GCODE - Find current Z axis steps per unit

[stochastic forest]

Hi all,

would anyone know how to find the current setting of the Z axis steps per unit?

I've found:

M92: Set axis_steps_per_unit

to set them, but haven't spotted a command to read them so far.

I need to adjust mine by 0.6%

As a secondary question, does anyone use the hysteresis values ? 

Thanks

[daprigoo]

I don't believe Marlin has a function to output steps per unit settings. There is a value defined in congfiguration.h and you can set one via M92.

I note down what settings I use each time.

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[barnaby]

If we had the EEPROM Chitchat stuff enabled M502 would tell you, but I
we can't fit this and the SD and the Bootloader into the 644's flash.

My version of the Firmware for rounds 2/3 has this as 2560. i.e. 1.8°
motors 1/16 stepping 1.25mm pitch M8 lead screws.

I don't think we have pulled the M98/M99 hysteresis stuff into the
TVRRUG firmware yet.

[stochastic forest]

Thank you for that,

I've seen 

#define DEFAULT_AXIS_STEPS_PER_UNIT {188.3035, 188.3035, 2284.7651, 757.2218} // Al's TVRR

in configuration.h on line 249.

Which I assume means the step value for the z axis is normally 2284.7651 ?

[barnaby]

You also need to ensure your layer height is an exact number of steps
or you get a cumulative error. 2560 happens to allow most likely values,
but for instance my preferred .3/.35/.4 heights wouldn't be suitable at
2714

[barnaby]

Basic maths fail! but the point stands 2575 doesn't allow .3/.35

[stochastic forest]

I see the V1 branch has 2284.7651 and the master has 2560 for Z axis steps.

My Marlin software reports Version 1, in response to M115.

So I may have to experiment.

[stochastic forest]

Measurement suggested the firmware value I have to be 2560 and the most accurate value to be 2545.

I guess using 0.1mm steps in layer height leads to the chosen value to be divisible by 10, 

so for my printer the closest value would be 2540.

2544 is more precise for my printer and is quite nice as it is divisible by both 16 and 3, 

allowing 0.0625 layer steps and 0.33 as well, a sort of imperial metric layer height perspective.

Has anyone experience of using non 0.1mm based layer heights?

[mikethebee]

Hello SF, did you come to any conclusion regarding this thread?? Just for the purpose if updating the documentation mostly - Mike