Home Z-Axis Twice
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@robinfaurecia said in Home Z-Axis Twice:
M574 X2 Z1 S1 ; Set active high endstops
That command in config.g says that your Z endstop is that the axis minimum, i.e. bed as high as it can go or gantry as low as it can go.
G1 S1 Z805 F3000 ; move Z up stopping at the endstop
That command says you are homing to maximum Z, i.e. bed as low as it can go, or gantry as high as it can go.
Which are you trying to do? Does the bed move in Z, or the gantry?
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@dc42 we will change M574 command!
Our bed is moving and the gantry is fixed in z (only moving x/y).
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@robinfaurecia said in Home Z-Axis Twice:
@dc42 we will change M574 command!
Our bed is moving and the gantry is fixed in z (only moving x/y).
So you trying to home to maximum Z, i.e. bed at the bottom - correct?
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@dc42 exactly, that´s right!
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@robinfaurecia said in Home Z-Axis Twice:
@dc42 exactly, that´s right!
So remove the G92 command from your Z homing sequence, and the M208 Z limit will define the position when the homing switch is triggered.
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@robinfaurecia said in Home Z-Axis Twice:
@dc42 exactly, that´s right!
Hi,
Why are you wishing to home at Z max (bed at bottom)?
Frederick
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@fcwilt
Because we thought that it is not possible to print the first layer while the endstop is triggered.
Now we try to home Z at Z max. If this makes to much problems we want to change the endstop position to Z min. -
@robinfaurecia said in Home Z-Axis Twice:
@fcwilt
Because we thought that it is not possible to print the first layer while the endstop is triggered.
Now we try to home Z at Z max. If this makes to much problems we want to change the endstop position to Z min.Thanks.
Go ahead and home to Z min - it will work fine and save time.
Frederick
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Now we can home the Z Axis twice thats good!
But everytime we home Z Axis (doesn´t matter if at Z max oder Z min) we have a difference of 0,2 to 0,5 mm between nozzle and bed. Maybe the difference is caused by hitting the endstop a little bit different every time we home the Z-Axis. Do you have any idea how we can fix this problem?
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@robinfaurecia said in Home Z-Axis Twice:
Now we can home the Z Axis twice thats good!
But everytime we home Z Axis (doesn´t matter if at Z max oder Z min) we have a difference of 0,2 to 0,5 mm between nozzle and bed. Maybe the difference is caused by hitting the endstop a little bit different every time we home the Z-Axis. Do you have any idea how we can fix this problem?
Have you tried reducing the speed of the second homing move, to see if that gives you a more reproducible result?
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@dc42 yes we had already ...second hit is really slowmo but it doesn't help.
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@robinfaurecia said in Home Z-Axis Twice:
But everytime we home Z Axis (doesn´t matter if at Z max oder Z min) we have a difference of 0,2 to 0,5 mm between nozzle and bed. Maybe the difference is caused by hitting the endstop a little bit different every time we home the Z-Axis. Do you have any idea how we can fix this problem?
I've never encountered that. I use micro switches with no arm on them and they work fine.
What sort of endstop are you using? Micro switch? Beam Break? Hall Effect Device?
Frederick
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We are using mechanic switches with a push bar.
I've ordered a bem break now to try if its working better.
@fcwilt -
If you have multiple Z motors, and you are measuring nozzle height at bed centre but the Z microswitch is at the side of the bed, perhaps your Z motors are getting out of sync and the bed is tilting?
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@robinfaurecia said in Home Z-Axis Twice:
We are using mechanic switches with a push bar.
I've ordered a bem break now to try if its working better."Push bar" - you mean the arm attached to the micro switch that presses on the actuator button?
Micro switches usually have more than enough accuracy and repeatability for use as end stops.
I suppose it might be possible that some brands of micro switches are not suitable but I have never encountered any.
"Beam Break" devices can work but they may not yield the crisp on/off action desired.
Frederick
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