Datasheet

TMC5130A DATASHEET (Rev. 1.11 / 2015-OCT-08) 76
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Torque for VSTART
Torque available for
AMAX
Torque available for acceleration A1
Torque required
for static loads
torque
velocity [RPM]
0
M
FRICT
M
MAX
VMAX
M
FRICT
Portion of torque required for friction and static load within the system
M
MAX
Motor pull-out torque at v=0
motor torque
M
NOM2
high acceleration
reduced accel.
V1
M
NOM1
M
NOM1/2
Torque available at V1 resp. VMAX
Motor torque used in acceleration phase
high deceleration
reduced decel.
2xM
FRICT
Overall torque usable for deceleration
VSTART
Figure 14.2 Illustration of optimized motor torque usage with TMC5130A ramp generator
14.2.3 Velocity Mode
For the ease of use, velocity mode movements do not use the different acceleration and deceleration
settings. You need to set VMAX and AMAX only for velocity mode. The ramp generator always uses
AMAX to accelerate or decelerate to VMAX in this mode.
In order to decelerate the motor to stand still, it is sufficient to set VMAX to zero. The flag vzero
signals standstill of the motor. The flag velocity_reached always signals, that the target velocity has
been reached.
14.3 Velocity Thresholds
The ramp generator provides a number of velocity thresholds coupled with the actual velocity
VACTUAL. The different ranges allow programming the motor to the optimum step mode, coil current
and acceleration settings. Most applications will not require all of the thresholds, but in principle all
modes can be combined as shown in Figure 14.1. VHIGH and VCOOLTHRS are determined by the
settings THIGH and TCOOLTHRS in order to allow determination of the velocity when an external step
source is used. TSTEP becomes compared to these threshold values. A hysteresis of 1/16 TSTEP resp.
1/32 TSTEP is applied to avoid continuous toggling of the comparison results when a jitter in the
TSTEP measurement occurs. The upper switching velocity is higher by 1/16, resp. 1/32 of the value set
as threshold. The stealthChop threshold TPWMTHRS is not shown. It can be included with VPWMTHRS
< VCOOLTHRS.