Datasheet

TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
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Read entire documentation; especially the “Supplemental Directives” on page 224.
 MAIN MANUAL 
In order to use S-shaped ramps with initial start velocity, do as follows:
Action:
 Set RAMPMODE (1:0)=b’10 (register 0x20).
 Set S-shaped ramp type accordingly, as explained before.
 Set proper VSTART > 0 (register 0x25).
 Set VSTOP = 0 (register 0x26).
Result:
The S-shaped ramp starts with initial velocity.
PRINCIPLE:
 The initial acceleration value is equal to AMAX. The parameter ASTART is not
considered. Consequently, ramp phase B1 is not performed.
Figure 25: S-shaped Ramp with initial Start Velocity
If S-shaped ramp with initial velocity VSTART is selected:
Avoid unintended system behavior during positioning mode!
 Keep in mind that the S-shaped character of the curve is maintained. Because
AMAX is the start acceleration value, the ramp will always execute phase B2
which could result in positioning overshoots.
 Use VSTART only in positioning mode if there is enough distance between the
current position XACTUAL and the target position XTARGET .
This will ensure smooth operation during positioning mode.
Turn page for information on how to configure finishing ramps with stop velocity.
v(t)
t
VMAX
B
1
B
12
B
23
B
34
B
3
B
4
B
2
VSTART
S-shaped Ramps
with initial Start
Velocity
NOTICE