描述
PLC的控制方式属于存储程序控制,其控制功能是通过存放在存储器内的程序来实现的,若要对控制功能作必要修改,只需改变控制程序即可,这就实现了控制的软件化。可编程控制器的优点在于”可”字,从软件来讲,其控制程序可编辑、可修改;从硬件上讲,其外部设备配置可变。构建一个PLC控制系统的重心就在于控制程序的编制,但外部设备的选用也将对程序的编制产生影响。因此在进行程序设计时应结合实际需要,硬、软件综合考虑。本文就硬、软两方面,选取梯形图为编程语言,以松下电工FPO-C32型PLC为例,对PLC使用过程中易出现的几个问题及解决方法进行了分析。
一、外部输入设备的选用与PLC输入继电器的使用
1.外部输入信号的采集
PLC的外部设备主要是指控制系统中的输入输出设备,其中输人设备是对系统发出各种控制信号的主令电器,在编写控制程序时必须注意外部输入设备使用的是常开还是常闭触点,并以此为基础进行程序编制。否则易出现控制错误。
在PLC内部存储器中有专用于输入状态存储的输入继电器区,各输入设备(开关、按钮、行程开关或传感器信号)的状态经由输入接口电路存储在该区域内,每个输入继电器可存储一个输入设备状态。PLC中使用的”继电器”并非实体继电器,而是”软继电器”,可提供无数个常开、常闭触点用于编程。每个”软继电器”仅对应PLC存储单元中的一位(bit),该位状态为”1″,表示该”软继电器线圈”通电,则程序中所有该继电器的触点都动作。输入继电器作为PLC接收外部主令信号的器件,通过接线与外部输入设备相联系,其”线圈”状态只能由外部输入信号驱动。
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
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National Instruments NI PXI-1031 4 slot PXI chassis
RED LION CONTROLS Model:LGPB QTY:2
National Instruments NI PXI-6527 Digital I/O PXI 6527
National Instruments NI PXI-6713 Analog Output PXI 6713
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DALSA CORECO iMAGING Frame Grabbers Bandit II Bandit 2
HP 744/132L A4500 VME Boards With 256MB STACKABLE RAM
Koyo Direct PLC Direct Logic PLC CPU DL240 D2-240
HP 82341D HPIB PNP Adapter ISA HP P/N 82341-26503
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TEKNIC SST-1500-131 OPT:ACX SERVO STEPPER DRIVE 2 unit
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NATIONAL INSTRUMENTS NI PMC-GPIB PMC GPIB IEEE 488.2
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NuDAQ 6208 Series Multi-channel Analog Output Board
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JAI CV-M50 CVM50 CCD INDUSTRIAL VISION CAMERA
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ADVANTECH PCA-6653 FLAT PANEL/CRT VGA CARD REV.B1
ADVANTECH PCI-1756 64-channel Isolated Digital I/O Card
Agilent 10460A 10461A TTL CLOCK DATA POD
Agilent 1152A 2.5GHz Active Probe
Agilent/HP 54006-68701 Pack of 5 450 Ohm Resistors
HP/Agilent 5086-7968 26.5 GHz Dir Coupler
Agilent 87222E Coaxial Transfer Switch DC to 50 GHz
Intel SBCECMM2 SBCE Accessory Management Module 2
SIEMENS LOGO 24RCL PLC 6ED1 053-1HBOO-OBA2
OPTO 22 SNAP-LCM4 SNAP LCM4 CONTROLLER
OPTO 22 SNAP-B3000 BRAIN WITH 5 X SNAP-IDC5
GE Fanuc IC693UDR005FP1 Micro 90 PLC Controller
LOT OF 5 FESTO LRMA-QS-4 PRESSURE REGULATOR
BECKHOFF FC5101 FC 5101 PCI CANopen
LEAG Antriebstechnik AG TFM 060 N7D SERVO DRIVER
Optem 25-70-49.5X SC50 with HITACHI KP-D20BU
Ericsson PM3757U2 Raid Controller Fiber cha&quad eth
ALLEN BRADLEY 1763-L16BBB MICROLOGIX 1100 NEW
AGILENT E1476A 75000 VXI Series C 64 Channel Mux
JFW 50P-1320 solid-state Programmable Attenuato 127dB
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OMRON SYSMAC CJ1G CPU43H NC233 ID261 OD232 PA202 PLC
Toshiba IK-C40MR Power Supply with CCD Camera&Lens
AB MicroLogix 1762-OW16 Relay Module NEW
BOSCH ZS 400 CPU SYSTEM BOARD
IMAGING TECHNOLOGY OFG REV D Frame Grabbers
Maxon Motor Linear Servo Controller
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FORCE SPARC CPU-5V CPU-5V/64-100-2 VME MAINFRAME CARD
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SCION LG-3 Frame Grabber REV B PCI
500 Watt 50 Ohm Dummy Load
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Agilent/HP 33321-60068 Step Attenuator,0-35dB
MuTech M-Vision MV-510 MV510 PCI Frame grabber Card
Mutech M-Vision MV1000 MV-1000 PCI Frame Grabber Card
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Nippon ChemiCon 450V 6800UF Capacitor
STI 70027-1000 LCC-FB-AC1-U Light Courtain Controller
COHERENT COMPASS YAG LASER DPY301 II WITH POWER SUPPLY
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