Motor current on TMCM-142

[Joggl]

I am currently trying to use an Oriental PK264DA motor on a TMCM-142 powered at 72V. The motor has remarkably low resistance/inductance values (0.3Ohm and 0.6mH). I have now foud that the motor gets quite hot even if it is idle and the idle current (SAP 7) is set to "1" which should be around 300mA. In fact I have measured the phase current and it was 4.5A! After turning on Mixed decay with both run and standby, the current dropped significantly to 60mA peak(?). Still when running with mixed decay, the torque is quite poor and the motor still gets hot.

Would it make sense to change the "Chopper clock divider" (=>"do not change!") to increase the chopper frequency?

[TRINAMIC_BD]

Please check applicable motor driver supply voltage - compare here: viewtopic.php?f=17&t=235&hilit=Vdrv

[Joggl]

Thank you for the advice! Lowering the voltage to 40V has improved the situation drastically.

There is however another question which has come up: As the TMCM-142 offers quite some power, I'm wondering if there's a chance to enable/disable the motor (or at least motion) by a hardware signal other than turning off power and subsequently losing communication and all parameters?

Or, the other way round, is there a way to keep the ARM7 processor and the TMC457 running without motor power? Supplying +5V via the CN1:10 pin (+5V out, yes, I know this is weird) sort of does the job but prevents powering up correctly once the external supply is back.

[Olav Kahlbaum (TRINAMIC)]

If it is no problem to keep the main power switched on one could just set the standby current (axis parameter 7) to zero. This however does not completely switch off the motor driver but the motor current will be very low then.
The TMCM-142 does not have a dedicated "shutdown" input with which the driver can be switched off completely by hardware. But we can in one of the next firmware releases put in a "freewheeling" function also for TMC457 based modules (which can then switch off the motor driver completely whenever the motor is standing).