L6470 /Soyo SY57ST56-1206A lacks torque at high speed

rx7man · ‎2015-07-31

Posted on August 01, 2015 at 02:59

Hello all, I have a L6470 based board powering a 1.2A/ 12V Soyo SY57ST56-1206A motor, and at low speeds it has the expected torque, but it falls off drastically above 300 pps, and by 600 pps it doesn't move at all under no load (I need torque to 1000 pps, the Soyo datasheet shows I should be able to get about 80% at that point)... Perhaps this has something to do with the BEMF slopes but I can't find any information on how I should set them? Power supply is 4A 12V, KVAL's are set to 0xFF, Voltage compensation off, Full step threshold is at 1000pps right now

#l6470

Enrico Poli · ‎2015-08-03

Posted on August 03, 2015 at 15:08

Hi,

for the voltage mode control parameters configuration you can use the tool integrated into the STSPIN Famili Evaluation Software (BEMF compensation tool).

Please consider that the torque curve of the motor, according to the datasheet, is obtained using a 30 V supply voltage, half-step driving and 1.2 A current.

Driving the motor with a lower voltage reduces the actual maximum speed you can achieve.

Enrico