"Killed" on the LCD!?

[aodhan]

So, yesterday I had a problem while doing a test print wear a half hour into the print both thermistors went to DEF. The print kept going, unfortunately, even though there was no heat to the hot end. Upon cycling the power the thermistors immediately came back. So I went along to print another sample print to see if I would have the same error and to start trending issues since I'm new at printing.

This morning I set my printer bed heat to 90 manually and the hot end heat to 235 manually so that it could come up to temperature before I probed and did another test print.

After leaving the room for about 15 minutes allowing it to heat I came back to the LCD panel saying "killed". Everything seem to be functioning except for the heat. Again, the heat cut off just like when the thermistors went to DEF. I ran the probing code and it tapped the center, went to the Y tower and then froze. LCD panel unresponsive. Reset button did not work. I had to cycle power at the power supply.

Any ideas? Anyone see this at all?

[lightninjay]

The key to your "Killed" message is just a safety feature for if your printer is left heating unattended for too long, and the timeout for this feature can be changed within the firmware settings.

It is basically a "Did I leave the oven on?" fail-safe.

As far as the probing command failing, I do not know what to say. I am running a Rostock Max V2 without the auto-calibration, so I have no bearing.

I have however experienced times where my printer will lock up after cancelling prints, requiring a reset of the printer, but I usually just chalk that up to needing to clear the limited avilable memory of the RAMBo.

Also, as I mentioned, I do not have a probe of my own, but I thought I remembered reading that probing is supposed to be done cold? If I am wrong about that due to recent discoveries, my apologies.

[aodhan]

Thanks for the explanation on the "killed" message.

How do you clear the Rambo memory?

I wanted to hear someone elaborate more on when and why to probe. It would seem to me that you'd want your bed and head to be in the heated state so that any expansion is compensated for, but I could be wrong. Maybe I don't understand the real purpose of probing?

Anyone out there have some specific knowledge on this?

[Xenocrates]

How do you clear the Rambo memory?

Power cycle the printer. All the memory that gets consumed as the printer operates (With the exception of a small number of fixed length EEPROM values updating), is in RAM, and thus volatile.

I wanted to hear someone elaborate more on when and why to probe. It would seem to me that you'd want your bed and head to be in the heated state so that any expansion is compensated for, but I could be wrong. Maybe I don't understand the real purpose of probing?

Anyone out there have some specific knowledge on this?

Why: To calibrate the firmware model to the mechanics of the printer, so as to align the notional (used in the firmware calculations) values with the actual machine as built ones. This should compensate for slight construction defects. It appears that an overly large tower offset or a soft bed surface can cause some issues for the calibration model, and it doesn't correct for tower lean or rotation if those are improper (Luckily those should be pretty easy to get solid).

When: This is pretty subjective. The Lulzbot machines I work with calibrate with every print, and it's easy to see the downsides (At least with their method), as the calibrations aren't especially consistent. I've seen major changes in first layer thickness on the same printer in between two runs of the same G-code with nothing else printed in the middle. Mike (MHackney) also runs his FSR based Duet calibration with every print, but from what I understand FSRs are more consistent than the lulzbot continuity based sensor approach. I recomend not probing unless hardware has changed or been removed and replaced (IE, hotend or carriages changed, bed removed and remounted), or unless you get a bad print.

Why cold: The accelormeter based probe is unfortunately sensitive to EMF. This makes it very difficult to register a probe with the heaters running. The Bed especially, as it is a large volume that has a large current running through it (Especially on 24V). If the accelormeter PCB was shielded, it would be more possible. However, a set of shielded cables would be needed to keep the I2C signal clean as well. There is an offset built into the EEPROM values to theoretically compensate for the thermal expansion, and it does seem to work.

[aodhan]

Thanks for the detail, Xenocrates. That's very helpful for a mind like mine that needs to know "the why".

I started thinking more particularly about the "killed" scenario. What prevents the printer from cutting power in a circumstance where the bed reaches a thermal equilibrium and the amount of power in is required to just maintain a temperature. Is this the physical manifestation of the bed's effective max temperature and the software won't let you use any temperature that requires the bed heat to stay on continuously? I'd be bummed if 90 was above my bed's max temperature when the advertising material says the bed's max temp is 110.

Thoughts?

[Xenocrates]

Thanks for the detail, Xenocrates. That's very helpful for a mind like mine that needs to know "the why".

I started thinking more particularly about the "killed" scenario. What prevents the printer from cutting power in a circumstance where the bed reaches a thermal equilibrium and the amount of power in is required to just maintain a temperature. Is this the physical manifestation of the bed's effective max temperature and the software won't let you use any temperature that requires the bed heat to stay on continuously? I'd be bummed if 90 was above my bed's max temperature when the advertising material says the bed's max temp is 110.

Thoughts?

You can A) Increase the firmware timeout, B), twiddle the knob. Killed is only when it is heating to targets without a print job or user interaction. For example, mine has spent 4 hours heating to target when given a print job (It was really cold that day, and i just left it to warm up), and if you are actually working with it by touching the encoder and twisting or clicking it, it will happily continue to function. Timer based only.

Now, depending on the surrounding temperature, the bed can have some issues with 110C (Measured, but not calibrated). I find that if you keep it above ~25C environmental temp (According to startup temps and the laser cooler in the corner), it will eventually reach 100C, but I've not needed to go to 110C so far. You can slightly increase the available power by increasing the bed PID drive Max in the EEPROM, but be aware that may slowly broil the fuse on the rambo, as it would be continuous duty at more than 70% of the fuse rating. So you are correct that out of the box, the bed drive is capped. But it's not the killed doing it (And I don't suggest messing with that too much, honestly).

[geneb]

It will also say "Killed" if the printer has sat idle for a long enough period of time after the last movement command was received.

g.

[stough]

Yeah, I see the "killed" message on over night prints that completed successfully. Glad to know the origin.

-Tim