I am having consistent problems with this printer remembering its z calibration after it has been powered down. Almost every time I start it up and begin a print, the bed rises too high, pushes up on the X-axs carriage, and the nozzle scrapes the glass when it comes off the wiper. Each time, I have to go through the bed leveling procedure. Sometimes that works, and sometimes it results in the nozzle being a couple of millimeters above the glass after I store memory and restart the print. I have NO idea why this thing cannot function reliably after it has been powered down, and am becoming really frustrated. My delta, for all of its other faults, can power up after a month of being idle and still be bang on for z calibration. Either I am missing something obvious, or there is a fault here that I have not appreciated. So, if anyone can help me retain the hair I have left, I would really appreciate it.
I think you probably just need to save your settings. It's something mentioned during the calibration process. You can access it anytime via Control, Store Memory, or pushing M500 through a GCODE terminal. See if that helps. It should write your settings to EEPROM.
I store memory (from the Control submenu) every time. It just doesn't seem to take. The problem is, it's not consistently repeatable. I've had a few (very few) occasions when I start up and things are good. But, more often than not, Z is off. So then I either adjust the IR sensor and go through that whole routine, or I re-do the bed leveling routine. I store the memory (or at least I assume that I do, since there is no feedback other than a beep) and cross my fingers.
Your IR probe isn't hitting the wiper of the ooze bucket, by any chance, and getting knocked out of alignment? btw. there is NOT even a beep when you select "Store Memory", which is two menus up from where you just entered the new Z offset.
Sadly there is no "answer" when storing memory from the LCD. If you do an M500 from OctoPrint or another host then you will see a response... Be sure to store right after you did the levelling. Check your IR sensor as @R Design said... I have no other idea at the moment... Sorry...
It could be that the IR head is too far to the left when doing the autohome, and is sometimes reading the edge of the glass plate. You could adjust the X-axis endstop and do a new autohome. See if that works.
@Rob Heinzonly, looks like you might have the winning suggestion. Backing out the x-axis end stop screw seemed to fix the problem without my having to adjust the IR sensor. Thanks! Now let's hope it holds...
I had that problem for a while until I flashed my firmware, and then after that the eeprom storage worked. YMMV
Thought I would update this thread because I ran into the problem again today. Although I didn't opt for the Octopi upgrade, I have a Raspberry Pi that I used for the same purpose. Today, I disconnected it from the printer to add a longer camera cable. While it was disconnected, I turned on the printer and auto-homed it. Like before, the hotend carriage homed as usual, but the Z axis just kept going up until it drove the glass into the nozzles. I powered down, reconnected the Raspberry Pi, and this time the auto home behaved as expected. Thinking back, the last time I had this problem, the Octoprint was also disconnected. So my question is, what effect might Octoprint be having on the printer's homing behavior?
