Hi Ryan,
this is as misunderstandig.
The drivers stay exactly at the value of 0.24V!
I show 0.7V and 9V just to indicate that the voltmeter works correctly along the range and at 0.7V (the target voltage)
Oh, then either your ramps stack is bad or your drivers are.
Sorry that was not helpful. Try taking all the drivers off and testing them one at a time. If that doesnāt work test the board for 12V and 5V at a few places to see if it is working. Unfortunately the quality on these has diminished severely and this is very common now.
I did all this (as written above). I even baught a complete second set.
So i have 2 ramps, 2 arduino and 10 DRVs.
Its the same in any combination, and the steppers work well when configured using the current drawn, not the voltage.
So I conclude that the controllers etc. are OK, but the motors require an unusual voltage setting (of ~ 0.25V).
Did this never ever happen to anybody else?
My last straw was a shipment of 2,000 Drv8825 drivers that were all non-functional. I did get my money back but they paid to ship them to a company in Texas that is selling themā¦so yeah it happens. This is from a company I had been getting a few years worth of 2,000. One day they just stopped working. Then came the 5V regulators, slowly they stopped being able to handle a LCD for long, then they started to pop every single time.
Unless you actually bought real pololus then you have a problem you should easily be able to return.
Sorry if a newb observation, but isnāt the math assuming 2 steppers whereas Alex is using 1 stepper per driver/stepstick?
Ryan, I read this thread in hopes of locating info regarding the benefits of using 1 end stop per axis vs 2. I already mounted both, but if only 2 are needed, then Iāll just not plug in 2. For an MPCNC. I donāt expect an answer here, but if possible, can you link me to that info that I may make an informed choice? TYIA.
It doesnāt matter for series wired steppers.
Typically you either use two with the dual end stop firmware, or none. I have the dual page with info.
I did tests with both firmwares, the result for me is the same. I initially had and currently have the dual version.
In principle, with series wiring of two motors at one DRV, they share the potential (Voltage) -> each one will have 0.35V of 0.7V (if they have the same resistance).
So for me the finding is clear (controllers etc. are OK), even if i feel a bit like not taken serious. I will try to discuss the voltage issue in the reprap forum. Perhaps someone there already has made similar observations.
Regarding the endstops: using one per axis makes absolutely no sense, as the second stepper will move on (if you did not correct the firmware to stop both motors from one endstop signal) and you could damage your mpcnc!
Two endstops per axis allows you to once for all square your machine.
See the section āTesting and Calibrationā on the dual endstop page Ryan already linked, and his posts in the forum
That voltage you are reading is just an adjustment, it is not what the steppers use. At some point JeffeB3 explained chopping to me. Since our steppers are rated for 2-6Volts but higher amps we use series since we have voltage to spare (12-24V power supplies), but we are pushing the amperage limits of the drivers (relatively).
Your steppers are rated at nearly the same as we use, so your drivers should still be at 0.68V or so (0.7V should be fine as I under power ours on purpose). The spec sheet for your steppers has two different values for rated amps, both are still close to ours.
So all of this said and done, with your drivers at 0.25V what happens with your steppers, do they get warm at all with 20+ minutes continual use? Did you get your two sets of ramps and drivers from the same source or different vendors?
Another thing to test is the Input power pin (Corner), does it shoe the same as your power supply, to me it sounds a bit like the drivers are running off the USB.
Ā
Sorry for the late response, I had some other things to do and was busy with the cable chains, soldering etc.
I finally plotted my first crown and will now continue to check the voltage issue.
Some infos:
The boards have been from 2 completely different distributors, so I think chance is good that the DRVs are not from the same serie - but who knows.
And yes, the steppers get slightly warm.
Update:
I checked the voltage as suggested (on the DRV on the corner): itās the same 12V as the power supply, so they donāt run from usb