"Board error, extruder switched off"

Topics around mechanical design, controller and electronics. Mods & hacks welcome.
wermy
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Joined: Fri Jan 20, 2017 1:49 am

"Board error, extruder switched off"

Postby wermy » Thu Oct 05, 2017 12:29 pm

My N2 stopped printing and popped up that error on the screen. I restarted it and the error popped up again. I power cycled everything and the error went away, so I tried to heat up the nozzle a bit so I could remove it from the failed print. The nozzle heated very slowly and I eventually noticed a bit of smoke coming from somewhere around the hotend (obviously I cut power at this point and came here).
I also noticed the board on the extruder itself doesn't show any LED activity now... Is it possible that's all that has gone bad? Is that something covered under warranty (it's just less than a year old)? I've been using it every day for months and months without any issues.
Thanks.

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walshlg
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Re: "Board error, extruder switched off"

Postby walshlg » Thu Oct 05, 2017 12:57 pm

submit a help request ticket and tug on the hotend wires to make sure everything is intact

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Brandon
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Re: "Board error, extruder switched off"

Postby Brandon » Thu Oct 05, 2017 1:28 pm

We would like to help trouble shoot your issue. Could you please open a ticket in our system here:

http://help.raise3d.com/support/tickets/new

Jetguy
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Re: "Board error, extruder switched off"

Postby Jetguy » Thu Oct 05, 2017 3:26 pm

We have to raise awareness on this issue.
viewtopic.php?f=4&t=3524

I can tell you with 100% certainty that this is exactly what just happened. The user had a flakey ribbon cable connection. Could be the connectors or the ribbon cable itself failing from flexing. This allowed the printer to pass the power on test because the thermocouple amplifiers reported (cable was passing information at power on) and thus "charged up" the ADC pins the motion control board thermocouple inputs. However, motion or other failures, the ribbon cable became unplugged or otherwise disconnected and because of a "design function" (putting it nicely) of the motion control board, the hardware is completely unable to detect this ribbon cable connection failure after a power on state. This means that if the last reported temp was valid and the user commands a setpoint higher than the last reported temp, the heaters will turn on and since there is no actual working temperature feedback in this fault state, the heater will stay on and rise to an UNSAFE TEMPERATURE!! Again, what you have here is a fault that goes undetected, then coupled with user commands to heat in this fault state can and DOES and it proven and repeatable leading to an uncontrolled heater on state.

wermy
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Joined: Fri Jan 20, 2017 1:49 am

Re: "Board error, extruder switched off"

Postby wermy » Thu Oct 05, 2017 4:35 pm

Jetguy wrote:We have to raise awareness on this issue.
viewtopic.php?f=4&t=3524

I can tell you with 100% certainty that this is exactly what just happened. The user had a flakey ribbon cable connection. Could be the connectors or the ribbon cable itself failing from flexing. This allowed the printer to pass the power on test because the thermocouple amplifiers reported (cable was passing information at power on) and thus "charged up" the ADC pins the motion control board thermocouple inputs. However, motion or other failures, the ribbon cable became unplugged or otherwise disconnected and because of a "design function" (putting it nicely) of the motion control board, the hardware is completely unable to detect this ribbon cable connection failure after a power on state. This means that if the last reported temp was valid and the user commands a setpoint higher than the last reported temp, the heaters will turn on and since there is no actual working temperature feedback in this fault state, the heater will stay on and rise to an UNSAFE TEMPERATURE!! Again, what you have here is a fault that goes undetected, then coupled with user commands to heat in this fault state can and DOES and it proven and repeatable leading to an uncontrolled heater on state.


Thanks for the info, I'll take a look at this when I get home. There was part of the error that popped up that said "MAX_TEMP" something something. I should have taken a picture. I did try to dump the logs but it only seemed to have logs since I restarted it last.

This is kind of scary. I assume, then, that my extruder got ridiculously/unsafely hot at some point. Does that typically result in permanent damage to the hotend?

Jetguy
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Re: "Board error, extruder switched off"

Postby Jetguy » Thu Oct 05, 2017 5:08 pm

It doesn't mean 100% that there was damage but there is likelihood that by the time you see smoke, the filament inside has burned and likely could lead to a nozzle jam later. It might take using some cleaning filament or other methods- maybe even changing the nozzle in extreme cases. Another fact, the aluminum can deform long before it melts. This means the weak spot is the threaded block to the throat tube connection- if you overheat an extruder, this is the most likely place to fail later. Basically what could happen is, you change the nozzle, while tightening the nozzle it mates to the throat tube pushing it up, this damages the weakened threads, now your hotend leaks. I'm not saying this did happen, I'm saying it could happen. Aluminum alloys melt before they ever glow red and they deform long before they melt.

Jetguy
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Re: "Board error, extruder switched off"

Postby Jetguy » Thu Oct 05, 2017 5:43 pm

Again, hopefully, you caught it before it got extremely hot. Since the root cause was the controller had no idea what the real temperature was, we have no idea how hot it got. Maybe the log says something if somehow the wiring for a brief second made contact and at least one time the real actual temperature was reported.

