TMCL™ Firmware Manual - Trinamic
TMCL™ Firmware Manual - Trinamic
TMCL™ Firmware Manual - Trinamic
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PD-109-57 V2 TMCL <strong>Firmware</strong> <strong>Manual</strong> (V1.00/2010-FEB-18) 92<br />
9.2 Stall detection<br />
The TMCM-109 is offered with stallGuard. In this case the module is equipped with a TMC249 motor driver<br />
chip, which features load measurement that can be used for stall detection. Stall detection means that the<br />
motor will be stopped when the load gets too high. It is controlled by axis parameter #205. If this<br />
parameter is set to a value between 1 and 7 the stall detection will be activated. Setting it to 0 means that<br />
stall detection is turned off. A greater value means a higher threshold. This also depends on the motor and<br />
on the velocity. There is no stall detection while the motor is being accelerated or decelerated.<br />
Stall detection can also be used for finding the reference point. You can do this by using the following<br />
TMCL code:<br />
SAP 205, 0, 5 //Turn on Stall Detection (use other threshold if needed)<br />
ROL 0, 500 //Let the motor run (or use ROR or other velocity)<br />
Loop: GAP 3, 0<br />
COMP 0<br />
JC NE, Loop //Wait until the motor has stopped<br />
SAP 1, 0, 0 //Set this position as the zero position<br />
Do not use RFS in this case.<br />
Mixed decay should be switched off when stallGuard is operational in order to get usable results.<br />
9.3 Fixing microstep errors<br />
Due to the zero crossing problem of the TMC249 stepper motor drivers, microstep errors may occur with<br />
some motors as the minimum motor current that can be reached is slightly higher than zero (depending on<br />
the inductivity, resistance and supply voltage of the motor).<br />
This can be solved by setting the mixed decay threshold parameter (axis parameter number 203) to the value<br />
-1. This switches on mixed decay permanently, in every part of the microstepping waveform. Now the<br />
minimum reachable motor current is always near zero which gives better microstepping results.<br />
A further optimization is possible by adapting the motor current shape. (For further information about TMCL-<br />
IDE please refer to the TMCL reference and programming manual.)<br />
Use SAP 203, , -1 to turn on this feature.<br />
Copyright © 2010, TRINAMIC Motion Control GmbH & Co. KG