MotoHawk:Blocks:Constant Current Control Output

Constant Current Control Output

This MotoHawk™ block allows constant current control on an output resource that supports current measurement.
Current control strategy is detemined by the hardware it is instantiated on. Not all modules support this feature.

Block ID

motohawk_current_output

Library

MotoHawk_lib/Advanced Digital I/O

Description

The output current is continuously monitored as a differential voltage across the internal sense resistor. When the current is in recirculation and the driver is in the off state, the current will decay to the lower limit switch point. When the current reaches the lower limit, the driver will turn on to increase the current until the upper limit switch point is reached. The output current will continue to switch between the switch points, resulting in the desired average current. The switch points are HW dependant by typically set to a fixed +-5% of the commanded current. The switching frequency and accuracy are dependent upon the load inductance and resistance, battery voltage, dither amplitude and frequency, switch points and the commanded current.

Current dither is a method by which the average current is increased and decreased through a solenoid load. The user may program the frequency and amplitude of the dither control. Dither amplitude is implemented by increasing and decreasing the DAC by the programmed dither value. The rate at which the value changes is set by the programmed dither frequency.

Numeric parameter values drive Current, Dither Amp, and Dither Freq inputs. Current and Dither Amp units are uA, and Dither Freq units are in .01 Hz increments. Maximum values for Dither Amp and Dither Freq are hardware dependant

Block Parameters

Parameter Field	Values	Comments/Description
Name	Alpha-numeric text, single-quote enclosed	Choose the Name to reference. No special characters, such as spaces, dashes, commas (underscore allowed).
Resource	Drop-down list	Select from available listings, as appropriate.