Should the Z-probe height need to be adjusted after manually levelling the bed.

I've been struggling to get my printer to print consistently without having to constantly adjust the z-probe height but I can't seem to manage it. recently I printed a number of prints until it stopped printing consistently and became unlevel. So I went through my manual be levelling process and then ran the bed-mapping function (software correction) and when I tried to print after doing that I found that suddenly my nozzle was over twice the distance from the bed (was 0.13, now 0.32). So in order to get it printing again I had to adjust my z-probe height to close that gap again. It seems like I have to constantly adjust the z-probe height between prints when I gets off and I'm struggling to understand why the z-probe height seems to get so inaccurate over time.


  • This is not really a server problem. It should depend on firmware, so which firmware are you using? I would expect firmware to store the good values in eeprom so they stay. For repetier-firmware they stay until a checksum error is detected and the eeprom is reset to configuration.h values.
  • oh interesting, because I whenever I check the eeprom value I would swear it hasn't changed but it's possible I may be remembering an earlier eeprom value. I do see checksum errors pop up relatively frequently so maybe that's what happening without my realizing. do you have a general suggestion for solving checksum errors or do you need more information about my current situation first?
  • I think you are talking about serial communication checksum errors while I meant checksum over eeprom memory, so different things.

    None the less checksum errors are not good also they get corrected. The amount really differs between printers and hosts and cables and baud rates. Some have normally no errors at all while other have errors every now and then (every 1000 lines or so). If you get ver frequent errors (every 10 lines or so) your settings are wrong.

    You can change first changing baud rate between 115200 and 250000 - one of them normally works better. Don't forget you need to change it on firmware AND server to work. Also a different usb cable can improve - shorter and shielded are things having a positive effect.

    You can also try to login over ssh if using a pi and remove modemmanager - it interferes at printer connection with communication as we found out.
    sudo apt remove modemmanager
    does the trick if installed.
  • I found the issue and it was a mechanical issue that I was unaware of. Thank you for the help I'll keep in mind what you said for future problems.
  • As for the checksum errors I get that I now believe are unrelated to my initial question. I just captured this screenshot that portrays what I see every so often.
  • You need to activate logging and provide a log for correct analysis. But it is surely much too often you get the message. What is your input buffer length you entered? From the values I have the feeling it is rather low - try 127 byte.
  • it's funny you say that because it already is 127 byte. Communication timeout is at 3 seconds. I have logging enabled but don't currently have a log saved with this issue in it so I'll post it here when it happens again. Thanks for all the help.
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