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IM483 Operating Instructions Revision R032306
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IM483 Operating Instructions Revision R032306
M i c r o s t e p S e l e c t ( M S E L ) I n p u t s
Another unique feature of the IM2000 is the ability to change resolutions
at any time. A resolution change can occur whether the motor is being
clocked or is at rest. The change will not take place until the rising edge
of the next step clock input. At this time, the new resolution is latched
and implemented before the step clock pulse takes effect.
If a resolution is chosen such that the sine/cosine output of the IM2000
would not land on an electrical fullstep of the motor, then the IM2000
will automatically align itself to the full step position on the step clock
pulse that would have caused the motor to rotate past the full step. The
step clock pulses, from that point forward, will be equal to the selected
resolution. This feature allows the user to switch resolutions at any time
without having to keep track of sine/cosine location. Because of this, the
On-Full-Step output of the IM483 can easily be used to monitor position.
Configuration settings for the Microstep Resolution are located in Section
7 of this document,
Interfacing and Controlling the IM483.
S t e p p i n g
The IM2000 contains a built-in sine/cosine generator used for the genera-
tion of Phase A and Phase B position reference. This digitally encoded
9 bit sine and 9 bit cosine signal is directly fed into a digital to analog
converter.
The step clock (SCLK) and direction (DIR) inputs are buffered using
Schmidt triggered buffers for increased noise immunity and are used to
increment or decrement the sine/cosine position generator. The position
generator is updated on the rising edge of the step clock input. It will
increment or decrement by the amount specified by the microstep resolu-
tion select (MSEL) inputs.
The direction (DIR) input determines the direction of the position genera-
tor and hence the direction of the motor. The DIR input is synchronized
to the SCLK input. On the rising edge of the SCLK input the state of the
DIR input is latched in. The position generator will then look to see if
there has been a change in direction and implement that change be-
fore executing the next step. By utilizing this method to implement the
direction change, the noise immunity is greatly increased and no physical
change in the motor occurs if the direction line is toggled prior to the
step clock input.
The enable/disable input does not affect the step clock input. The sine/
cosine generator will continue to update if a signal is applied to the step
clock input.
The IM2000 outputs both sine and cosine data simultaneously when
applying a step clock input. Dual internal look-up tables are used to
output a unique position for every step clock input to enhance system
performance.
