1. Equipment Description
The equipment used in chemical fiber repeatedly stretched, curled pre production, mainly by the guide wire rack, eight-stick wire machine, hot water tank, the first drawing machine, water bath, the second drawing machine, steam box, the third drafting machine, folding wire machine, Tension, crimping machine, crimping side motor, pump motor, vibration motor, circulating pump, vibration detection equipment elements. I / O control the scale of 103 points, which switch input point 61, switch output points, 39 points, analog input points to 3 points. Main control requirements are: chemical fiber yarn speed, draw ratio, steam and water temperature, related chain logic control. The key of this system control is to ensure that guide wire, a slight, 2 slight, 3 slight, curly five speed synchronization.
2. System Configuration
System uses Mitsubishi s Q series PLC as the master controller, drive control for the Emerson EV2000 series drives, man-machine interface F940GOT.
System is mainly configured as follows:
???”? Host Controller: Q00CPU: speed and draw ratio given by I / O modules, each machine on site inspection trip, limit switch such as volume and analog signals, control and alarm complete the chain.
???”? Input module: QX40: complete collection site off control,
???”? Output Module: QY10: complete switch output.
???”? Module Input: Q64AD: Analog to complete the on-site inspection.
???”? Serial communication module: QJ71C24N-R4: Communication link form converter.
???”? The transmission drive unit: Emerson EV2000 series drives.
In view of space reasons, this paper describes the key control system design and implementation of the guide wire to ensure a slight, 2 slight, 3 slight, curly five speed synchronization. Customers based on cost factors, transmission drive unit selected Emerson s EV2000 series drives, and asked to form a master controller and the RS485 as the communication medium to low-speed low-cost communications link. Although the guide wire, a slight, 2 slight, 3 pull, curl 5 sets with common DC bus converter operation mode, and install speed incremental encoder constitute a closed loop to improve the speed accuracy, crimping machine converter is also applied to stabilize the tension sensor control the tensile tension, improve fiber quality, but the process starts and stops equipment, especially during operation to adjust the speed and the drawing process parameters than other low-speed communication link in real time when the issues out on the show.
Design, although a communication module 485 can be formed, but because traffic is heavy, we must send the motor speed real-time instructions and start and stop information, while also continue to Duqu inverter voltage, current, frequency and other parameters Therefore, if the use of a module, then the communication cycle will increase, also fail to function in real time. Therefore, we use two 485 modules, namely the four communication port at the same time a slight, 2 slight, 3 slight, curly four frequency communication, and guide wire and a slight share a communication port, in the next cycle of communication. Taking into account the protocol frame length up to 18 bytes, in 19200Bit / s transfer rate, the rate of response to instruction about the maximum time difference is 20ms, the time when the maximum speed for 200M/Min, although a slight lag guide wire, but the process is acceptable. The program can effectively solve the synchronization speed of command ability, to achieve the process of driving off and stopping by order synchronous lifting speed and running speed of adjustment, and five synchronous motor speed fiber drawing tension uniform.
3. Commissioning and experience
In the actual process of debugging, the system basically in line with our anticipated. However, communication debugging, we found that in the Q series PLC communication module equipped with multi-system, communication stability and PLC scan cycle the length of the. With the continued enhancement of the program of continuous improvement, also will increase the scan cycle, when the maximum scan cycle is greater than 25ms, the communication start an unstable phenomenon.
Phenomenon: we QJ71C24 special communications instructions to accept the communication data, when the scanning period of more than 25ms, the communication of 4 at the same time the mouth, placing in the mouth end of the process of a communication error occasionally, when the flag has been accepted transition is ON, said the data has been received complete, but the data area has failed to accept data. We are also procedures for communication of the four port reversing the order found in the situation remains the same, the error occurs only in the order at the end of a mouth.
Analyze the reasons: We believe that the communications timing problems occur, the system flags the jump acceptance and system data transmission is not synchronized, that the systems of internal communication mark the establishment, the communications buffer of the data has not yet had time Chuansong ??????. Therefore we judge to extend the scanning cycle will affect the timing system of communication. The solution: streamline procedures to shorten scan cycle or replace high-speed PLC. However, the large amount of system procedures, and finally to ensure the reliability of the system we will replace the CPU from Q00 Q02, improved system speed, the scanning cycle down to 10ms the following, the problem is resolved.
4. User feedback
This system has been put into the normal three months, the current system is running very stable, reliable, technical specifications fully meet the design effect