1) Overview of food packaging machine:
The application of high-tech technological achievements, using electromechanical integration, easy operation, and perfect control program. The pillow-type automatic packaging machine is widely used and has strong adaptability. It can be used for the packaging of biscuits, instant noodles, candy, ice cream and other small foods. It can also be used for the packaging of medicines, parts, textiles, lightening and daily necessities. The total width of the packaging material can reach 450mm, and the packaging size can be freely selected within the range of length (95-350) mm, width (10-140) mm, and height (5-70) mm. The packaging capacity is 30-200 bags/min, the use power: 4KW. Overall size: 5050×960×1800 mm.
2) Composition of electrical system:
The power supply adopts three-phase five-wire system (or three-phase four-wire system) 380V/50Hz power supply, and the power consumption is about 5KW.
The electrical system of the main machine is mainly composed of three parts, the programmable controller (PLC) and the speed sensorless vector frequency converter are the core control part and heating control part.
3) Working principle of automatic pillow
A) Heating system
After the system is connected to the power of the control cabinet, you can choose to heat it. The heater uses a safe voltage of 48 volts. After setting the required heating temperature, it usually takes about 20 minutes to reach the set temperature.
B) Operation and speed setting
The programmable controller can choose manual and automatic operation according to the operation mode. At this time, the "POWER" and "RUN" indicator lights on the PLC device are on. After the adjustment of the film and the packaging (instant noodle noodles), put the operation mode switch SA2 in the "automatic" position and the tracking switch SA3 in the "automatic" position, press the start button SB2, and the vertical sealing electromagnet YA1 attracts and runs The alarm sounds for about 2 seconds when energized, and the machine runs continuously.
The host uses KV2000 speed sensorless vector inverter for speed regulation. The operation keyboard of the frequency converter is installed on the operation control cabinet. The speed regulation is realized by the panel potentiometer R1. The operating keyboard of the inverter shows the motor speed. Speed Rpm=(120×F057 output frequency/F052 motor pole number)×gear ratio. When leaving the factory, the relevant parameters have been set, users generally do not modify the parameters.
C) Differential mechanism and bag length adjustment mechanism of pillow type automatic packaging machine (omitted)
D) Tracking system
The tracking system is the control core of the packaging machine, which is controlled by the PLC program (see some main PLC tracking programs). The system can accurately position according to the shape and size of the packaged items. It uses forward and reverse bidirectional tracking to further improve the tracking accuracy. The errors of packaging materials in the production process are discovered in time, and the compensation and correction are accurately given to avoid the waste of packaging materials. After the machine is running, the film mark sensor continuously detects the film mark (color mark), and the mechanical part tracking micro switch detects the position of the machine. The above two signals are sent to the PLC. After the program operation, the PLC outputs Y6 ( Forward chasing), Y12 (back chasing) controls the forward and reverse tracking of the tracking motor. If the detection still fails to meet the technical requirements after tracking a predetermined number of times, it can automatically shut down for inspection to avoid the generation of waste products;
E) Food packaging machine requirements for frequency converter speed regulation
Although the application function of the transmission system used in food packaging machines is relatively simple, it has higher requirements for the dynamic performance of the transmission. The system requires faster dynamic follow-up performance and high stable speed accuracy. Therefore, the dynamic technical indicators of the inverter must be considered, and high-performance inverters can be selected to meet the requirements.
F) Characteristics of KV2000 speed sensorless vector inverter
1) Application of speed sensorless vector control technology, with automatic tuning function, automatic frequency correction to achieve the effect of motor speed stability when the load changes;
2) It has high speed stability accuracy and fast dynamic response, which can meet the transmission control requirements of high performance occasions. Reduced time and economic losses caused by transmission system failure. At the same time, the speed sensor is omitted, and the maintenance cost is lower.
3) It has the advantages of rich functions, stable performance, miniaturization and low noise operation.
G) In the peripheral circuit of KV2000 inverter, it is mainly composed of six parts
1) DC braking resistor terminals P+ and DB are externally connected to braking resistor R0; when the system is stopped, an instant safe stop is achieved;
2) In the control circuit input terminal, FWD/REV is a forward/reverse signal, where FWD receives the Y0 output signal from the PLC, and the inverter runs forward at the set frequency; X1, X2, X3, X4, X5, X6 are Custom multi-function input selection terminal, where X1 receives the jog signal from PLC program control output Y1, and the inverter realizes jog operation;
3) The frequency setting is set by the potentiometer R1 installed on the electric control cabinet, which is convenient for the field operator to adjust the speed according to the production needs;
4) In the control loop output terminal, TA and TC are inverter fault output terminals. When the inverter fails, the PLC input signals COM, X10 are closed, the program control system alarms and automatically stops.