Hotend temperature and heating issue

Hi all,

back online after a long time, my Ormerod v1 was operating perfectly till a few weeks ago. It's a standard machine with dc42's IR differential sensor. Now the reported temperature for the hotend is always false :
- 32°C when "cold". The room temperature is actually between 10°C and 16°C (it's a veranda without heaters).
- when heating the hotend, for example requesting 100°C, the reported temperature raises very fast until ~100°C, within a few seconds. But the hotend doesn't actually heats, which looks normal to me as the sensor reports the required temperature and thus the firmware stops heating.
- if the thermistor is disconnected, the reported temperature is between 9 and 10°C, the fan starts and the hotend heats up to ~50°C

What did I try to fix it :
- totally decommissioned and recommissioned the IR differential board, the hotend and the sensor
- checked all the connectors and the connectivities, both visually and with a multimeter.
- replaced the thermistor with a 100k resistor : the loom is ok, but the reading using both Pronterface or the HTTP GUI reports a temperature ~39°C
- changed the thermistor with a new one, exact same model.

I'm now totally stuck, the only part I couldn't check further is the Duet board. Now I'm afraid that some port of the Atmel has been damaged, thus the bad temperature reporting.

Does anybody has any idea to investigate more, or, even better, to fix it ?

Thanks
Patrice

Have you updated the firmware, or changed config.g recently?

To me the symptoms sound like you've got a 4.7k board , but M305 isn't set to reflect this.

Quote
linked webpage
If you have a 4.7K board, and don’t make this change, your temperatures will report very high at room temperature on both the hot end and heated bed, and will over-read at the target temperature

Thanks for your answer.
Nothing changed in config.g for months, not to say years. My Duet is a 1k version, I've done the checks from your link and both resistors are marked 01b. The bed temperature is reported as expected, no issue with it. Anyhow I'll check it again tomorrow night.

Very odd.

Thoughts:

• If M305 isn't set, perhaps try setting it to force it to the correct value?
• Whilst this Duet wasn't made by the current producers, a post on the Duet forums could be an idea.

(dc42 was an Ormerod 1 owner back in the day, and is an all-round helpful chap in my experience. Your original post may yield better results than can be provided here Although saying that, he does pop his head in here occasionally)

I re-checked everything, including the resistors value. They are 1k. I tried to force the values with M305, not better.
When I require the hotend to heat say to 190°C, the read and displayed temperature raises from 40°C (the "cold" temperature of the hotend is 17°C, read with a laser thermometer) up to 195°C in less than 10s whilst the actual temperature of the hotend raises up to 20°C. The orange led on the IR board switches on until the sensed temperature reaches 190°C, the fan starts when the displayed temperature is over 45/50°C. I tried to remove the heating cartridge from the hotend, it becomes quickly very hot and red, so I assume it does work.

I do think that the analog port on the Atmel where the sensor is connected is dead. Is there any other port I could connect the sensor, the one for a second sensor for example ? Then I could either "swap" P1 and P2, I think I've seen some G code to do that, or configure Slic3r to generate G-code for P2.

Suggestions:

1. Send M305 P1 without parameters. Check that the reported values are the correct ones as set in config.g.

2. To rule out a problem with the hot end fan/IR board, try connecting the 100k resistor directly to the Duet, with the cable from the hot end disconnected. You could also try some other resistor values, for example 10k and 1k. If those resistors give the wrong readings then it confirms a problem with the Duet, most likely with the processor.

There are several temperature sense pins on the expansion connector that you could use instead. You would need to connect a 4k7 resistor between the pin and +3.3V.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi David,

Quote
dc42
1. Send M305 P1 without parameters. Check that the reported values are the correct ones as set in config.g.

Already done, the reported values are the correct ones.

Quote
dc42
2. To rule out a problem with the hot end fan/IR board, try connecting the 100k resistor directly to the Duet, with the cable from the hot end disconnected. You could also try some other resistor values, for example 10k and 1k. If those resistors give the wrong readings then it confirms a problem with the Duet, most likely with the processor.

Already done, with the 100k resistor connected in place of the thermistor to check the loom, then directly to the Duet. I also tried with various resistor values and checked against some resistance/temperature table I found in the troubleshooting documentation, the reported temperatures are always odd.

Quote
dc42
There are several temperature sense pins on the expansion connector that you could use instead. You would need to connect a 4k7 resistor between the pin and +3.3V.

Can you tell me which pin(s) I can use, please ? Regarding the 4k7 resistor, I suppose it is a pull-up one ?

Thanks
Patrice

Have you managed to resolve this issue yet?

Hi,

I've been very busy on various other tasks so still didn't completely fixed it.

I decided to switch to a MKS Sbase, much cheaper than a new Duet board. After buying it I discovered some information about MKS attitude regarding the Smoothie community and would have probably chosen not to buy this one but a true Smoothieboard, but in those times the price was important for me.
As the switch to a totally different board was like building a new printer, I decided at the same time to change the hotend for an E3D v6. Although dc42's IR sensor was perfectly reliable with the original Ormerod, it wasn't anymore with the MKS so I decided to move to BLtouch (an original one, not a copy).
For the moment I still face issues with the extrusion density, mainly layer delamination. I'm working on the following elements :
- I need to change many elements in the Slic3r configuration to suit the new hotend (temperatures, layer heights, speeds, ...)
- the X carriage is now 5-year old and is getting loose, thus the pressure is applied equally depending on the height and the speed
- the levelling has been very difficult to stabilize, now I'm doing it manually until I redesign the X-carriage for a more regular pressure and the ability to suit for both E3D and BLtouch.

By the way I'm working in the same time on a Tronxy X5S-2E which needs a lot a work to be reliable :
- like nearly all the 3D printers it isn't rigid enough, this lack of rigidity being a major flaw due to its belt path (H-bot). Much improved with corner brackets.
- the bed is moved with 2 Z motors, but I'll probably move to a single motor solution to ensure that a pression on a side of the bed won't break the levelling.
- the initial hotend is a bad copy of the E3D Cyclops (two filaments merged in a single Y chanel with a single heater), which implied to retract the filament by 2cm (yes, centimeters), before switching from a color to the other one, and frequent obstructions. I'll change it for a Chimera (two channels, two heaters).
- the H-bot path of the belt is somewhat puzzling at first time, but needs a lot of rigidity of both the frame and the belt. I changed it for a steel-reinforced belt.
- the original mainboard is a proprietary one, with a proprietary firmware, it can't accept an auto-levelling sensor :-( I changed it for an MKS Sbase to use the same board as for the Ormerod, but it should have been a true Smoothieboard if I'd knew about MKS.
- as for the Ormerod, a lot of job to do with Slic3r or Cura. For the moment I go on with Slic3r that I know quite well.

If somebody is interested, I can give some news each time I pass a stage, for both the Ormerod and/or the X5S.

Patrice

Thank you for your feedback Patrice.

Sounds like you have a massive load on your plate and I wish you the best of luck and time in order to manage completing it.

I am so glad that my Ormerod is still soldiering on quite nicely. But without all the aluminium upgrades I would have never gotten as far as I did. O yes and also the awesome support from all you fine folks here at the Ormerod forum.

I am currently busy completing my Root3 CNC build and have printed about 3Kg of ABS and 1Kg of PLA in order to have the parts for the machine.
Busy soring out Electronics now and the mechanical build is about 99% complete.

I would be well interested in your progress and also some pictures of the machines that keep you busy.

Good luck
Michiel