PCB Tech - Industrial control board and PCB design layout

The industrial control board is an important part of the industrial control computer. To measure a PLC industrial control board, it needs to be decided from the three aspects of its chipset, planning and layout, and work materials. So how to choose a suitable PLC industrial control board? Let's talk about how the quality of the industrial computer motherboard is expressed from the two aspects of the wiring planning and layout of the industrial computer motherboard and the workmanship of the industrial computer motherboard.
The PLC industrial control board is an important part of the industrial computer. To measure a PLC industrial control board, it needs to be decided from three aspects: its chipset, planning and layout, and work materials. So how to choose a suitable PLC industrial control board? Let's talk about how the quality of the industrial computer motherboard is expressed from the two aspects of the wiring planning and layout of the industrial computer motherboard and the workmanship of the industrial computer motherboard.

1. The layout of the PLC industrial control board
In terms of layout, the PLC industrial control board is mainly represented by the organization of various components and the routing of the lines. In the view of Zechuang Weiye, a good PLC industrial control board is an exquisite work of art. Manufacturers supplying chipsets will provide chipset planning guidelines (CHIPSET DESIGN GUIDE) when they ship to industrial computer motherboard manufacturers. At the same time, there will usually be models based on specifications, which we call engineering boards.
2. PLC industrial control board
Large European and American manufacturers often follow the plan of the specification board, and will do very much in line with the standards provided by the official chipset. This approach has guaranteed functions, but the price is difficult to control. Manufacturers in the Taiwan region often make a fuss on the structural layout of the industrial computer motherboard in order to weigh costs, and often incorporate some common plans in it.
3. The structure and materials of the PLC industrial control board
(1) In order to save costs and lower prices, some industrial computer motherboard manufacturers can gain a firm foothold in the market. Not only do they use the number of board types and do not use public version planning, they also have corresponding materials and accessories for industrial computer motherboards. The adjustment is only satisfied with the basic functional requirements of the chipset. This cost-reduction approach is a test of the ability of the manufacturer's industrial computer motherboard to plan the layout.
Put the same number of expansion positions in a smaller space, and maintain stability and limit interference. In this way, the rationality of the industrial computer motherboard structure organization and planning is particularly important. A little unreasonable planning will lead to crashes. In this regard, the poorly capable simply make mistakes in these local areas. The unstable motherboards and poor functions are all caused by this. Therefore, if there are no special requirements, they still use the public version of the planned industrial computer motherboard. It is better. How to distinguish whether it is a public version plan depends on the user's mastery of the chipset.
(2) The position of the interface components on the industrial computer motherboard is generally fixed and cannot be changed at will. Similar to the expansion slots such as PICMG and the keyboard, mouse, USB and other interfaces, it is necessary to cooperate with the holes on the chassis to keep relative The orientation. However, in some cases, a new case baffle will be provided to replace the baffle that comes with the case to complete the new interface layout.
(3) The layout of the CPU and the chipset, because the circuit connecting the CPU and the CHIPSETS is more important, and the chipset has special planning requirements, and the chipset manufacturers also have very clear requirements for the regional planning of the CPU, the chipset and its surroundings., So when planning the layout, the public version is almost used.
(4) Except for the expansion slot, CPU and CHIPSETS, other components can be organized more freely. For example, the ATX power interface socket should be planned to be far away from the CPU fan to allow better heat dissipation in the case.
(5) The layout of the industrial computer motherboard requires reasonableness. Some planning considerations for the industrial computer motherboard are not very comprehensive. If you need to pay attention to some details when purchasing, for example, some industrial computer motherboards have capacitors adjacent to the CPU interface. The devices that will affect the fan, etc., these are the tasks you should pay attention to when buying.

Four, industrial computer motherboard PCB design and wiring planning
(1) Before talking about wiring planning, Zechuang Weiye first tells us about the concept: the interval between the north bridge chip and the CPU and memory is the fundamental requirement of industrial computer motherboard planning, that is, the so-called "clock line is equal in length". We know that the Northbridge chip, which is the bridge between the CPU and the memory, is very sophisticated in layout. Nowadays, some industrial computer motherboard manufacturers with R&D strength choose the wonderful plan of rotating 45 degrees in the organization and layout of the north bridge chip, which not only shortens the wiring length between the north bridge and the CPU, memory slot, and AGP slot, but also makes the clock line equal length.
(2) The wiring planning on the industrial computer motherboard is a relatively professional knowledge, which depends on different circuit characteristics for different planning and processing methods. The "snake wiring" selected on the industrial computer motherboard is very elegant. Some people think that the more snakes, the higher the level of planning. This concept is wrong.
There are two reasons for choosing snake wiring: one is to ensure the equal length of the wiring lines. Because the clock line from the CPU to the Northbridge chip is different from the lines on general electrical appliances, these lines run at a high speed of about 100MHz. The signal is very sensitive to the length of the line. Clock layout lines of unequal length will cause different steps of the signal and form system instability. In this way, some lines need to be routed in a zigzag manner to adjust the length;
Another common reason for using serpentine wiring is to minimize the impact of electromagnetic radiation (EMI) on other parts of the motherboard and the human body. The high-speed and monotonous digital signal will greatly interfere with the operation of the analog equipment on the motherboard. A simple way to suppress EMI is to plan the snake-shaped wiring to absorb and digest the radiation as much as possible.
Choosing snake wiring has the above advantages. It does not mean that the more snake wiring is used in the wiring planning of the industrial computer motherboard, the better. Because too much and too dense motherboard wiring will cause uneven density of the industrial computer motherboard layout, it will The quality of the industrial computer motherboard has a certain impact. Good wiring should make the line density of each part of the industrial computer main board not much different, and it should be distributed as evenly as possible, otherwise it is very easy to cause the instability of the industrial computer main board. How to choose a suitable PLC industrial control board is introduced today, and I hope it will help us.