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Error:Heating failed, system stopped!

Posted: Mon Mar 05, 2018 2:10 am
by sprior
Anyone seen this one before? First time I've set the bed heat to 100C in a long time.

Recv: T:80.29 /0 B:85.70 /100 @:0 B@:127 W:?Recv: Error:Heating failed, system stopped! Heater_ID: bedChanging monitoring state from 'Printing' to 'Error: Heating failed, system stopped! Heater_ID: bed
'Recv: Error:Printer halted. kill() called!Recv: \x00\x00\x00\x00

Re: Error:Heating failed, system stopped!

Posted: Mon Mar 05, 2018 2:20 pm
by ednisley
sprior wrote:First time I've set the bed heat to 100C in a long time
And, most likely, it's the first time you've called for so much heat in a cold room.

The data dump suggests the heater ran out of grunt:

Code: Select all

T:80.29 /0 B:85.70 /100 @:0 B@:127 W:?
The B:85.70 /100 shows the bed is at 85.7 C, well below the 100 C setpoint.

The B@:127 shows the bed heater at 100% PWM. For obscure reasons, 127 means 100%.

When the heater can't reach the temperature setpoint within a "reasonable" amount of time, the firmware concludes either the thermistor or the heater has failed and shuts the printer off. You can change the timeout by tweaking the firmware, but it won't help when the heater simply can't produce enough heat.

Turning the bed fan off eliminates a strong cooling breeze across the glass and helps the heater. At least for the PETG I always use, printing without a fan doesn't change the print quality.

Putting the printer in a heated enclosure would definitely help, at least if you could keep the interior 25 C above ambient.

Or ... wait for summer! [grin]

Re: Error:Heating failed, system stopped!

Posted: Mon Mar 05, 2018 5:08 pm
by insta
This is a very good time to check for loose connections. The stock M2 bed @ 24v can hit 105C reasonably quickly in a chilly room (albeit one without drafts).

Re: Error:Heating failed, system stopped!

Posted: Mon Mar 05, 2018 6:25 pm
by ednisley
insta wrote:check for loose connections.
Ah, yes, the smell of charred plastic rising from the electronics box, back where nobody thinks to look.

Not so much of a problem with a 24 heater, but good to keep in mind.

Re: Error:Heating failed, system stopped!

Posted: Mon Mar 05, 2018 6:54 pm
by sprior
I had one of the original 24V heated beds which didn't have a great strain relief and just a few weeks ago replaced it with the newer version. I hadn't printed anything but PLA for at least a year and with some recent upgrades thought I'd give EPC a try, so this was the first time I was heating the new bed to over 60C and the first time for the machine in quite a while.

I just hope there isn't an issue with the new heated bed.

Re: Error:Heating failed, system stopped!

Posted: Mon Mar 05, 2018 7:26 pm
by insta
I've actually wondered about adding jumpers along the large 6-pin plug on the back. There were originally two sets of wires headed to it, back in the Rev A days (12/19v). With the 24v upgrade, we got 3 pairs of wires, with the internal bonding on the power supply and individually carried to the board. The heated bed will draw 10A or so, carried along some (relatively thin?) wires, while the remaining two pairs supply a total of about 4 amps between them. Bonding the positives together and negatives together at the RAMBo plug will have each set of wires carrying roughly 4 amps. It would be less voltage drop and may lead to a faster heat-up.

Re: Error:Heating failed, system stopped!

Posted: Sat Mar 10, 2018 9:30 pm
by sprior
Since the wiring was brought into question I opened the machine and did some digging. Unless it's really well hidden I didn't see any molten connectors or residue.

The machine is in my basement with no real drafts or air movement, but is about 60F. I also measured the resistance of my old/new beds. Both heaters were 4 ohms. The old thermister read 149.3 ohms while the new one read 143.9 - don't know if that's enough difference to be out of spec or require compensation.

Re: Error:Heating failed, system stopped!

Posted: Sun Mar 11, 2018 1:02 am
by ednisley
sprior wrote:Unless it's really well hidden
You unplugged all the connectors, peered inside both sides, then snugged all the screw terminals before plugging 'em back in?
is about 60F
60 F = 15 C, which sits on the chilly side of normal. I think the heater just doesn't dissipate enough power to get the platform temperature 85 C above ambient.

For a simple test, manually set the platform to 100 C and watch the temperature plot. If the heater has enough grunt, the plot should rise just about linearly, then go horizontal at 100 F as the firmware runs the heater in bang-bang control mode.

However, I expect you'll see the temperature rise rapidly at first, then gradually bend over as it approaches 85 C, with the heater continually running at 100% duty cycle. If that's so, then you need a (much) warmer room, a box around the printer, or a heater with Moah Powah.

You can increase the heater power by running it at a (somewhat) higher voltage, which is not to be done casually. You'll need a separate power supply (maybe 36 V, dialed back to the high 20s), a DC-DC solid-state relay to take the higher voltage off the RAMBo MOSFET, and some rewiring.