PWM Output Modes 9 – 12
PWM Basics A PWM (Pulse Width Modulated) signal is a pulsing voltage whose on-time/off-time ratio varies (duty). This effects the current being supplied to the device ie: A longer on–time will supply more current than a shorter on-time.
Frequency Frequency is normally expressed in hertz (Hz). When a signal cycles from high to low then high again 8 times per second it is expressed as 8 Hertz. ie: 1 Hz = 1 cycle per second, 40 Hz = 40 cycles per second.
Setting the correct PWM output frequency will depend on the device being controlled and can only be obtained experimentally by examining the behaviour of the device.
Duty Within the duration of each cycle the voltage signal will be high for a certain percentage and low for the remaining percentage. A signal whose voltage is high for 50 percent of the cycle duration has a 50 percent duty cycle and therefore supplies 50 percent of the available current.
PWM Frequency Adjustments All STINGER 4 ECUs have 2 frequency adjustments for the PWM outputs. The first adjustment is the Base PWM Frequency. This is an overall adjustment and is applied to all PWM outputs. The second is the Aux PWM Frequency adjustment and there is one for each individual PWM output.
Stinger 4 instruction manual version 2.0