The 6MY168-17 intelligent cotton gin is a new generation of high-efficiency cotton processing equipment developed on the basis of the 6MY88-17 and 6MY98-17 brush sawtooth gin units. This equipment is very representative in my country’s large-scale hand-picked cotton processing technology. It has large processing capacity, low production cost, and the quality of the processed lint is good. The drying system ensures the stability and reliability of the complete set of equipment, keeping the blowroom and ginning equipment in optimal working condition. The cotton cleaning roller uses spike components, and the recovery roller uses rack components, which reduces fiber damage. The main gin machine uses advanced equipment such as the 6MPQ400-2800 lint cleaning machine and the intelligent 6MDY400 baler that are matched with the high-efficiency intelligent gin equipment 6MY168-17 gin. The electrical equipment adopts fully automatic intelligent control, and the drying equipment adopts tower drying. Machines and hot blast stoves and other supporting equipment.
The new and efficient 200-type lint stripping machine is used for stripping. Its working box adopts a geometric shape, which improves the operating conditions of the cotton rolls and increases the lint production and cotton processing capacity. It uses double-roller feeding, the traverse plate is made of stainless steel, and a magnet clamp device is added accordingly to prevent iron debris from entering the work box and damaging the saw blade. It is used in conjunction with the 168 large-scale cotton gin to reduce production costs.
(1) Overall structure
This machine is mainly composed of a blowjob and flower feeding part, a ginning part and a transmission system.
(1) The blowroom and flower feeding department is a purification type blowroom and flower feeding machine, which mainly consists of a flower feeding roller and a speed regulating device, an opening roller, a large rack roller, a small brush roller, and a recovery rack roller. , wire brushes, grids and debris removal augers.
(2) The ginning department is the main working part of the ginning machine. It consists of three parts: the front box, the middle box and the rear box.
(3) The transmission system is driven by a 1.1kW planetary cycloidal pinwheel reduction motor to drive the front and rear flower feeding rollers; a 5.5kW 6-pole motor drives the rack roller of the blowroom department; a 1.5kW motor passes through a worm gear reducer (WPD080-1 :40-A) Realize unpacking and closing work; the saw blade roller and brush roller are driven by a 75kW 4-pole motor.
The overall structure, motor transmission, etc. of the 6MY168-17 intelligent gin are basically the same as the 6MY98-17 brush sawtooth gin, but each key part is equipped with a fault detection device, which can automatically detect materials and display faults, and can compare It effectively protects key parts from damage and improves equipment operation rate.
(2) Intelligent system of PLC and touch screen
Traditional cotton gins are affected by complex factors such as cotton grade and cotton moisture regain, which often lead to blockage and affect work efficiency and processing quality. The 6MY168-17 intelligent gin introduces an analog input (saw shaft brush motor current) at the PLC input end, so that the speed of the feeding motor can be automatically adjusted with the change of the saw shaft brush motor current in the gin. When the load of the gin machine increases, the current of the saw shaft brush motor increases, and the speed of the feeding motor automatically decreases; when the load of the gin machine decreases, the current of the saw shaft brush motor decreases, and the speed of the feeding motor automatically increases. This enables the gin to work stably when the load changes due to external factors, and the phenomenon of lap clogging is greatly reduced. It also reduces various switch devices (such as buttons and transfer switches), saves PLC input/output points, provides a good human-machine interface, and opens up a new field for PLC applications. Therefore, it is a good method to combine touch screen with PLC for production control process.
1. Requirements of the process flow on the PLC control system
(1) The work box must be in the closing position before the gin can be started.
(2) When the gin machine is started, the starting sequence of each motor is:
Saw shaft brush motor → Blowing motor → Feeding motor
(3) When the gin machine is stopped, the stopping sequence and starting sequence of each motor The order is reversed.
(4) Once there is a fault during operation, first open the working box, then stop the feeding motor and alarm.
(5) The speed of the feeding motor is automatically adjusted according to the tightness of the cotton roll in the working box, and changes automatically with the current of the saw shaft brush motor.
2. System hardware composition (Figure 8-11)
(1) PLC: PLC is the core of the entire control system, using the main control module CPU222 of Siemens S7-200 series.
CPU222 has 8 input points and 6 output points, and can be connected to 2 expansion modules, with a maximum expansion of 78 input/output points or 10 analog input/output points.
(2) I/O module and interface: The system needs to detect the current of the gin machine host and adjust the voltage of the feeding motor inverter, so an analog input/output module – EM235AI4/AQ1 – must be added.
The input end is connected to digital signals and analog signals. The digital signals are the working box closing and unboxing position signals and the auxiliary normally open contacts of each contactor; the analog signals are the current signals of the main machine of the gin machine.
The digital output terminal is connected to the contactor coil that controls the action of each motor; the analog output terminal is connected to the frequency converter that controls the speed of the feeding motor.
(3) Touch screen: The system adopts Siemens TP27 touch screen, and the RS485 interface is used for communication connection between the PLC and the touch screen. Touch screen software development uses a special configuration tool—Protool software.
3. System software design
(1) PLC programming: In order to easily add or delete program modules, and to facilitate the improvement of different program modules, the program design adopts a modular structure, and the entire program includes initialization, startup , intelligent PID calculation, parking and accident alarm and other programs.
The PLC program module is shown in Figure 8-12.
① Initialization module: Initialize all used intermediate relays M, timer T and data register D, and assign values to some parameters that require initial values (the rated current of the gin machine host corresponds to digital quantity, the digital quantity corresponding to the inverter voltage).
To set the digital quantity corresponding to the inverter voltage, artificial intelligence method is used, and based on many years of processing experience, the grade, moisture and corresponding given digital quantity of the inverter voltage are compiled into a table and stored in the PLC middle. A table lookup program is compiled in the initialization program. By executing the table lookup program, the setting of the digital quantity corresponding to the inverter voltage is completed.
②Startup module: Ensure that each device starts in sequence. The start signal and delay signal of the front start device are connected in series to the drive branch of the rear start device.
③Intelligent PID module: Its program block diagram is shown in Figure 8-13. According to the signal from the current sensor, the intelligent PID algorithm is used to control the input voltage of the frequency converter, change the output frequency of the frequency converter, and adjust the speed of the feeding motor. This module is the key to the transformation of the entire electrical system.
(2) Touch screen software design: Use Protool software to configure various components on the new screen, such as buttons, indicator lights, digital displays and screen selection switches.
The system realizes the operation mode of “one person operation, one button to start and one button to stop”, and has the advantages of high degree of automation and reliable operation. The intelligent control of the feeding motor solves the problem of cotton roll clogging that has existed for many years; the touch screen is used as a human-computer interaction tool, which is simple, intuitive and easy to operate.
The main technical characteristics of the 6MY98-17 and 6MY168-17 sawtooth gins are shown in Table 8-4.
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