Datasheet
TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
102/230
© 2015 TRINAMIC Motion Control GmbH & Co. KG, Hamburg, Germany — Terms of delivery and rights
to technical change reserved. Download newest version at: www.trinamic.com .
Read entire documentation; especially the “Supplemental Directives” on page 224.
MAIN MANUAL
Stall Detection and Stop-on-Stall
TMC stepper motor driver chips with stallGuard and stallGuard2 can detect stall and
overload conditions based on the motor’s back-EMF without the need of a position
sensor. The stall detection status is returned via SPI.
For more information, refer to the AppNote “Parameterization of stallGuard2 &
coolStep” that is available online at www.trinamic.com .
Except for TMC23x and TMC24x, which forward three load detection bits, the motor
stall status is represented by one status bit. TMC4361A is able to stop the internal
ramp as soon as a stall is recognized. Because stall bit activation can occur unwanted
during motion with a low velocity, it is also possible to set up a velocity threshold for
the Stop-on-Stall behavior.
In order to activate a Stop-on-Stall for the internal velocity ramp, do as
follows:
Action:
Set
VSTALL_LIMIT
register 0x67 [pps] according to minimum absolute velocity
value for a correct stall recognition.
Set
stop_on_stall
= 1 (bit26 of
REFERENCE_CONF
register 0x01).
Set
drive_after_stall
= 0 (bit27 of
REFERENCE_CONF
register 0x01).
Result:
The internal ramp velocity is set immediately to 0 whenever a stall is detected and the
following is true: |
VACTUAL
| >
VSTALL
_
LIMIT
.
Then, the
STOP_ON_STALL
event is also generated.
i The status bit stallGuard that is directly mapped from the motor stepper driver,
which is listed in
STATUS
(24). This flag is always activated as soon as the motor
driver generates the stall guard status bit.
i The
ACTIVE_STALL
status bit =
STATUS
(11) is activated as soon as a stall is
detected and |
VACTUAL
| >
VSTALL_LIMIT
.
In order to activate the internal velocity ramp AFTER a Stop-on-Stall, do as
follows:
Action:
Read out the
EVENTS
register 0x0E to unlock the event
STOP_ON_STALL
.
Set
drive_after_stall
= 1 (bit27 of
REFERENCE_CONF
register 0x01).
Result:
The internal ramp velocity is no longer blocked by the Stop-on-Stall event.
i In order to activate the Stop-on-Stall behavior again, reset
drive_after_stall
again
manually to 0.
stallGuard and
stallGuard2
Functionality
Representation
of the Motor
Stall Status
Internal Velocity
Ramp
Stop-on-Stall
Activation
Internal Velocity
Ramp Activation
after Stop-on-
Stall