The lessons learned should be:
Everyone check your ribbon cable for proper seating in the connector at the extruder head breakout.
Take steps and measures to prevent it from coming unplugged. Everything from hot glue to zip ties, maybe even printed clips.
If you have a temperature fault- inspect and find out why. Don't just assume it's a glitch and print if you didn't change or fix anything and it goes away. This is exactly how you the user falls into the trap.
Strongly consider raising support tickets and if Raise 3D cannot provide resolution soon on this issue, consider making the safety modifications I have outlined and a few people other than me have tried and tested and proven. Again, Raise 3D should be addressing this, but the community has taken the extra steps and identified and engineered solutions right now today.
If have a temperature fault, you test it, you cannot figure out why, it seems ok, DO MORE careful testing. Do not assume all is OK and just haul off and print more. Suggestions include setting the temperature to a low temp like 50C, watching the temperature rise and stabilize at 50C while ALSO monitoring the actual heater temp using an external sensor of some type. If it heats slowly, if you see smoke, immediately be prepared to power off. These are the only warning signs you get and they may be subtle. If you aren't even looking for them- that's where this goes from bad to really bad. Again, temperature faults are telling you there is a problem. Don't ignore them and assume just because "it went away" that the printer is operating correctly and SAFELY. Again, the key is that a testing procedure and safety warning needs added to the FAQ and instructions. Users need told up front that they need to take error messages seriously. They also need told more of what to do and "just rebooting and seeing if it goes away" is not the proper answer in light of all that has been uncovered.

This whole scenario is unfortunate, but again, education and training and documentation could save a lot of owner and users some problems.

wermy
Posts: 28
Joined: Fri Jan 20, 2017 1:49 am

Re: "Board error, extruder switched off"

Postby wermy » Thu Oct 05, 2017 7:34 pm

Jetguy wrote:Again, hopefully, you caught it before it got extremely hot. Since the root cause was the controller had no idea what the real temperature was, we have no idea how hot it got. Maybe the log says something if somehow the wiring for a brief second made contact and at least one time the real actual temperature was reported.

The lessons learned should be:
Everyone check your ribbon cable for proper seating in the connector at the extruder head breakout.
Take steps and measures to prevent it from coming unplugged. Everything from hot glue to zip ties, maybe even printed clips.
If you have a temperature fault- inspect and find out why. Don't just assume it's a glitch and print if you didn't change or fix anything and it goes away. This is exactly how you the user falls into the trap.
Strongly consider raising support tickets and if Raise 3D cannot provide resolution soon on this issue, consider making the safety modifications I have outlined and a few people other than me have tried and tested and proven. Again, Raise 3D should be addressing this, but the community has taken the extra steps and identified and engineered solutions right now today.
If have a temperature fault, you test it, you cannot figure out why, it seems ok, DO MORE careful testing. Do not assume all is OK and just haul off and print more. Suggestions include setting the temperature to a low temp like 50C, watching the temperature rise and stabilize at 50C while ALSO monitoring the actual heater temp using an external sensor of some type. If it heats slowly, if you see smoke, immediately be prepared to power off. These are the only warning signs you get and they may be subtle. If you aren't even looking for them- that's where this goes from bad to really bad. Again, temperature faults are telling you there is a problem. Don't ignore them and assume just because "it went away" that the printer is operating correctly and SAFELY. Again, the key is that a testing procedure and safety warning needs added to the FAQ and instructions. Users need told up front that they need to take error messages seriously. They also need told more of what to do and "just rebooting and seeing if it goes away" is not the proper answer in light of all that has been uncovered.

This whole scenario is unfortunate, but again, education and training and documentation could save a lot of owner and users some problems.


Thanks again, I appreciate it. I intend to do the mod that you showed. You said a 1M resistor - does the wattage matter? I see you used 1/8 watt resistors but also indicated it was all you had on hand.

Sorry if I should be asking this in another thread - is there a dedicated thread for that particular mod? It seems like it deserves it, with the implications of people experiencing the issue I did.

Jetguy
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Joined: Tue Mar 22, 2016 1:40 am

Re: "Board error, extruder switched off"

Postby Jetguy » Thu Oct 05, 2017 8:04 pm

Fair enough question on resistor size but it absolutely does not matter. A resistor is sized by how much heat energy it can safely dissipate. In this scenario, the amount of power turned to heat is so tiny you would have a tough time measuring it. I cannot express in a way you can visualize how tiny this amount of power is. This is why such a huge value resistor 1 mega ohm is used. The current and thus energy is just barely enough to make the pin change from it's steady state voltage and that's why this works without offsetting actual temperature reads when the system is working but also causes the system to trigger the instant the cable comes unplugged.

wermy
Posts: 28
Joined: Fri Jan 20, 2017 1:49 am

Re: "Board error, extruder switched off"

Postby wermy » Thu Oct 05, 2017 10:58 pm

Jetguy wrote:Fair enough question on resistor size but it absolutely does not matter. A resistor is sized by how much heat energy it can safely dissipate. In this scenario, the amount of power turned to heat is so tiny you would have a tough time measuring it. I cannot express in a way you can visualize how tiny this amount of power is. This is why such a huge value resistor 1 mega ohm is used. The current and thus energy is just barely enough to make the pin change from it's steady state voltage and that's why this works without offsetting actual temperature reads when the system is working but also causes the system to trigger the instant the cable comes unplugged.


Thanks. And good call: I checked when I got home and sure enough the ribbon cable was loose. Wow. That's a scary design flaw. I picked up a couple 1M resistors and will be doing that modification asap. Thanks again.

wermy
Posts: 28
Joined: Fri Jan 20, 2017 1:49 am

Re: "Board error, extruder switched off"

Postby wermy » Fri Oct 06, 2017 3:22 am

Okay, I modified my board as Jetguy instructed. Now if I unplug the connector, I immediately get the MAX_TEMP error with prompt to restart the printer. Also added a zip tie for good measure. :) Thanks again, Jetguy!


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