The application of PIC16F874 on jet loom control system

PIC16F874 in the application of jet loom control system deng-ke xin Joseph welcome to e exhibition hall 3 weaving machinery exhibition hall air-jet loom, rapier looms, knitting machine, knitting machine, jacquard machine, flat knitting machine, circular loom,. 。 。 Running loom because of failure, the other reason such as succession after downtime, can appear when it is between parallel uneven phenomenon, is not between two parallel gap is too big, is the gap is too small, the results will be made by weaving a defective goods, while a stop loss is not too big, but because of downtime is frequent, accumulated loss is big. So you need to in every time before the reboot for weft elastic adjustment, due to its high precision, manual adjustment is hard to adjust to the best state, and time consuming. This controller based on PIC16F874 microcontroller loom elasticity adjusting controller was designed, solved the problem successfully. With high precision, reliable and convenient operation and high cost performance, etc. 1 controller works firmness to adjust the controller is an independent control unit, installed on the loom of the fuselage, the control system are set in the detection circuit, output control circuit, display circuit and so on several parts. The controller principle block diagram is shown in figure 1. Loom during normal operation, adjust the clutch under the control of the MCU PIC16F874, reliable separation of state, in order to ensure the normal operation of the loom. When after downtime for bootable again, adjust the button, the system signal adjustment to adjust the clutch control circuit work, adjust the clutch in the meshing state, adjust the motor in the system at this time under the control of forward, reverse, turn positive &negative and anyway, adjusting weft elastic quantity make its density (right The amount of slack by the workers according to the different set of woven fabric, and stored in the E2PROM chips was introduced) , after the adjustment, the adjustment of the clutch from the state back to separation, and show the end of the elastic adjusting signal. When the textile machine to adjust the clutch is locked in the state of separation. 2 according to the function of the system hardware circuit design, reliable control is the premise, precision is the key. Hardware to simple structure to improve reliability and accuracy by precision gear mechanisms and ensure the detection circuit. The following to the control system of microprocessor ( MCU） Selection and detection part, control part, introduces the setting and display part of the design. Part of the hardware circuit is shown in figure 2. 1 MCU choice due to the adjustment of the system accuracy requirement is high, can be easily set adjustment quantity and power-fail protection role. The Microchip company PIC16F874 microcontroller can meet these requirements of the system. PIC16F874 containing 10 b A/D conversion, high speed, low price, he E2PROM chips was introduced with 128 b electrically erasable memory, can write to adjust volume for later use. 16 f874 and guard dogs, ensure the reliability of the program is running system, at the same time synchronous serial module ( SSP) Lay a foundation for later with industrial computer connected to the Internet. Part 2 detection circuit mainly to adjust the clutch state, spinning machine, such as testing, using photoelectric encoder to improve the detection accuracy at the same time, in order to guarantee the safety of the MCU, all testing signals are connected by optical coupling and MCU. The circuit is shown in figure 2. 3 adjustment quantity setting and display in order to improve the accuracy, adopted the following measures: adopting precision gear retarding mechanism; Improve PIC16F74 working frequency of 20 MHz, only 1 mu s an instruction execution time, and improve the precision of adjustment. As shown in figure 3. Display circuit is used to display setting adjustment quantity. MCU RD0 ~ RD6 as digital section selected signals, RE0 ~ RE2 as digital segment selected signals, DS1 is used to display forward, reverse, turn positive &negative and anyway; The adjustment of DS2 and DS3 display setting. Specific adjustment quantity by S1, S2, S3, S4 button is set to achieve. 4 control circuit of this system to complete control of main motor lock, clutch motor, adjust. By the microcontroller I/O port RA0 respectively, RA1, in RA2 and RA3 output control. In order to ensure the safety of MCU, all of the output control signal through the optical coupling isolation, triode amplifier drive control relay and the field effect tube, the loom achieve fast and reliable control, to ensure the accuracy of adjustment. 3 in software design, software design using modular structure. The process of the main program and each function of program, the interrupt service routine. System software flow chart as shown in figure 4, mainly including the initialization adjust volume Settings, display, control testing the working state of the clutch, adjust the motor working state control. The system has simple structure, stable operation, high control precision, has a perfect protection function, and for further technical improvements have certain resources, low cost, after users reflect the good.