5.1. Setting up open-loop control

To configure the Jrk G2 for open-loop speed control, you should open the Jrk G2 Configuration Utility, go to the “Feedback” tab, and set the “Feedback mode” to “None” (which is the default). We also recommend following the instructions in Section 4.3 to configure and test your motor.

When the “Feedback mode” is “None”, the Jrk calculates its “Duty cycle target” variable by simply subtracting 2048 from the “Target” variable. So a target of 2048 corresponds to the motor being off, while a target of 2648 corresponds to full speed forward (100%), and a target of 1448 corresponds to full speed reverse (−100%).

You can set the target directly over USB, serial, or I²C, or you can configure the Jrk to calculate the target by scaling the reading from an analog or RC input. If you are using an analog or RC input, you will probably want to configure the input scaling settings to map all input values to targets within the 1448 to 2648 range, so that more of your input range is usable. There is more information about setting up the scaling settings in Section 6.4 and Section 6.5.