Current Loop
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Juno Step Motor Control IC User Guide
9
value is value = I * 1.25 * 32,767 / 10.0A and conversely, given a commanded numerical value the equivalent
commanded current in amps is I = value * 10.0A * .80 / 32,767.
9.2.3
Current Signal Calibration
To improve efficiency and motion smoothness it is important that the leg current inputs on signals
CurrentA-D
represent
the actual current value as accurately as possible.
To facilitate this Juno provides the ability to internally zero-out external analog input offsets that may exist while the
motor coils are not being driven by the amplifier and the motor is not moving. This calibration sequence will
automatically measure and set the offsets so that the leg current analog inputs are zeroed out. Because a number of
samples are taken and averaged, 100 mSec should be allowed for this operation to complete.
Analog offsets, unless explicitly stored into NVRAM, will not be retained after a reset or power cycle. For more
information on NVRAM configuration storage see
Section 6.1, “Loading the NVRAM”
Offset calibration of the analog CurrentA-D signals (if used) is recommended for best step motor motion perfor-
mance.
