Voltage Following

All controllers made by 4QD work with a voltage input, normally derived from a potentiometer. However, it’s the voltage input that determines the speed so you can feed them from a microcontroller or other voltage source [voltage following].

Our Pro-100 / 160 / 360 models have a “Volt” mode input that disables the usual pot checks. They [and the Pro-150] also have a “pot learn” function that can be used to set the voltages that define the stop, full ahead, and full reverse signals for the controller.

Our older models will require a 10k resistor to be fitted in place of the pot to prevent the pot fault detection circuit from operating. Use the controller’s gain preset to adjust the output to suit [Note, the Porter range do not have a gain control].

In the case of a feed from a microcontroller, you’ll normally be using a PWM output and adjusting the PWM duty cycle. The controller will react to the PWM’s average voltage as if it was a straight d.c. voltage. Depending on the frequency of the PWM signal, you may need to fit an RC smoothing filter on the input.