DC Motor Control Using PIC12F675 achieve
Current requirements are not too high speed for small devices, such as diazo printer, using SCR phase control, supply DC motors. Also use double-base management, to generate pulses. Replace the control with a single chip now possible. Production without debugging, add a host of features such as zero start (removed external hardware chain), optional features such as speed up time. Make the system easy maintenance, reliable operation.
Direct motor control circuit shown in Figure 1. PIC12F675 has six I / O, now with four. Set GP1 to A / D input, as the speed of a given population, are electric positioner 0-5V input. A zero interrupt input, received zero pulse A will produce a voltage over GP2 Department. Set GP3 and GP5 for general I / O, GP3 input for the open stands, received a switch. GP5 for the pulse output by the transistor base resistance on the trigger received.
Trigger control methods: the full-wave rectifier output capacitor filter before removal with zero-crossing pulse triode. GP2 interrupt, on the half-frequency timer (phase angle of the counter) is cleared. Said phase angle counter from scratch, and then use the TMR0 overflow interrupt 100μs (of course, can be further smaller, to increase the angle of resolution), the timer interrupt frequency on half plus 1, and compare the phase angle given, whether equal? If equal, fat pulses to allow the signal to ON, pulse frequency has been sent to the end of half. Made multi-pulse reason for this is the special requirements of DC motor. 0-90 degrees in phase angle, back EMF is greater than the supply voltage, the hair trigger pulse also can not trigger SCR. Not trigger SCR with a pulse. Must wait until the motor speed down, back EMF is less than supply voltage to trigger the SCR, resulting in the current jump, speed bounce. With multi-pulse trigger, the first can not trigger the second third ... ... the trigger adaptive and effective.
Speed rise time control: the amount and half with a follow timer frequency comparison, such as equal, fat pulses to allow the signal to ON, follow the traffic to follow a given speed. Follow the approach is set according to user's requirements, the size of time, time into the comparison, the following volume controls plus or minus 1.
You can also set the start of the crawling speed, speed limiter and so on.
The circuit used in diazo printer, remove the zero starting external hardware chain, starting time meet the requirements to run smoothly.
DC Motor Control Using PIC12F675 achieve
Figure 1 tributary of the motor control circuit
Description: The motor capacity of 200W, all the diodes selected 1N4007. SCR election 5A. Transistor V1, V2 with the 2SC1213 (30V 0.5A). Pulse transformer ratio of 1:1:1. R1, R2 = 10kΩ. Motor capacity increases, the controllable 50A, in addition to the main circuit components, the other component parameters remain unchanged.
Tianjin Integrated Flying Star Photocopying Machine Technology Co., Ltd., after many experiments to prepare a small amount of sample production.
The system is low cost, easy-to-production debugging, after setting the speed can not be retained, the software slow start, will not hurt the hardware, reliable operation.