PLC, programmable logic controllers, industrial automation is the most commonly used controller, electrical automation engineer is most familiar automation products. Today, with the rise of edge computing, PLC such local control device is even more important. Since the PLC and common and reliable in the field of industrial automation indispensable, so now either we or OT PLC of people are curious about why it can be so “bull”, on many occasions irreplaceable? Today, in order to uncover the mystery of the PLC, Xiao Bian take just released this year, Schneider Electric Modicon M262 do an internal dismantling, look at this represent the most advanced technology of PLC exactly what the special design, why do both excellent performance but also has done a super stable and reliable? First look Modicon M262 PLC when it comes to the PLC, one might ask who is this invention. In fact, this is the Modicon PLC (Modicon) company 50 years ago in the invention, and later was acquired by Schneider Electric Modicon become Schneider Electric PLC brand. Modicon M262 is released Schneider Electric Following the M580, M340, M241 and so a set of large and small PLC logic and motion control in one of the PLC, not only excellent performance CONTROL ENGINEERING China Copyright , and further having things directly on the cloud and other functions, can be described as the current representative for the new generation of PLC. So take a look at the interior design of such a PLC also can let you have the latest knowledge of the PLC.
This is the latest to be dissected Schneider Electric PLC – similar Modicon M262, and Iphone mobile phone size, both logic and motion control functions, also has direct on cloud properties and other things.
come to know about the basic components of the PLC before the official start of anatomy, let’s review the basic components of the PLC. By the six most commonly PLC CPU, power, an input circuit, an output circuit, a memory and a communication interface circuit, etc, as shown in FIG principle:
Simple to understand, PLC like a small computer, the CPU is responsible for processing data [ 123] Copyright control Engineering , including logical operations, timing, counting, arithmetical operationCalculation and transmission, a communication network, for programming to compile, execute the command, the result is transmitted to the output. PLC memory (memory) consists of two parts, a system program is stored in ROM, the contents of the read-only memory PLC factory before curing it, the user can not change, the user program and the other is located in the working state data readable write RAM memory. Then there are input and output units and I / O expansion interface, and these are responsible for the connected external device. Finally, there is a power supply module, the external input power after treatment, converted into a DC power to the PLC CPU, a memory, input-output interface required for the internal circuit, for example, 24V. Here, the focus here, exactly what the internal PLC design, making it the date of birth control engineer would favor it? Compared to other control devices, PLC is the biggest feature that is sturdy, simple, reliable, and durable, it should be in the PLC memory and processor selection, PCB board circuit arrangement, the power supply unit and the communication circuit design, the structure design and comply with these characteristics. It can be said, a PLC is capable of long-term stable and reliable operation to determine its quality is good or bad. So, we mainly look at how the reliability of the PLC is designed. First, we turn over the M262, you can see there are four screws at the bottom, but Allen is a common word and can not unscrew the Phillips screwdriver, which also avoids some people feel free to open PLC. We use a special hex screwdriver to easily unscrew the four screws. However, although the screws 4 are screwed down, but still tightly secured together by a snap-lap between the bottom cover and top cover M262. Only the top one using a flathead screwdriver and push them into the bottom cover. After
are all releasably snap-circle, on the smooth bottom cover and separate the cover.
Open the back cover, you can see the back of the motherboard of the M262, green PCB board employed, work well, color uniformity, smooth surface, no odor. Dense pads arranged neatly, but also done a special fixing process, unlike ordinary commercial computer motherboard that has burrs, the hand feels is not stab. Particularly worth mentioning is that the inner cover attached to a stainless steel sheet, on which the installation using a snap for two tracks, the entire steel sheet can not only prevent dust from entering PLC, and can beEMI shielding with good electromagnetic interference, which is very important for the stability of PLC, one would open the lid will see the same design.
After the bottom cover is opened, the cover can be removed directly. After removal, the top and the PLC can see the same two side surfaces are wrapped with a piece of steel sheet, so that, in addition to the two side surfaces for heat dissipation
CONTROL ENGINEERING China Copyright , the four faces PLC EMI shielding are designed. Next, the above M262 shield plate removed, two sides of this sheet by encoder interface hex hex two studs and screws on both sides of the intermediate
CONTROL ENGINEERING China Copyright need to use a screwdriver or hex needle nose pliers to unscrew. After unscrewing the four screws, the shield can be removed, M262 true colors on the whole exposed in our hand. We can see the entire M262 design is very compact, neat. Using a modular structure, easy to implement distributed configuration, a total of four vertical motherboard and expansion boards, board 5 is fixed by a metal frame
, solid structure, earthquake Percussive performance is very strong. 4 plates were extended network communication module, an input module and SD memory card, a power module and an input module. We can pull out the M262 motherboard directly from the bottom. Can be seen a huge aluminum heat sink on the motherboard, the following is the PLC’s CPU, of course, will not use a fan to heat in the PLC. Immersion Gold board all around, both to strengthen the flatness of the board, but also to ensure a good grounding board. The thickness of the board reaches 2mm, stiffness is very good, hands straining breaking has not the slightest deformation.
M262 which is a circuit board input and output modules, has I / O input and output, an encoder interface and expansion interface, as the whole board and motherboard, the design is very neat, sophisticated work.
This is a power supply module. Support 24V DC power supply, while with a normally open watchdog signals. This board is the most significant two large capacitors, and with a plurality of seismic reinforcement made of styrofoam. This filter is used to power electrolytic capacitors, the specification is35V, 1500μf.
This is the stop switch and the SD card, mini USB interface module. The most obvious here is a blue super capacitor (supercapacitor), which is a sudden power failure in the PLC when the power supply to the PLC continues to keep and maintain the data will not be lost with the clock. Before a battery is often used as a backup power source, a super capacitor is now more robust and reliable.
This circuit board is a communication network, a total of three Ethernet ports, wherein the rightmost Sercos support real-time motion control bus. In the right corner and a black small PULSE industrial companies HX5008 Gigabit network filter, in which the back surface is a gigabit network expansion port. Finally, to sum from the internal anatomy of Schneider Electric Modicon M262 perspective, PLC as an important field of industrial automation control equipment, whether internal structural design, workmanship circuit sheet, or opt to use electronic devices followed the controller stability and reliability as the first important principle. Reprogrammable coupled PLC, eliminating manual reset or reconnect the wiring characteristics of the hardware, so that from the beginning of the birth PLC become the first choice of the discrete control. Of course, back to the dismantling of the Modicon M262 controller itself, whether it is the choice of components work or CPU, memory, etc. are very high-end and leading, high-performance processor, large memory, high-bandwidth communication networks, low power consumption this represents the current development trend of PLC.