I'm about to bite the bullet and start building a 4x4 machine from finelineautomation.com plans. I've been looking at saving a little money (yeah yeah) and found the following on eBay and dHgate. A 2M542 stepper driver with a fairly reasonable price (at least I believe so). Someone in a differant thread mentioned these might be what keling sell. Has anyone tried these drivers and are they any good?
CNC 3 Axis Driver 2M542 4.2A& Breakout board Router kit | eBay
Another question I have is the current limiting resistor. My limited reading has found that the recommendation is to set the driver's switches for full current and then limit the current using an external resistor. does this sound about right?
If anyone is looking for 80/20 look-alike extrusion in Canada try faztek.ca. Based in Quebec, pricing is good and shipping won't be killer like from the states. the aluminum for the entire FLA machine weights in at 166lbs.. One piece of 3030 96" long was going to cost me $150 for shipping plus UPS's innane brokerage fees. I've been looking at CNCrouterparts plans as well. Need to decide whether to build one with a built in stand or one without I guess.
From my reading of the documentation at 2M542-Manual, I believe that the motor current is set by DIP switch only.
The only mention of external current limiting resistors that I found had to do with a completely different purpose, namely to limit the current flowing through the optoisolator inputs for signals such as PLS (step), DIR (direction), and ENA (enable) such that no more than 16mA flows through the LED inside the optoisolators.