IM483H/IM805H Rev. R032206
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IM483H/IM805H Rev. R032206
the non-recirculating pulse widths to compensate for changes in supply volt-
age and accommodate a wide variety of motor inductances. This method also
allows for the use of very low inductance motors with your IM483H/IM805H
driver, while utilizing a 20kHz chopping rate which reduces motor heating but
maintains high efficiency and low current ripple.
F u l l s t e p O u t p u t S i g n a l
The fullstep output signal from the IM483H/IM805H is an active high output
at connector P1:12. This output will be TRUE for the duration of the full step.
A full step occurs when either Phase A or Phase B crosses through zero (i.e.
full current in one motor winding and zero current in the other winding). This
fullstep position is a common position regardless of the microstep resolution
selected.
The fullstep output can be used to count the number of mechanical fullsteps
that the motor has traveled without the need to count the number of microsteps
in between. A controller that utilizes this output can greatly reduce its position
tracking overhead, thus substantially increasing its throughput.
Interface guidelines and a sample application for the fullstep output are located
in Section 7 of this document,
Interfacing to the IM483H/IM805H
.
T i m i n g
The direction and microstep resolution select inputs are synchronized with the
positive going edge of the step clock input. When the step clock input goes
HIGH, the direction and microstep resolution select inputs are latched. Further
changes to these inputs are ignored until the next rising edge of the step clock
input.
After these signals are latched, the IM483H/IM805H looks to see if any
changes have occurred to the direction and microstep resolution select inputs.
If a change has occurred, the IM483H/IM805H will execute the change before
taking the next step. Only AFTER the change has been executed will the step
be taken. If no change has occurred, the IM483H/IM805H will simply take the
next step. This feature works as an automatic debounce for the direction and
microstep resolution select inputs.
The reset and enable inputs are asynchronous to any input and can be changed
at any time.