BlTouch not responding to commands?
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What would be the right way to probe the bed simply center the extruder and issue a G30 command then a G32 of course this is after getting the offsets and heaight of the probe dialed in?
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To home z all you need to do is center the probe and do a G30. If the probe x y and z offsets are all correct you'll get a good representation of z=0 for that point.
There are a few options beyond simple z homing though, and it will depend on your setup what you want to do.
If the bed is flat and already mechanically leveled you can call it a day and print away.
If you have multiple independent lead screws and want to do some leveling of the bed with them that can be setup. You can also have the duet probe close to your adjustment screws and it will tell you how much to adjust them to level the bed. It can also create a simple 5 point tilt plane to adjust for. This would be setup in bed.g and it would be called by G32.
If your bed isn't perfectly flat you can use mesh grid compensation to adjust for it using G29. This probes the bed in multiple points and creates a height map that is saved and can enjoy reloaded so you don't have to probe the bed every time.
So there are a lot of options. Depends what your bed is actually like.
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Well I would like to use compensation since my bed isn't perfectly flat or at the very least it isn't totally flat. I would think being able to level the bed manually to be almost perfectly flat then issuing a G29 would give me the best results.I have 2 leadscrews but they are working together to raise and lower the z axis .
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Yes it would be ideal to get the bed as level as you can with the adjustment screws and then use G29.
It is possible to run each Z motor on its own driver and perform tilt correction between the two, but that's not really needed if the bed is stable and the motors stay in sync as they are.
https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors
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I started setting everything up but I have a small problem.I set the offsets for the Z Probe following the instructions on the guide.I have two problems I believe when I home the z axias it homes to the back right corner of the bed which is the max x and y axis points of the bed as I understand.I tried the G29 with the extruder and probe centered over the bed but when it tried to probe the first probe point the probe misses the bed and it tells me the probe was not triggered.
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@siblues you have to adjust the grid setup in M557.
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This is what is in my config.g
M557 X15:205 Y15:205 S20 ; Define mesh grid
I have a 220 x 220 bed.
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And what is your probe offset in X and Y?
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To get accurate probe results, the Duet needs to know how far the BLTouch is from the nozzle in X and Y. To measure this, place a piece of paper on the bed and use tape to hold it in place. Move the nozzle down until the it touches the paper and leaves a small imprint. Make note of the current X and Y coordinate. Use a marker to make the spot clearly visible. Now jog the print head in X and Y until the BLTouch pin is on the exact spot you marked. Make note of the new X and Y coordinates. The difference between the two will be your X Y offset in the G31 command.
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X -20 y -45
I am also having some issues with my mk8 extruder
.I have a Bondtech BMG on the way and I am going to start looking around for some settings for that.i would like to be able to print some minor parts before installing the Bondtech though. I don't like taking on too many problems at once. -
Try this as your grid size
M557 X50:200 Y50:200 S20 ; Define mesh gridDo you have your XY offset entered into your G31 command in config.g? In your post above with your config in it it's blank.
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I edited the original post in this thread with the current files so you can see what is on the SD card at the moment.
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Did you try with the grid size I posted above?
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I am in the process of doing that as we speak.I just figured I would post the information first.
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@siblues said in BlTouch not responding to commands?:
M201 X500 Y20 Z250 E250 ; Set accelerations (mm/s^2)
This isn't related to your BLTouch at all, but I just noticed that your Y axis acceleration is set quite low. I believe the configurator does this on purpose for i3 style machines because the bed can be quite heavy and a high acceleration can cause it to stall.
Once you've confirmed everything is working you can increase that value. Try matching the X value and if that seems like the movement is too much for the bed, decrease it a bit.
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The mesh grid is working but it seems to be off center.The grid is starting about 1 inch from the left side of the bed and finishes about 1/2 inche from the right and it starts about a 1/2 inch from the front edge but is also an inch from the rear.
I get occasional z probe triggered before move during mesh grid compensation.
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You can make changes to the size of the grid to adjust for that.
X50:200 means it starts at X50 and moves to X200. That's nozzle position I believe. So to make it closer to the left you can make the starting X position closer to your X offset. Let's say X20. That should get the probe close to the left edge. To get it closer to the right, increase the larger X value. So if the extent of travel on X is 220, and the probe is on the left side of the nozzle you can go all the way to the edge, minus the 20mm the probe can't actually reach.
Then if we do the same adjustments for the Y part of the grid... The probe is 45mm behind the nozzle, so when the nozzle is at Y0, the probe is 45mm behind it, so that's teh closest you can get to the front. The extend of travel is 220. So nozzle only has to be 45mm away from there to reach it with the probe. Any further and the probe would be off the edge.
So try
M557 X20:220 Y40:200You don't have to go all the way edge to edge. It will extrapolate the areas it can't reach. The grid spacing will also dictate how far it will go. So try and use a grid spacing that will fit evenly into the distance in X and Y.
To help reduce the triggered before move error you can add some parameters to your M558 probe settings.
Try
M558 P9 H7 F100 T6000 A5 R0.3 B1 -
I trieds what you listed above and it will get closer to edge on the left side but the rear and right side are a no go.I tried adjusting the numbers a few times and if I go above 230 for the grid size it tells me it can't reach the grid points.I think my endstops aren't configured correctly and that may be playing a part in this issue.The endstops for x and y are both off the bed.The extruder is -25 off the bed on the x axis and -35 on the y axis should those numbers be entered into the axis limits?
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I think you should take a look at this
https://drmrehorst.blogspot.com/2017/08/setting-up-3d-printers-origin.html?m=1
It may help visualize the actual size and position of the bed and should make it more clear what your axis minima and maxima should be.
0,0 should be the front left corner of your printable area where the nozzle actually is on the bed. The minima can be right at that point, or it can be further off the bed, in which case you can use a negative number.
So for example if you move the nozzle to 0,0 and then you have to move the head another X-40mm to hit the end stop you could use -40 as your x axis minima. Then from 0,0 you can move x +220mm to the right before it hits the physical end of travel your x axis maxima is 220mm. Same goes for Y.
Once the bed is accurately setup you can more accurately define your grid.
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