PDD205A1121 3BHE025335R1121 3BHE025336P201 micro-computer system

PDD205A1121 3BHE025335R1121 3BHE025336P201 uses variable frequency speed regulation to achieve constant pressure water supply. Compared with using regulating valves to achieve constant pressure water supply, the energy-saving effect is very significant. Its advantages are: smooth starting, the starting current can be limited within the rated current, thereby avoiding the impact on the power grid during starting; Due to the decrease in the average speed of the pump, the service life of the pump and valves can be extended; It can eliminate the water hammer effect during startup and shutdown; In boilers and other situations where heavy oil is burned, constant pressure oil supply can make the combustion of oil more complete, greatly reducing environmental pollution.

The PDD205A1121 3BHE025335R1121 3BHE025336P201 control system requires the design of a keyboard, and the conventional approach is to connect each button to an input port. However, as the number of keys increases, it is extremely wasteful of input points. Therefore, following the idea of creating a matrix keyboard in microcomputer systems, PDD205A1121 3BHE025335R1121 3BHE025336P201 uses I/O points to form a matrix keyboard in PLC systems, as shown in Figure 8, which is 3 × 3. Keyboard structure diagram. Programming idea: First, check if there are any key presses on the entire keyboard. The method is to output all rows as 1, and then read the status of the columns. If the status of the columns read is all 0, there are no key presses; if it is not all 0, there are key presses; Secondly, scan column by column by sequentially sending 1 line to check the status of the corresponding column lines. If all column lines are 0, the button is not in this row; If it is not all 0, then the key must be in this row and it is the key that intersects with the 1 level column line. It can be seen that the corresponding software programming is relatively complex, but in some small control systems, it is possible to avoid adding an operation screen or touch screen, thereby improving the system’s cost-effectiveness. If you need detailed hardware design drawings and software programs, you can contact the author.