Z axis vref is only half of X Y vref, WHY ???
Posted by Electric ant
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Z axis vref is only half of X Y vref, WHY ??? January 13, 2022 03:37PM |
Hi folks,
I have encountered a strange, and potentially damaging, issue with one of my printers. (Feel free to skip to 'First strange bit' for problem, but background info could be useful.
A few years ago I built a printer based on a Prusa i3. It is 12v and runs Marlin 1.0.0 RC2 on a Ramps 1.4 board with the red A4988 drivers.
I call it Crystal cos it has a clear frame.
I have never had the need to update the firmware because it is still does awesome quality prints now.
Since buying an Ender 3 pro (Eddy), I have been itching to upgrade and update Crystal.
The first thing I want to do is just swap the X Y E drivers for DVR8825s, but this will also involve changing the ramps/mega set for another ramps/mega set.
The reason for this is that I want to keep the setup I have now in case anything goes wrong. As it is now Crystal prints better and quieter than Eddy
I can't flash the old marlin again because it was compiled in Arduino IDE 1.0.6, it will not compile in anything later (no idea why), win10 won't run it and my old pc has recently died.
Anyway, I want to try the new marlin 2.0 as well so I thought why not swap out ALL ramps setup for another with drv8825s on x y e and a4988 on z.
I powered up Crystal and set about reading the vref setting on the drivers. Set my meter to 2v and started probing, what I found breaks ALL the rules of vref on the z axis.
Bear in mind that my original setup is all over 5 years old and has never had active cooling on the drivers. All vref settings were reset, without a meter, about 2 years ago. The extruder vref is not important cos that is a different motor to the rest, plus I know it needs tuning anyway. The z axis is dual motor as well.
Everywhere I look it says the z vref (on dual motors) should be approx. double that of the x an y. I can find nothing that says otherwise.
Here's the first strange bit, there is another one as well.
The vref on the x y motors is 0.840v, so I was expecting to see about 1.6v on the z.
The z vref is 0.471v.
Strange bit #2,
The z axis runs silent, although the x y are VERY quiet as well. The x y motors are always cool, and the z motors are always cold.
Eddy's motors get quite warm, even the single z motor. May have to check the vref on them.
Crystal is actually quieter than Eddy - a supposedly 'SILENT' printer. Eddy's extruder fan alone totally covers Crystal's sound while printing.
All 4 motors (x y 2x z) are the same (17HD34008-22B rated at 1.5A).
Is this even possible ??? Am I missing something or is it because my stuff is old ?
With Crystal running like it is, would I really benefit from marlin 2.0 and 8825 drivers or, should I leave it alone ?
I don't like upsetting Crystal, the smallest changes usually alters something.
If anyone can shed some light on this vref thing and the benefits / drawbacks of marlin 2.0, I will be eternally grateful.
Thanks in advance for all and any help.
Electric ant.
I have encountered a strange, and potentially damaging, issue with one of my printers. (Feel free to skip to 'First strange bit' for problem, but background info could be useful.
A few years ago I built a printer based on a Prusa i3. It is 12v and runs Marlin 1.0.0 RC2 on a Ramps 1.4 board with the red A4988 drivers.
I call it Crystal cos it has a clear frame.
I have never had the need to update the firmware because it is still does awesome quality prints now.
Since buying an Ender 3 pro (Eddy), I have been itching to upgrade and update Crystal.
The first thing I want to do is just swap the X Y E drivers for DVR8825s, but this will also involve changing the ramps/mega set for another ramps/mega set.
The reason for this is that I want to keep the setup I have now in case anything goes wrong. As it is now Crystal prints better and quieter than Eddy
I can't flash the old marlin again because it was compiled in Arduino IDE 1.0.6, it will not compile in anything later (no idea why), win10 won't run it and my old pc has recently died.
Anyway, I want to try the new marlin 2.0 as well so I thought why not swap out ALL ramps setup for another with drv8825s on x y e and a4988 on z.
I powered up Crystal and set about reading the vref setting on the drivers. Set my meter to 2v and started probing, what I found breaks ALL the rules of vref on the z axis.
Bear in mind that my original setup is all over 5 years old and has never had active cooling on the drivers. All vref settings were reset, without a meter, about 2 years ago. The extruder vref is not important cos that is a different motor to the rest, plus I know it needs tuning anyway. The z axis is dual motor as well.
Everywhere I look it says the z vref (on dual motors) should be approx. double that of the x an y. I can find nothing that says otherwise.
Here's the first strange bit, there is another one as well.
The vref on the x y motors is 0.840v, so I was expecting to see about 1.6v on the z.
The z vref is 0.471v.
Strange bit #2,
The z axis runs silent, although the x y are VERY quiet as well. The x y motors are always cool, and the z motors are always cold.
Eddy's motors get quite warm, even the single z motor. May have to check the vref on them.
Crystal is actually quieter than Eddy - a supposedly 'SILENT' printer. Eddy's extruder fan alone totally covers Crystal's sound while printing.
All 4 motors (x y 2x z) are the same (17HD34008-22B rated at 1.5A).
Is this even possible ??? Am I missing something or is it because my stuff is old ?
With Crystal running like it is, would I really benefit from marlin 2.0 and 8825 drivers or, should I leave it alone ?
I don't like upsetting Crystal, the smallest changes usually alters something.
If anyone can shed some light on this vref thing and the benefits / drawbacks of marlin 2.0, I will be eternally grateful.
Thanks in advance for all and any help.
Electric ant.
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