5i25 - Using Encoder on Axis

a z axis stepper loosing steps in a downward direction only is mostly down to using microstepping which is too high , it's rarely needed on a z , higher that half step .
remember the faster an axis goes the less torque it has , idealy a quick remedy is to increase the stepper supply voltage and make sure it has enough amps to supply all steppers

it's also the physics of weight too which dont help , also a reason why z axis is geared .

jds8086 wrote:

SUCCESS!!!, or at least found a work around.

So guess who ordered a 10:1 gearhead.. I know i'm going to sacrifice a little bit of acceleration and a lot of feedrate but at least it will not drift. From what i can tell i will be able to get about 100in/min with the steppers i have.

The other thing that a gearhead can introduce is backlash in the drive train. What type of gear head did you purchase?

cncbasher wrote:

a z axis stepper loosing steps in a downward direction only is mostly down to using microstepping which is too high , it's rarely needed on a z , higher that half step .
remember the faster an axis goes the less torque it has , idealy a quick remedy is to increase the stepper supply voltage and make sure it has enough amps to supply all steppers

it's also the physics of weight too which dont help , also a reason why z axis is geared .

I tried single and half step, the results actually seemed to be worse vs using 5 or 10.

Running ~50V currently (haha see what i did there lol). steppers are 2.2mh inductance

NitroCH3NO2r wrote:

The other thing that a gearhead can introduce is backlash in the drive train. What type of gear head did you purchase?

These are supposed to be max 13arc-minute backlash. And it is new thankfully.

did you remember to change the step values ?
and not just alter the drivers .

i would seriously get this working on either full or half step first , before introducing microstepping ,
this sounds quite alarming .

once you have it correct then introduce microstepping

this sounds more a step configuration mismatch , or mismatched driver setup

are you connecting the +5v for the steppers to the positive side of the opto's in the gekos
and the neg sides to the 7i76 ? .

cncbasher wrote:

did you remember to change the step values ?
and not just alter the drivers .

i would seriously get this working on either full or half step first , before introducing microstepping ,
this sounds quite alarming .

once you have it correct then introduce microstepping

this sounds more a step configuration mismatch , or mismatched driver setup

are you connecting the +5v for the steppers to the positive side of the opto's in the gekos
and the neg sides to the 7i76 ? .

I have the common on the drive hooked to gnd on 7i76 and the step+ and dir+ from 7i76 to drive step and dir input. Should I use 5v for common and step- and dir- instead?

Never fails.. the gearhead i ordered doesn't have the correct bolt spacing for a nema 34 motor.. i thought it was safe to assume that a "NemaTrue" 34 gearhead would fit a nema 34 motor lol.. The other end that bolts to the machine is correct though.. guess i'm gonna have to do some modifications. I only paid $100 for this gear head and from what i can tell i'm not going to find a deal like that ever again if i return it to find something that works out of the box.

yes reverse the sense , place +5v as your common power and use the negatives to the 7i76
you should see an improvement

Looked it over a couple times after making the change and it won't step at all hooked up that way. Gecko manual says to hook it up neg common.

ok , i am lead to believe that geko's are set by default to 10 microstep by default , but please dont take my word , as i dont use them
i'm not sure if you can switch them to say half step etc .

so apart from gearing as your in the process of , and if your setup files are good , then i think your options are low .
so difficult when you dont have the machine in front of you .

The 213v and 210x do have selectable micro stepping. I've tried single and half and both give worse results 5 or 10