1756-IF16/ABPLC智能制造

PLC顺序读取每个输入端的状态，并将其存入到我们称之为输入映像寄存器的内在单元中。当进入程序执行阶段,如输入端状态发生改变.输入映象区相应的单元信息并不会跟着改变,只有在下一个扫描周期的输入采样阶段,输入映象区相应的单元信息才会改变。因此，PLC会忽视掉小于扫描周期的输入端的开关量的脉冲变化。
　　2，程序执行阶段
　　PLC从程序0步开始，按先上后下，先左后右的顺序扫描用户程序并进行逻辑运算。PLC按输入映象区的内容进行逻辑运算，并把运算结果写入到输出映象区，而不是直接输出到端子。
　　3，输出刷新阶段
　　PLC根据输出映象区的内容改变输出端子的状态。这才是PLC的实际输出。
　　以上简单说明了PLC的工作原理，下面我们再以实例说明为什么编写梯形图程序，MFR. PART NUMBER DESCRIPTION
 1756-A10 10 SLOT CONTROLLOGIX CHASSIS
 1756-A13 13 SLOT CONTROLLOGIC CHASSIS
 1756-A17 CHASSIS 17 SLOT CONTROLLOGIX
 1756-A4 4 SLOT CONTROLLOGIX CHASIS
 1756-A7 7 SLOT CONTROLLOGIX CHASSIS
 1756-BA1 LOGIX5000 BATTERY ASSEMBLY
 1756-CFM 2 CHANNEL /2 OUT CONFIGURABLE FLOWMETER
 1756-CNB CONTROLNET BRIDGE MODULE
 1756-CNBR CONTROLNET REDUNDANT BRIDGE MODULE
 1756-CP3 LOGIX5000 RS232 PROGRAMMER CABLE
 1756-DHRIO 2 CHANNEL DH+ AND/OR RIO SCANNER
 1756-DNB DEVICE NET BRIDGE/SCANNER MODULE
 1756-DPALEN CONTROLLOGIC SYSTEM DOCUMENTATION SET PRINTED
 1756-ENET ETHERNET/IP BRIDGE MODULE
 1756-GTWY CONTROLLOGIC GATEWAY CONFIGURATION SOFTWARE
 1756-GTWYR SUPT REINSTATEMENT CONTRACT FOR 1756GTWY
 1756-GTWYS SUPT RENEWAL CONTRACT FOR 1756GTWY
 1756-HSC 2 CHANNEL /4 OUTPUT HIGH SPEED COUNTER
 1756-IA16 79-132 VAC INPUT 16PTS
 1756-IA16I 79-132 VAC ISOLATED INPUT 16PTS

 1756-IA8D VAC DIAGNOSTIC INPUT 8PTS
 1756-IB16 VDC INPUT 16PTS
 1756-IB16D VDC DIAGNOSTIC INPUT
 1756-IB16I VDC ISLOTED INPUT 16PTS
 1756-IB32 VDC INPUT 32PTS
 1756-IC16 VDC INPUT 16PTS
 1756-IF16 ANALOG INPUT-CURRENT/VOLTAGE 16PTS
 1756-IF6I ISOLATED ANALOG INPUT-CURRENT/VOLTAGE 6PTS
 1756-IF8 ANALOG INPUT-CURRENT/VOLTAGE 8PTS
 1756-IH16I VDC ISOLOTED INPUT 16PTS