Current Sensors Experiment

Current Sensing Experiment:

Purpose:

Measuring motor draw current on current sensing pins via the VNH5019 to identify no load conditions and determine no-load threshold to shut off motors.

The VNH5019 provides two current pins to the user, which can be used to measure the instantaneous current absorption by each H-Bridge.

Procedure:

While running a motor through the VNH5019, the current was measured using the Arduino Leonardo via the current sensing pins M1CS and M2CS. Through software, a running average smoothing filter was used to remove inconsistencies in the data. After graphing the current data drawn by the averagre, a threshold was determined. An ammeter was attached to the motor to directly compare the current measured with the Arduino data.

Results:

After reading the current measured by the Arduino, a current range was determined at which the motor ran under no load conditions. From the data, it was determined that under no load conditions, the current draw was between 450 mA and 600 mA. Using the Ammeter as a reference, it was found that the actual current draw of the motor was about 620 mA. The threshold for the current under no load conditions was chosen to be 620 mA.