A Siemens PLC control cabinet PLC PLC scanning technology when put into operation, the work process is generally divided into three stages, namely the input sample, user program execution and output refresh three stages. Completion of the three phases is called a scan cycle. During the entire operation, PLC's CPU to repeat a scanning speed of the three phases. (A) user program execution stage in the user program execution stage, PLC always follows a top-down order of scanning the user program (ladder). Or to determine whether to perform special functions required by the instruction of the ladder. When scanning each ladder, and always scan the ladder on the left control line by the contact form, and then first left and right, the first order under the control of the line formed by the contact logic operation and based logic operation, refresh the logic coil corresponding bit in the system RAM memory area status; during the execution of the user program, only the input; or refresh the output coil corresponding bit in I / O image area in the state point I / O status and image area data does not change, while the other outputs and soft devices are likely to change in the state and the data I / O mapped memory area or the system RAM, and the exhaust In the above ladder, the results of which came in the following procedures will be used all these coils or data ladder work; contrast, came in below the ladder, which is refreshed logic coil status or data only scan cycle to the next ranked above it on the programs work. In the course of program execution immediately if you use I / O instructions, you can directly access I / O points. That the use of I / O instructions, then the value of the input process image register is not updated, the program directly from the values ??of I / O module, the output process image register will be updated immediately, with input some differences immediately. (B) the input sampling phase input sampling stage, PLC scan mode sequentially reads all input states and data inside them into the I / O image area corresponding the unit. After the end of the input sample, into the user program execution and output refresh period. In both stages, and even if the input data changes state, status, and data I / O cell area in the corresponding image is not changed. Therefore, if the input is a pulse signal, the width of the pulse signal must be greater than one scanning period, to ensure that in any case, the input can be read. (C) the output refresh period after the end of the scan when the user program, PLC enters the output refresh period. In the meantime, CPU according to I / O image area corresponding to the state and data refresh all of the output latch circuit, and then the output circuit drives the corresponding peripheral. In this case, the real output of the PLC. Siemens PLC control cabinet is now used more generally there is a small basic S7-200's. Control cabinet Name: PLC control cabinet control cabinet Overview: PLC integrated control cabinet with overload, short circuit, phase protection and other protection. It has a compact structure, stable, fully functional. You can touch the actual size of the control regulation, in combination, either single-cabinet automatic control, multiple cabinets can also be achieved via Industrial Ethernet or fieldbus network of distribution (DSC) control system. PLC control cabinet can accommodate all sizes of industrial automation and control applications. Widely used in electric power, metallurgy, chemical industry, papermaking, environmental protection, sewage treatment and other industries. Conditions of Use: Power supply: DC DC 24V, two-phase AC 220v, (-10%, +15%), 50HZ Protection class: IP41 or IP20 environmental conditions: ambient temperature 0 ℃ -55 ℃, to prevent direct sunlight; the relative humidity of the air should be less than 85% (non-condensing). Away from strong vibration source, to prevent vibration frequency 10-55HZ frequent or continuous vibration. Avoid corrosive and flammable gases. Contact: Feng Li Star (Mr) Mobile: 15221871358 Tel 021 -61532630 Fax 021 -67766155 Online QQ: 2541732832 Address: Songjiang District, Chen Hua Road 839, No. 65, Lane 1001 Shanghai Qin Bin Siemens in Germany automation and control of a duly authorized partner company sold products, new original, one year warranty, whenever there is any quality problem, unconditional return material (artificial damage, 15 days) Siemens PLC control cabinet door installation works ; Siemens PLC: S7-200CN, S7-200SMART, S7-300, S7-400, S7-1200, S7-1500, ET200, LOGO logic control module. Siemens HMI human-machine interface: TD200, TD400C, TP177A / B, MP277, MP377, TP700, TP900, TP1200, TP1500, SMART700/1000. Siemens converter: MM420, MM430, MM440, G110, G120, 6SE70 works 6RA70 DC converter governor, 3RW30/40/44 soft starter. Siemens CNC system: 802C, 802S, 808D, 802D/SL, 810D, 840D. Siemens servo drives: 611A, 611D, 611U, S120, NCU, PCU, servo motors, low voltage motors. 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