戶要求的控制程序。就好像用數(shù)字集成電路芯片組成復(fù)雜的數(shù)字電路一樣。
子程序如果沒有輸入、輸出參數(shù)，它和調(diào)用它的程序之間沒有清晰的接口，很難實現(xiàn)結(jié)構(gòu)化編程。
子程序如果沒有局部變量，它和調(diào)用它的程序之間只能通過全局變量來交換數(shù)據(jù)，子程序內(nèi)部也只能使用全局變量。將子程序和中斷程序移植到別的項目時，需要重新統(tǒng)一安排它們使用的全局變量，以保證不會出現(xiàn)地址沖突。當(dāng)程序很復(fù)雜，子程序和中斷程序很多時，這種重新分配地址的工作量非常大。
如果子程序和中斷程序有局部變量，并且它們內(nèi)部只使用局部變量，不使用全局變量，因為與其他POU沒有地址沖突，不需作任何改動，就可以將子程序移植到別的項目中去。
IDEC IZBARL IBRC-6012R RELAY BARRIER 16VDC 14mA 250VAC
G79601 Shimadzu SCL-10AVP HPLC System Controller
Enlarge
Shimadzu HPLC System: Freight/ Ground Shipping Possible
SHIMADZU VP HPLC DETECTOR AUTOSAMPLER CHROMATOGRAPH
Shimadzu SCL-10A VP System Controller
Shimadzu SPD-M10Avp HPLC UV/VIS Diode Array DAD
Shimadzu UV-1201 UV-Vis Spectrophotomet?er UV1201
Shimadzu SIL-10A XL HPLC Autosampler
Shimadzu HPLC System: Freight/ Ground Shipping Possible
Shimadzu 10A & VP Series DAD HPLC System
Shimadzu SCL-10A VP System Controller S-R
Shimadzu UV-Visable Recording Spectrophotomet?er UV160U
Shimadzu SPD-10A(vp) Prep Flow Cell
Shimadzu Liquid Chromatograph LC-4A 115VAC 10A 50/60 HZ
Shimadzu RF-540 Spectrofluoroph?otometer & DR-3 Recorder
Shimadzu SCL-10A HPLC System Controller Lab Waters S-R
SHIMADZU MODEL LC-6A LIQUID CHROMATOGRAPH Unit Used
Shimadzu UV-260 UV/VIS Doublebeam-Spec?trometer UV-260
Shimadzu LC10-AT VP HPLC Pump Liquid Chromatograph
Shimadzu LC10-AT VP HPLC Pump Liquid Chromatograph
Shimadzu TMP2003LMC turbo pump
turbo pump, AMAT pump,
SHIMADZU MODEL LC-6A LIQUID CHROMATOGRAPH
Shimadzu SCL-10A System Controller HPLC VP SCL10A LC UV
SHIMADZU UV1601 SPECTROPHOTOMET?ER TESTED
SHIMADZU LC-600 DUAL PUMP LIQUID CHROMATOGRAPH
Shimadzu Chromatograph LC-10AD CDD-6A SCL-10A SIL-10A
SHIMADZU GC17AAF WITH FID DETECTOR SOLD AS IS
Shimadzu SIL-10A Syringe Auto Injector HPLC Cooler Rack
Shimadzu SCL-10A System Controller
Expedited shipping available
Shimadzu Total Organic Carbon Analyzer TOC-4000
MOUNTING BRACKET FOR SHIMADZU AOC AUTOSAMPLER TRAY
Shimadzu FRC-10A Frb Collector S-R
Shimadzu LC-10AD vp SCL-10A vp FCV-14AH Subcontrol LOT
Shimadzu Flame Photometric Detector
Shimadzu AA680U Atomic Absorption Flame Emission Spec
Shimadzu SIL-10A AutoInjector Autosampler LC SCL 10A VP
SHIMADZU SCL-10A SYSTEM CONTROLLER # 3219
Shimadzu Syringe Pump SIL-10A Auto Injector HPLC LC VP
Shimadzu SCL 10-A System Controller S-R
G79602 Shimadzu LC-10ADVP HPLC Liquid Chromatograph
Enlarge
Shimadzu FCV-10-AL-VP Low Pressure Gradient Valve S-R
Shimadzu UV-160U UV-VIS Recording Spectrophotomet?er
G79603 Shimadzu DGU-14A HPLC Degasser
Enlarge
Shimadzu VP Series HPLC
Shimadzu UV-2101PC Scanning Spectrophotomet?er UV2101PC
Includes CPS-260 Cell Positioner
G79604 Shimadzu 228-34736-91 Reservoir Tray
Enlarge
Shimadzu LC10-AT VP HPLC Pump Liquid Chromatograph
SHIMADZU SCL-6B System Controller Chromatograph HPLC
Shimadzu AA680U Atomic Absorption Flame Emission Spec?
