General config questions "need advice"

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Nov 28, 2021, 4:00:08 PM11/28/21
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Hello, I am 2 years behind the project. The last time I turned on my PnP machine was in 2019. Since then, a lot has changed in OpenPnP.

Today reinstalled Linux mint and installed OpenPnP 2.0 and started setting up OpenPnP

what is done

1. Configured all axes to move in the correct direction and homing

2. Lights, cameras, Pumps, Valves  all working


There are three points that I cannot understand. if it's not difficult, give advice in which direction to look.


1. After homing, Z1 remains in the lower position

My Config Shared Z


2. In my axes list, I don't have VirtualAxis zTop and rotationTop, this is the way it should be?


Wiki Example


My config


3. jog control is very slow


I know all these are simple questions, I know I shouldn't ask such questions.

but did not find an answer in the documentation. 

if you tell me which way to look I will be very grateful.



mark maker

Nov 29, 2021, 1:25:02 PM11/29/21

Hi D,

re 1: Need more info, machine.xml and log at TRACE level.

re 2: Virtual Axes should have been automatically created, if you migrate from a version from before Advanced Motion Control. So if you don't have them, you must likely have deleted them manually (you're not the first ;-). You can easily recreate them and assign them to the camera.

re 3: check the Driver feed-rate limit. Delete it (set to 0). 

NOTE: I hope you are using Issues & Solutions extensively. It should tell you the solution for 3.


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Nov 29, 2021, 5:05:26 PM11/29/21
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Hi Mark,
Thanks for your help! 

1. got it, I will do it tomorrow
2. yep I think I deleted it because of the name  "Virtual Axes"  thought it was a demo Axes :)
3. already done.  

watched your last video  "OpenPnP: Automatic Machine Calibration" now everything has become much more understandable!!
And one more question, Lens calibration must be done before or after?  or not required at all ? Since the documentation says that I need to print the calibration pattern on an A4 sheet and calibrate with it, but I cannot because the camera is very close to the table. Or I can change the printing scale?

Thank you very much!

mark maker

Nov 30, 2021, 7:45:23 AM11/30/21

> Lens calibration must be done before or after? 

It does not matter, as the early calibration steps only use the center point of the camera.


Tony Luken has created a great automatic camera and lens calibration, that is now integrated in the OpenPnP testing version:

He has not yet had time to announce it, I guess... So please consider the following just a sneak preview. He will have to make it "official" and get the well-earned praise too 😉 !!

You can use the Advanced Camera Calibration directly from the camera Wizard, but I recommend using it from Issues & Solutions, like the other calibrations. Issues & Solutions will make sure it is done in the right order, and it will make it more automatic, based on the knowledge from previous calibration steps:

Tony Luken wrote this Wiki too:



Nov 30, 2021, 4:39:37 PM11/30/21
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Hi Mark, 
I decided to start over. and use Issues & Solutions


Dec 2, 2021, 1:10:49 PM12/2/21
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Hi Mark,
I set up almost everything with  Issues & Solutions. it's a great tool !
But still, there are a couple of problems that I cannot solve

1. After homing, N1 remains in the lower position

2. Manual and automatic Nozzle changing
     For precise offset calibration of N2 I need to load the nozzle, I have set up manual nozzle change position, and automatic changer but it throws an error anyway.  Where does he get  "16.070mm" ?


Many thanks for your help!


mark maker

Dec 3, 2021, 8:40:22 AM12/3/21

Re 1:

Well, usually the Z is homed first, in order to lift the nozzles out of harms way. It seems your machine does it last, and it seems it does not home to the nozzle balance point.

What switches do you have and what controller do you use?

Re 2:

The test move is done with whatever tool you have selected in the Machine Controls. Each such tool has head offsets (typically the distance from the camera), that are subtracted from the coordinates. So if your left nozzle is selected, it would go beyond the soft limit.

It seems you have the Y axis all in the negative, because you home to max (your homing switch is at the rear end). Are you sure you cannot set a positive homing coordinate on your controller, so that your Y coordinates stay in the positive?


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Dec 3, 2021, 3:02:43 PM12/3/21
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Hi Mark.
Board:  MKS 1.3  With basic end switches
Firmware:  "AXIS=5 PAXIS=5"

About Manual and automatic Nozzle changing
Now everything is good, pushed a little bit away from Soft Limit.

About Z
Yes, I know Z homing needs to be first I have changed it to avoid colliding because the nozzle is not homing in balance point. . In OpenPnP there are settings for homing to nozzle balance point? Or is it in the controller settings?
I tried setting up gamma_min to -27 "Middle of Z travel", and the logic has changed. Now after homing, "N1" is still in the lower position but when I jog "N1"  1mm UP  he goes up then passes the balance point by one mm. And then the "P" button starts working, and when I click on it,  "N1"   goes down exactly in the balance point.
I hope you have an idea where is the problem "I'm already in a panic mode"


# Z
gamma_min_endstop                            1.28^            #
gamma_max_endstop                            nc               #
gamma_homing_direction                       home_to_min      #
gamma_min                                    -27              # this gets loaded after homing when home_to_min is set
gamma_max                                    0                # this gets loaded after homing when home_to_max is set
gamma_fast_homing_rate_mm_s                  60               #
gamma_slow_homing_rate_mm_s                  20               #
gamma_homing_retract_mm                      10               #


About -Y
As I understand it, I have to do 
1. Physically change the End Switch port
2. Physically change Stepper Motor Direction "swap two wires"
3. In config set Homing direction to "home_to_min" and set beta_dir_pin   0.11!  to  "0.11" without "!" for inverting

Thank you so much, I don’t know what I would do without your help!

mark maker

Dec 4, 2021, 4:44:07 AM12/4/21

Hi D.

There are several things you can do.

First your HOME_COMMAND can contain additional moves. So for instance you can do something like this:

G28   ; Home machine the machine, will home Z to gamma_min = -27mm
G0 Z0 ; Balance nozzles at Z0

Then, after the HOME_COMMAND is completed, OpenPnP needs to know the current machine position. This is done by entering the right Home Coordinate on the axes. So now you need to enter 0 on the Z axis (and the right after-homing position on all the other axes):

That is the manual way.

If you proceed with Issues & Solution all the way to the Advanced milestone, you can let Issues & Solutions convert the GcodeDriver to the GcodeAsyncDriver.

Then you can enable Location Confirmation, and disable Confirmation Flow Control, for faster asynchronous operation. As a side effect, this will always update the true position of the machine into OpenPnP, so the homing coordinates on axes don't actually matter, and any future changes in your homing will automatically be corrected:



Dec 4, 2021, 8:37:30 AM12/4/21
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Thanks a lot for the explanation and help, I'll try today. I hope someday I can help others too.
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