Description
PM665 3BDS005799R1 ABB Controller Module
PM665 3BDS005799R1 ABB Controller Module
PWM controller, what does PWM controller mean?
PWM controller , what does PWM controller mean?
Basic principles and application examples of pulse width modulation
Pulse Width Modulation (PWM) is a highly effective technique that uses the digital output of a microprocessor to control analog circuits. It is widely used in many fields, from measurement and communication to power control and conversion.
Analog circuits
Analog signals can vary continuously, with no limitations on their time and amplitude resolution. A 9V battery is an analog device because its output voltage is not precisely equal to 9V, but varies over time and can take any real value. Similarly, the current drawn from a battery is not limited to a set of possible values. The difference between analog and digital signals is that the latter’s values typically belong to a predetermined set of possible values, such as {0V, 5V}. Analog voltage and current can be directly used for control, such as controlling the volume of a car radio. In a simple analog radio, the volume knob is connected to a variable resistor . Turning the knob increases or decreases the resistance; the current flowing through this resistor increases or decreases accordingly, thus changing the current driving the speaker and consequently increasing or decreasing the volume. Like radios, the output of analog circuits is linearly proportional to their input.
While analog control may seem intuitive and simple, it is not always very economical or feasible. One reason is that analog circuits are prone to drift over time and are therefore difficult to adjust. Sophisticated analog circuits capable of solving this problem can be very large, bulky (like old-fashioned home stereo systems), and expensive. Analog circuits can also generate significant heat, with power consumption proportional to the product of the voltage and current across the operating components. Analog circuits can also be very sensitive to noise; any disturbance or noise will almost certainly alter the current value.