Enlarge
SHIMADZU UV-VISIBLE RECORDING SPECTROPHOTOMET?ER
Shimadzu IR-460 DR-11 Cat No 204-08700-01 U-S
Shimadzu LC10-AT VP HPLC Pump Liquid Chromatograph
Shimadzu SIL-10AP AutoInjector SIL-10A Autosampler LC
Shimadzu Auto Injector SIL-6B w/ SCL-6B System Control
SHIMADZU TOC-5000 Total Organic Carbon Analyzer
with Data System-- Tested-Working?-Guaranteed!
One-day shipping available
Enlarge
Shimadzu LC-10ADvp HPLC Pump
Shimadzu RF-535 Fluorescence Detector HPLC Monitor
SHIMADZU MODEL LC-6A LIQUID CHROMATOGRAPH
Shimadzu RF-551 Spectrofluorome??tric Detector
Shimadzu SIL-10AXL autoinjector,sy?ringe pump, FCV-10AL
Shimadzu Spectrophotomet?er DR-15 RF-5000u
SHIMADZU UV-1601 PC UV-VISIBLE SPECTROPHOTOMET?ER
Shimadzu GC-14A GAS CHROMATOGRAPH USED SPL FID install
Shimadzu HPLC HDU-1 Liquid Chromatograph
SHIMADZU RACK FOR SIL-10ADVP (AND OTHER) AUTOSAMPLER
Shimadzu FCV-10AL Degasser Pump Unit Used
Shimadzu UV160U Recording Spectrophotomet?er UV-160U
Shimadzu LC10-AT VP HPLC Pump Liquid Chromatograph
SHIMADZU XRD-6000 X-RAY DIFFRACTOMETER NICE
SHIMADZU UV-160 UV VISIBLE RECORDING SPECTROPHOTOMET?ER
Shimadzu CTO -6A Column Oven HPLC Lab Use
Shimadzu SCL 10A HPLC System Controller
Shimadzu SIL-10A HPLC Auto Injector Sampler Cooler Rack
SHIMADZU SPD-6AV UV-VIS SPECTROPHOTOMET?RIC DETECTOR
SHIMADZU LC-600 LIQUID CHROMATOGRAPH
SHIMADZU UV-1601 PC SPECTROPHOTOMET?ER W/ CPS 240A
Nice Shimadzu CTO-10ASVP CTO-20AS VP Column Oven
Make me an OFFER-I have other Shimadzu Equipment listed
Enlarge
Shimadzu Visable Recording Spectrophotomet?er UV-160U
SHIMADZU RF-530 SPECTROFLUOROPH?OTOMETER MONITOR
Shimadzu HPLC cooler cooling unit sample
GC Shimadzu Split/Splitless Liner 5 pk Restek 20956-213
Shimadzu LC-10AT Liquid Chromatograph HPLC Flow Pump
SHIMADZU AUTO INJECTOR MODEL# ADC-17!
Shimadzu PC-12D-A Assy Board, 222-00978-92, ST3-15-8
Shimadzu TOC-5000A Total Organic Carbon Analyzer
?Shimadzu RF-1501 Spectrophotomet?er Micro oly wil█Fluor
Shimadzu Centrifugal Particle Size Analyzer SA-CP3
Shimadzu GC-14A All Purpose Gas Chromatograph System
Shimadzu Sipper 160 With Accessories And Carry Case
Shimadzu FRC-10A Frb Collector for HPLC
Shimadzu TCC-240A Temperature Controller
LOT OF 2 SHIMADZU CONTROLLERS MODEL# CFC-14PM!
Shimadzu ELECTROCHEMICAL DETECTOR HPLC L-ECD-6A
Shimadzu Liquid Chromatography Pump Model LC-6A
Shimadzu RF-551 PC Spectrofluorome?tric HPLC Detector
Shimadzu RF-535 Fluorescence Detector HPLC
RF5301PC Shimadzu Spectrofluoroph?otometer 381 hours use
SAVE $14,000 Includes Computer, Flow Thru HPLC cell
Shimadzu HPLC degasser degassing unit degas DGU-3A
Shimadzu RF-535 Lab HPLC Monitor Fluorescence Detector
Shimadzu SCL-10A System Controller
SHIMADZU SPECTROPHOTOMET?ER UV-160
Altex Shimadzu 901 HPLC Chromatograph Integrator
Shimadzu SIL-HTa LC Autosampler SILHTa SILHTc HTc HT
Shimadzu UV-160 Spectrophotomet?er CPS-260 Controller Z
Shimadzu SIL-2A AutoSampler SIL-2AS Control Unit Used
SHIMADZU LC-600 Dual Pump HPLC Liquid Chromatograph
Shimadzu UV-260 UV-Visible Recording Spectrophotomet?er
Shimadzu SCL-6B System Controller
Shimadzu SIL-10AF Autosampler
SHIMADZU SCL-6A DETECTOR WITH AUTO INJECTOR SIL-6A
Shimadzu SPD 6A UV Spectrophotomet?ric Detector HPLC UV
Shimadzu GC Autoinjector&Vi?al Carousel AOC 20i,20s EUC
