Hello. I have a problem with X2 driver.
Firstly, I let it be with only 4 drivers - X with splitter cable for 2 pieces of X. Y, Z and Y2 in port E1.
But my Driver DRV8825 with Vref 0,71 cant provide enough power for 2 steppers. So my cnc track lost steps and final work was awful.
So, now im trying to get to work fifth driver E0. I was advancing according some tips here and like in YT video Teaching Tech, when he compilating Marlin for Lowrider with Dual Z.
Pins for E0 configured to HEAT BED and pins for E0 get to E1 and E1 for E2. Enabled Dual steppers.
But it doesnt move. When I switch port, stepper works.
So i tried FW SKR 1.3 DUAL from someone called RYAN or JEFFEB3 in version Description. But when i tried to Compile. It says, i have conflict of pins in Serial and LCD. On normal Marlin, its Compiled. But E0 stepper X2 doesnt work. I am using RepRap Discount Full Graphic LCD.
Dont know, what to try. Thank you so much
If you wire your dual stepper motors in series your motors will not lose any power and both will receive the same current that a vref of 0.71v equates to (approx 1.5A). Each motor will require about 4v to push 1.5Amps and two motors in series will therefore require about 8v to do the job, as the stepper drivers have 12v at their disposal all will be well.
I wired my splitter cable to have them in series according to wiring manual. But when I rise vref from 0,71 to about 1,20. It starts to clicking in steppers. So how much should i rise vref for splitted driver? Thank you
Nothing…you should set your Vref at the same setting for two motors in series as for a single motor. ie 0.71v
Ok. So there is last option. I made my connectors wrong and there are bad contacts and if there is bigger current, it appears to works wrong. Thats why steppers lagging randomly. So you think DRV8825 at series is ok for 2 steppers and Vref doesnt change, when you have 2 steppers? Thanks
Yes, the DRV8825s are fine driving two steppers, and you want to leave the Vref alone. When they are wired in series (which you need to do), the amperage remains the same across both motors (or maybe it’s the voltage, I can never remember off the top of my head), and they maintain their holding power. The problem is when you wire them in parallel (like the second Z port on a RAMBo), and it divides the current, which causes them to lose torque. So remember to make sure you have them wired in series. There are diagrams in the docs.
Yes, it works. No, it doesn’t cause problems for “normal” builds (even for builds at the larger ends of “normal”). You are much more likely to run into problems with your speeds and feeds, or with difficult stock than loss of power due to running your steppers in series off of one driver.
This is how we drove all MPCNCs for a long time (we started with parallel and double the current, and before we tried dual endstops).
OK, then. I thing, i ve done my connetors bad, So they need to be done all new. Thank you. Ill come back with answers 