TMC5031 Datasheet, PDF (41/63 Pages) TRINAMIC Motion Control GmbH & Co. KG. – Dual, cost-effective controller and driver for up to two 2-phase bipolar stepper motors.

TMC5031 DATASHEET (Rev. 1.07 / 2013-APR-30)
41
As target positions and ramp parameters may be changed any time during the motion, the motion
controller will always use the optimum (fastest) way to reach the target, while sticking to the
constraints set by the user. This way it might happen, that the motion becomes automatically
stopped, crosses zero and drives back again. This case is flagged by the special flag second_move.
9.2.2 Start and Stop Velocity
When using increased levels of start- and stop velocity, it becomes clear, that a subsequent move into
the opposite direction would provide a jerk identical to VSTART+VSTOP, rather than only VSTART. As
the motor probably is not able to follow this, you can set a time delay for a subsequent move by
setting TZEROWAIT. An active delay time is flagged by the flag t_zerowait_active. Once the target
position is reached, the flag pos_reached becomes active.
v
motor
stop
VMAX
V1
acceleration phase
AMAX
deceleration phase
DMAX
acceleration
phase
VSTOP
VSTART
0
t
VACTUAL
Figure 9.1 Ramp generator velocity trace showing consequent move in negative direction
torque
M_MAX
M_NOM1
high deceleration
2xM_FRICT
motor _torque
high acceleration
reduced decel.
M_NOM2
M_FRICT
0
M_FRICT
Torque available for acceleration A1
reduced accel.
Torque available for
AMAX
Torque required
for static loads
velocity [RPM]
Portion of torque required for friction and static load within the system
M_MAX Motor pull-out torque at v=0
M_NOM1/2 Torque available at V1 resp. VMAX
Motor torque used in acceleration phase Overall torque usable for deceleration
Figure 9.2 Illustration of optimized motor torque usage with TMC5031 ramp generator
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