Reliable plastic pellet machine

　It is another very difficult thing to ensure that the entire system works normally on site. In the past, some units have tried several times to develop automatic controllers for plastic pellets machine, but none have succeeded.

One of the main reasons is that the working environment of the automatic controller of the granulator is very bad. Many types of equipment are in a workshop. Various motors start and stop continuously. The power in the motor can reach more than 13OkW, so the interference is very serious.

These interferences are fatal to the computer system. If the system fails, the system will crash. Once the controller crashes, the consequences can be imagined. Therefore, it is very important to fight interference. In response to the above situation, we have mainly taken the following measures:

　　All input and output, whether it is digital or analog, are photoelectrically isolated. The optical isolation of the switch is relatively simple, and the electrical isolation of the analog is more complicated. Both the cost and the linearity must be guaranteed. We chose a circuit that uses two optical couplings in series and uses the symmetry of the optical coupling to compensate, which not only ensures the accuracy but also reduces the cost.

　　Use one-point grounding for the analog and digital grounds on the printed circuit board wiring. Try to ensure that no two ground wires are parallel. Separate the digital and analog circuits as much as possible to avoid mixed wiring.

　　 Switching power supply with strong anti-interference ability is used as the control power supply. It can ensure normal operation within the range of AC input voltage 120V-27OV.

　　 Arrange the signal lines reasonably and minimize the length of the lines.

　　 After adopting the above measures, the effect is very obvious, and the plastic pellet machine has stood the test on the spot.