18 IM805 Operating Instructions Revision R032306
19
IM805 Operating Instructions Revision R032306
The IM2000 will automatically change the non-recirculating pulse widths
to compensate for changes in supply voltage and accommodate a wide
variety of motor inductances. This method also allows for the use of very
low inductance motors with your IM805 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 IM805 is an active high output at
connector P1:8. 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 num-
ber 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 and Controlling the
IM805
.
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 IM805 looks to see if any changes
have occurred to the direction and microstep resolution select inputs. If
a change has occurred, the IM805 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 IM805 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.
