Programmable logic controller PLC runtime panic condition may occur, which result in an estimated loss of industrial production, therefore, first of all to know the causes of panic PLC, for troubleshooting the cause, a software or hardware error may cause the PLC to panic, introduced below: 1, hardware (1) I/O tracking, PLC I/O error is detected automatically, … Continue reading PLC crashes of software or hardware that causes

1. Input sample stageEnter the sampling stage, PLC to scan works in order to sample all inputs input state and stored in the input image register, input mapping registers to be refreshed. Then enters the processing stage, during the program or other phases, even if the input state changes, enter map registers of will not … Continue reading Process and characteristics of PLC program

1. comparison of the DCS and FCSAs shown in Figure 7-28, FCS has broken the traditional DCS (distributed control system) structure. DCS in the field devices and controllers are located in the control room one physical connection. FCS uses a smart device, DCS in the control room of the original control modules, input/output modules in … Continue reading The characteristics and advantages of field bus

Foundation fieldbus (FF,Foundation Fieldbus) is the most promising, one of the most competitive field bus. Led by the Fisher-Rosemount company, ISP organization composed of 80 companies and jointly led by Honeywell Corporation, joint WorldFIP North America comprising 150 companies in Europe, the two groups merged in 1994, established the Fieldbus Foundation, is committed to developing … Continue reading Foundation fieldbus (FF,Foundation Fieldbus)

LonWorks is by United States Echelon launched by its advocates together with Motorola, Toshiba, formed in 1990 and officially announced. Using all 7 of the ISO/OSI model layer communications protocol, using object-oriented design methods, designed to simplify network communication over the network variable to parameter settings, the communication rate ranged from 300bps to l.5Mbps, direct … Continue reading LonWorks field bus

, multi-point interface (MPI)S7-300/S7-400 network PLC via MPI interface, MPI network using global data (Globe Data) communication patterns can be for small amounts of data exchange between PLC. It does not require additional hardware and software, low cost and usage reduction.MPI network is used to connect multiple CPU or device. MPI for RS-485, a multicast … Continue reading Multi-point interface (MPI) and global data sets