Vacuum packaging machine is a kind of mechanical equipment widely used in packaging industry. Most of the original equipment is controlled by relays with high failure rate, poor stability and single function. Because the NA200 series of small PLCs have the characteristics of high reliability, high cost performance and complete analysis using hard logic. In order to improve the cost performance and reliability of the product, the PLC control system for vacuum packaging machines was developed using the NA200 series PLC, which integrates a variety of functions into one and achieves good economic benefits.

　　(The picture of the vacuum packaging machine comes from the network)

Process requirements

The vacuum packaging machine has four functional gears: sealing, manual vacuum, automatic vacuum and inflation. The four functions are switched by the rotary switch. When switching, it is required to be able to immediately terminate the ongoing function. Internal registers and outputs must be reset before starting a new functional process. The device is equipped with a foot switch controlled by the trigger process input.

The process is described as follows:

1. Automatic vacuum

2. The inflation process

Inflation includes 2 options: Inflation 1 and Inflation 2, selected by the gear switch.

The process of inflation 1 is: vacuum -> inflation (timer 1 controls inflation time) -> sealing.

The process of inflation 2 is: vacuum -> inflation (timer 1 controls inflation time) -> vacuum -> inflation (timer 2 controls inflation time) -> sealing.

System Configuration

The NA200 series PLC is the control core of the vacuum packaging machine system. The peripheral equipment controlled by it includes vacuum pump, air pump, heating wire and position detection switch.

NA200 series PLC configuration is as follows:

The electrical control system of the vacuum packaging machine is composed of NA200 series PLC, which has obvious advantages compared with the electrical control system composed of the original PLC. Mainly manifested in the replacement of multiple time relays by simple man-machine, saving the IO point of PLC and avoiding the problem that the time relay is easily damaged, improving the reliability of the equipment and producing good economic benefits.

The application in the vacuum packaging machine shows that the NA200 series PLC is a small programmable controller with relatively high performance and price. The electrical control system that is more suitable for small mechanical equipment is mainly reflected in the following points:

——The price is low, and the cost of equipment can be well controlled.

——With simple man-machine function.

——Simple programming, easy for electrical engineers to get started.

——Excellent online programming and monitoring capabilities, very practical for on-site debugging.