New control design scheme of vacuum forming machine system
In the equipment of refrigerator production line, the use of vacuum blister molding machine system is very popular. For each different refrigerator liner model, the process parameters and mold must be adjusted. With the localization of PLC and the continuous reduction of cost, PLC It plays an increasingly important role in the energy saving of industrial production lines and the improvement of production efficiency.
is composed of Siemens S7-200 series PLC and the MT-500 series touch screen of the Human Electromechanical Subsidiary for the working environment and energy-saving requirements of the single-station vacuum forming machine control system.
Siemens S7-200 series PLC has become the first choice for industrial production site controllers with very high reliability and low cost advantages.
It can adapt to strong electromagnetic interference and high temperature and high humidity occasions in the field environment.
The core of the system uses Siemens CPU226 as the module, and then adds O/I expansion modules EM223, EM222, and analog input module EM231, output module EM222.
The CPU226 module has two RS485 interfaces. The point-to-point interface (PPI) is very convenient to use. One can be used for touch screen control, and the other can be used for communication with other company modules.
The man-machine interface adopts the touch screen MT-510T, which is simple and reliable. The reliable communication distance can reach 50 meters when using the RS485 communication line.
2. Human-machine interface
1. Main interface introduction: As shown in Figure 1, boot into the main interface of the system to select the desired working mode. If you select the English work mode, enter the English interface as shown in Figure 2, if you select the adjustment interface or select the manual interface, the system will enter the corresponding control panel to enter the mold assembly debugging and manual reset work.
2. When the system enters the automatic operation control panel, you can understand the operation of the vacuum blister molding machine through the bit status indicator, and the cycle start multi-function button can be completed in different operating states: cycle start-----heating end- ------- Cooling is over, three functions.
3. Action sequence of automatic working cycle:
Loading――――Press the cycle start button――――The pressing frame drops quickly――――The pressing frame lowers slowly to position――――The upper and lower heating plates advance quickly――――The upper and lower heating plates advance slowly to position―― ――The heating plate starts to heat――――A: Normal; set the heating time to――――――――――――
B: Abnormal; sheet material sagging――photoelectric protection switch――――――
C: Manually press the (heating end button) button――――――――
The upper and lower heating plates move back quickly――――The upper and lower heating plates move back slowly in place――
D: On the delay of the mold base―――the set time is up―the mold base moves up quickly――――the mold base moves up slowly in place――――
E: 1 bubble blowing――――setting time up――――2 blowing bubbles――――setting time up――――――――
Slow vacuuming――setting time is up ― fast vacuuming――――setting time is up ―――(select auxiliary pressure frame)
, The auxiliary pressure frame drops quickly――――the auxiliary pressure frame drops slowly――――holding pressure――holding pressure time up――――delayed cooling――setting time up――――cooling fan on―― The set time is up-the fan stops-the vacuum is eliminated-the set time is up-the demoulding blow-the set time is up-the core is pulled back, the mold base is delayed-the set time To ――――The proportion of mold base slowly drops to place――――The core is reset, and the pressing frame rises quickly――――The pressing frame rises slowly――――Unloading,
One work cycle ends. At the same time, if an accident occurs during the execution of the action, you can press the emergency stop button, and the action will stop immediately; all actions are simulated on the touch screen interface.
4. Parameter adjustment: touch the parameter adjustment screen interface to set the product model, action time setting, temperature setting, pressure and speed setting, heating plate heating position and heating power percentage in the production process.
5. Figure 6: Enter the product selection interface, select the product that meets the product process and confirm it according to your needs.
6. Other parameter adjustments enter the corresponding adjustment interface, and adjust according to the product's process card requirements. As shown in Figure 4, 5, 6.
3. Matters needing attention:
1. When wiring, be sure to turn off the power.
2. The power supply of the control cabinet must be a three-phase five-wire system that meets the standard. The grounding terminals on the body of all equipment must be properly grounded, which can improve the safety of the product.
3, AC power cannot be connected to signal terminals such as limit switches, otherwise it may cause serious damage, so please reconfirm whether the wiring is correct before turning on the power.
4. In order to prevent interference, the connection between the touch screen and the control cabinet must be covered with a shielded wire, and it cannot run side by side with a circuit above AC200V.
Fourth, the preparation of the PLC program:
Siemens S7-200 uses Siemens STEP 7-MicroWIN for convenient and quick programming. It can switch programming between STL, ladder diagram, and FBD logic block diagram. The rich instruction set can basically meet the application of small and medium-sized equipment.