"wintune" - 1 õppematerjal

Book Analog Interfacing to Embedded Microprocessors

This circuit measures the frequency of the encoder pulses. Using the same 100-to-5000 rpm motor with the same 500-line encoder, a 10 ms sampling clock will give a count of 8 at 100 rpm and a count of 166 at 2000 rpm. The output of this circuit can also be connected to a logic ana- lyzer or DAC/DSO combination. Of course, either circuit can be imple- mented with discrete logic or in a PLD. Commercial Software There are software packages that can aid in tuning PID loops. Examples are Wintune from BestSoft (www.bestsoft.com) and a PID analysis package from National Instruments (www.ni.com). Things to remember in control design: • The accuracy of the system is only as good as the measurement sensor. A thermistor that measures the temperature of the heater will not provide as precise control as one that measures the actual temperature of the heated object. This is especially true of a PID controller, which bases all the control parameters on the sensor input