Various Questions from a Newb

[BacklashRC]

In the Repetier folder in the Github repository, there is a rostockv3.hex file. What is it for? The repetier.ino file is what the Rambo is populated with, using Arduino IDE.

Second, I notice that the firmware for the Rostock Max V3 was updated on Feb 1st, 2017, but see no notes on changes made. Is there somewhere that I can find out what changed, something like a revision history?

Third, the build manual provides instruction for calibrating the PIDs of the hot end, but says nothing about the PIDs for the bed. Is there a process for this, and if so, where can I find the steps? (My bed occasionally will drop ~15-20 degrees during a print, but not all of the time.)

Fourth, I am having one hell of a time getting my bed level calibration correct. Is there a procedure for adjusting the end stop screws on the V3, or is their position auto compensated for with the calibration cycle?

I appreciate the help in advance.

[djarmag]

Seems the bed does get auto adjust but you can reduce the offset of each plane by using just 3 clamps and ensuring the glass isn't being pressed down with the clamps

Here is what I read from another user regarding end stops. I haven't done this yet but I just fully screwed in all end stops and did a cal.

Once you have your V3 built and probing and printing here are a few things you can do to improve auto-calibration and reproducibility.

Tweak the carriage screws to get all three tower endstop offsets to within 4 steps/mm (or less). Travel is 80 steps/mm so 8 steps is 0.1 mm. The target 4 steps is 0.05mm. As you can see in the screenshot, mine are within 4 steps.
Screen Shot 2016-10-13 at 2.57.38 PM.png
Here's how you do it:

Calibrate to get your baseline. After you calibrate, look at the eeprom settings for the tower offsets as shown above. In OctoPi I use 2 plug ins that make this really easy: 1) EEPROM Repetier Editor Plugin and 2) Custom Control Editor. I created a custom button that runs the v3Probing.gcode script, making it really easy. Here's a screenshot on how to set that up:
Screen Shot 2016-10-13 at 3.05.19 PM.png
Once you have the control created, you need to put a copy of the script in: /home/pi/.octoprint/scripts/gcode/custom on your RasperryPi. The control automatically looks in the custom folder.

Ok, so you calibrate and then look at the eeprom settings using the EEPROM plugin. I've found that a 1/4 turn counterclockwise is about 7 steps. Start with your tower with the largest offset. Take the difference in the number of steps between the towers with the greatest values - so if Z was 21 and X was 8 and Y was 14 - the difference between Z and Y is 7. Simply turn the Z screw about 1/4 turn counterclockwise then re-run the auto-calibration and check again. Continue this process until you sneak up on <4 steps for all 3 towers. Note that you could also do the opposite of what I described above and increase the steps of the lowest tower value.

Once you get to a low step difference, run auto-calibration several times to check repeatability. If the steps change significantly from run to run, you likely have some sort of mechanical slop somewhere. Loose endstops, pulleys, steppers and belts are prime candidates. Hunt the problem down and fix it.

[Eric]

In the Repetier folder in the Github repository, there is a rostockv3.hex file. What is it for? The repetier.ino file is what the Rambo is populated with, using Arduino IDE.

No, the .ino is human-readable source code, as are the other files in the same directory as the .ino file. It gets compiled into a binary format, which are the low level instructions that actually execute on the arduino processor. That then gets saved in a .hex file, which is a human-readable hexadecimal dump of that binary. The .hex file is then used to send the binary to the Rambo. They're two distinct steps, even though the Arudino editor integrates them into one user button and mostly hides the process from you.

From the manufacturing point of view, it makes sense to save the pre-compiled binaries (the .hex files) to pre-load on their products (especially the ready-to-print ones), rather than running the compiler each and every time. There are command line tools that allow you to skip all the preliminaries and just load an existing .hex file to the product.

So far as end-users are concerned, the hex files can be ignored.

Second, I notice that the firmware for the Rostock Max V3 was updated on Feb 1st, 2017, but see no notes on changes made. Is there somewhere that I can find out what changed, something like a revision history?

Yes. In github, there's a history button up on one of the top bars that brings up a list of commits. Each item on the commit history is a link to what changed in various files for that commit (red lines were removed, green lines were added).

[BacklashRC]

Thanks, Djarmag. I will investigate the autocal improvement that you posted.

Eric, I found the history. Thank you!

[BacklashRC]

So I have made the endstop adjustments. X=0, Y=1, Z=3, but the unlevel bed remains unchanged.

I have also run the bed PID auto tune and the heating problem persists.