HotBed Heating Too Slow?

A Former User

@techmav thanks for the treatise on PID turning.

Ah, what does PID stand for?

I have zero experience with communicating via gcode. If fact, I don't like the idea of converting thoughts / language into code for the purposes of communicating. On the other hand, I recognize that using code to lump a bunch of ideas together works. But a long doc full of code-speak, none of which says "this is how you actually do this," well . . . that's rough. I get it that one needs to do this, but jeeze-louise, it's tough of noobies.

So here's what I know: at the top of DWC (I'm using code to shorten this up), there's this long line that starts with "Send code . . ., after which there's this blue box with an arrow pointing right, and the word: Send. Are you suggestion I type something into that box, and send it to my printer so it can do PID tuning? This is the stuff I'm missing in a lot of the advice and recommendations I'm getting. And because I don't get the fundamentals, the advice is lost on me. We're all wasting our time. What might be better? Someone saying, "Type the following into that line on the top of your DWC. Send what you typed to the board. Wait for the board to process the information. When it's done, look somewhere, and copy that information (somehow), and put it in your config.g file (somehow). That's what I'm getting from reading your wonderful, informative post, and skimming down the pages and pages you sent me (that you, by the way, that was very helpful long term).

Mac

A Former User

@jay_s_uk read a bunch of these posts, decided to give your striaght-forwards reply a shot. Thank you. Mac

TechMav

@mac

TL;DR

In the web interface, click on Console on the left.
Just below the grey boxes at the top, labeled Status, Tools, and Temperature Chart, there is a blank space with a blue box to the right that says "Send"
In that box, you will need to enter:
M303 H0 S60
and click Send. This will run the PID tuning cycle. It may take up to an hour.

Once it finishes, you will see an output below it with an M307 line in it, something like:
M307 H0 R0.579 K0.295:0.000 D2.99 E1.35 S1.00 B0
Copy from M307 to the B0 at the end.
On the left, click on System, then click on config.g. This will open the config file for the printer in an editor.
Find the line in the "Heaters" section that starts with M307. Replace that line with the line you copied.
Click Save at the upper right, and it will ask if you want to reload the motherboard or run the config. Either will work to apply the change.

Background info:
PID stands for proportional–integral–derivative. It's a control loop that takes into account (in this case) how fast the print bed heats up and cools down, so it can modulate the heating to keep it stable, rather than the 'bang-bang' approach which turns the heat full on or full off. PID tuning lets the system figure out what heating rates to expect instead of the default values that may not apply.
I was having the same issue, my print bed is a 12" x 12" x1/4" aluminum plate, and was heating at about 0.3C/second instead of the 1.7C/sec the system was expecting.

A Former User

@techmav thanks for coming back with that recipe for action. it's going to be the first time I edit my config.g file! Mac

A Former User

@mac process update: DWC cancelled the process because the temp wasn't reached (in an appropiate time?, DWC didn't say). So, can I S40? Because just before the cancel happened, the bed was as 43.9.

A Former User

@rushmere3d did that in a subsequent config.

Phaedrux

@mac said in HotBed Heating Too Slow?:

Ah, what does PID stand for?

proportional–integral–derivative

https://en.wikipedia.org/wiki/PID_controller

A Former User

@phaedrux there's got to be a joke in that acronym somewhere!

Phaedrux

I thought so too, and I could get close, but never quite reach it.

A Former User

@phaedrux I've never meant a proportional integral I didn't find derivative.

A Former User

@techmav

6/23/2022, 3:01:49 PM Warning: Auto tune of heater 0 failed due to bad curve fit (R=0.129 K=2.291:0.000 D=2.92)

A Former User

@jay_s_uk well, the tuning failed three times. so I've gone back and changed the profile to PID for the bed, and now we're going to see if that will help it pass DWC's tuning procedures.

Phaedrux

What command did you use to start the tuning?
Are you starting from ambient temp?
What does your heater temp graph look like during the process?
Do you have the correct thermistor values set for your sensor?

A Former User

@phaedrux thanks for asking, I've edited the config.g maybe a dozen times today.

M303 H0 S60. That test failed. I reduced the 60 to 40. That test failed. Then I reduced it to 16. I don't remember the message, but it sounded like something had gone very wrong.
Room temp's in the seventies.
The graph shows a line progressing to the right.
I didn't, but I continued to edit the config.g file to change that until I got something like an NTC 3950, which is as vanilla as the choices are, I think.

Anyways, when the last test crashed, I decided to work on changing the motors from being X and Y reversed to X and Y forwards, and Z reversed.

Which lead to:

I've got movement on all 3 axis. For X, the print heads goes up, then down about 2-3- inches when I home it. After that, I can move it to the right incrementally until it gets to the far right side of the printer. Getting it to come back is hit and miss, but mostly misses.

For Y, the bed goes towards the front when you click on Y-50 and towards the back when you click on Y+50. So I'm guessing I should reverse Y.

The printer has no idea where home is (far left is 0 for X, far back is 0 for Y, and 2.5mm above the bed is 0 for Z (because the BLTouch is working properly, but I haven't tweaked it's elevation yet).

Mark

A Former User

@mac I forgot two things.

I changed the voltage of all the motors to 600ma
I changed the steps to 32.

A Former User

@rushmere3d see the post above this one, there’s good news.

A Former User

https://youtube.com/shorts/HVZQz00e_HE?feature=share

This 40 second video on YouTube shows my printer X-homing, Y-homing, and Z-homing in that order.

droftarts

@mac definite progress with that video! A couple of things…

Is the back right corner of the bed the ‘origin’, ie X0 Y0, for you? This is okay (prints won’t be mirrored, but will be rotated 180 degrees), but usually the origin is when the nozzle is over front left. Or you can get fancy and set the centre as the origin.
Most printing starts in the middle of the bed, so it’s usually best to probe for Z in the middle of the bed, too.
Motor noise. The stepper drivers on the Mini 5+ support two stepping modes; stealthchop and spreadcycle. In stealthchop, the motors will be quieter, but have less torque, so there is a slightly higher chance of missed steps (usually only when moving fast and the nozzle hits something). Spreadcycle has more torque, but is noisier. There are various things you can do with these modes, but for now, trying sending in the console:

M569 P0.0 S0 D3
M569 P0.1 S0 D3              
M569 P0.2 S1 D3
M569 P0.3 S1 D3

Stealthchop is supposed to be the default for the drivers on the Mini 5+ in RRF 3.4, so this may not make a difference.

Ian

A Former User

@droftarts the home point for this Xvico was the FRONT, LEFT, Corner.

Did you watch the 40 second video (see link above?)?

When one Home's the X-axis, is it supposed to go up a few inches, then come back down a few inches?

Why is homing the x-axis telling the z-axis to go up and then down?

Mac / Mark / Corlissmedia (2.0)

A Former User

@droftarts Okay, in the Console, I sent all 4 of those commands. The printer responded by moving up and down, up and down, up and down, and then it tried to land on the bed, but the BLTouch told it to get off of me (I guess the BLTouch has been reading the New York Times over the last hour or so), so the print-head continued to climb until I turned the printer off to keep it from pounding against the top rail.

Mark