hi i just cant get my head around the wiring the external drivers to my ox cnc. i have search a lot before posting and cant find anything about it bord 2,60(C) 1. i made a pic of what i think is correct, am i? 20200127-012043 2. the ? on my pic above what determines the voltage and were dose it come from? is it an power input? 3. i plan to use a M542T driver(s), it is bought as a kit 4 drivers, 4 motors and 36VDC power supply, but as seen in the description the motors are/needs a Voltage of: 4.2V. after reading the driver manual i cant find any mention about voltage regulation or setting voltage. i can only find current. as it is sold as a kit one can assume its compatible. the documentation says other vise or lack off. dose the M542T only output 4,2v regardless what the power supply deliver to it? (it was old as a 4 axis kit before) https://www.omc-stepperonline.com/sale. ... order=DESC 4. the rst,Resume, abort and hold has also a gnd and 5v. are they triggerd with 5v or gnd?
Stepper drivers are CONSTANT CURRENT drivers, so they adjust the output voltage to achieve the set current (Ohms law: V=I*R, where I = constant set by jumper setting, R=constant of the motor windings' resistance), that's why you see nothing about adjusting voltage, its 'automatic'. You DO want low voltage motors as it allows the chopper circuitry in a modern stepper driver to do its job best (fast rise times, good acceleration, less back-EMF, etc) so perfect there Activated by pulling low in default config
ohh thank you very much you probably saved me lots of $$. i didn't know they were constant current. but it makes more sens. but an other question that pop up then, the driver has current setting 3,2 and 3,7. to get to 4.2v i need 1,3ohms (3,2A*1,3Ω=4,16v) i need to measure the Ω in my cables and take. motor ohm(1,2)+cable ohm+resistor=1,3Ω? how delicate is the driver do you need to be on the dot or under, or can you go above just a few %?
Go under, well under Start with low current setting, adjust upward till the motors do not stall under normal operating circumstances, then add just a little more. Max current will result in overly warm motors, wasted power. Put in "just enough" current to get the motors to perform how you want it. Its not that sensitive
