Thermistor reads 50 Degrees C but Hot End At 100 C

[elqisqeyano]

What could this be?

[Polygonhell]

What could this be?

Bad wiring, damaged input, wrong thermistor selected in the firmware, bad thermistor any or all of them.
Unplug the thermistor at room temperature check the resistance it should be ~100KOhms
Does it read correctly at room temperature?
Does the reading change when the temperature increases?

[elqisqeyano]

What could this be?

Bad wiring, damaged input, wrong thermistor selected in the firmware, bad thermistor any or all of them.
Unplug the thermistor at room temperature check the resistance it should be ~100KOhms
Does it read correctly at room temperature?
Does the reading change when the temperature increases?

I installed one of the new heater cartridges. Is there a setting for them? It's a 12V 40W heater cartridge. Or maybe from when my hot end PEEK cracked. I took the hot end apart and off the machine, left the wires bare till I recieved the new one. I put together today and instead of using the resistors from seemecnc I used the cartridge.

[elqisqeyano]

What could this be?

Bad wiring, damaged input, wrong thermistor selected in the firmware, bad thermistor any or all of them.
Unplug the thermistor at room temperature check the resistance it should be ~100KOhms
Does it read correctly at room temperature?
Does the reading change when the temperature increases?

The thermistor Ohms are at 60 right now, but it keeps rising as the temp gets lower. seems to be working properly.

[elqisqeyano]

What could this be?

Bad wiring, damaged input, wrong thermistor selected in the firmware, bad thermistor any or all of them.
Unplug the thermistor at room temperature check the resistance it should be ~100KOhms
Does it read correctly at room temperature?
Does the reading change when the temperature increases?

When using heater cartridges you must select #6 EPCOS 100K thermistor. It's working with that setting, all others don't work with heater cartridge.

[Flateric]

This is sounding ysmptomatic of a damaged thermistor input port. Try two things, take and plug the thermistor lead from the heated bed into the thermistor hotend input and the hot end into the bed input.

Is the incorrect value still displayed for the now heated bed thermistor running into the hotend port?

Is the hotend thermistor giving a correct reading in the bed input?

Are both readigs correct or both icorrect?

I'll keep an eye for your answer and we can go from there.

[elqisqeyano]

This is sounding ysmptomatic of a damaged thermistor input port. Try two things, take and plug the thermistor lead from the heated bed into the thermistor hotend input and the hot end into the bed input.

Is the incorrect value still displayed for the now heated bed thermistor running into the hotend port?

Is the hotend thermistor giving a correct reading in the bed input?

Are both readigs correct or both icorrect?

I'll keep an eye for your answer and we can go from there.

Current setting with hot end in T0 slot Bed in T2 slot. At ambient temp hot end reads 000/000 Bed reads 022/000. When I switch them, put hot end in T2 slot and Bed in T0 slot , I get 000/000 in T0 slot and 022/000 in T2 slot. so when I put hot end in the Bed slot (T2) it reads hot end ambient, doesn't read ambient from T0. So it must be an input failure?

[elqisqeyano]

I can still print with hot end in T0 and Bed in T2 slots. Just the temp reading from T0 slot for Hot End is way off, by like 15 degrees, I have a temp probe attached the hot end so I can keep track of true temp and display temp. So I set slic3r to 205 and it gives me a true 225. It does read the temp of the hot end in T0 once the unit gets hot, T0 is reading but not as accurate as before, it also lags and stays behind the heated cartridge. Heated cartridge seems to heat up much faster than the thermistor is reading.

[elqisqeyano]

When I try to do a PID tune I get "PID Autotune Fail! Temperature too high" Even though the unit has been off all night.

[Flateric]

Ok, the only thing left to try is to attempt to use the other 2 available channels.

This is unlikely to work, but may be possible.

Do you know how to re-assign the pin designations in the firmware you are using?

Which firmware are you running BTW?

[elqisqeyano]

Ok, the only thing left to try is to attempt to use the other 2 available channels.

This is unlikely to work, but may be possible.

Do you know how to re-assign the pin designations in the firmware you are using?

Which firmware are you running BTW?

I do not know how to re-assign the pin designation in my firmware. I use Marlin firmware with Arduino. Is it in the Configuration.h tab? I would like to use T1 to read the temp instead of T0, which appears to be bad.

[Flateric]

I'm hoping someone will chime in here that knows your firmware because I have zero experience with it.

I'll have a poke at it later today after I get a moment to myself though.

[elqisqeyano]

Ok, the only thing left to try is to attempt to use the other 2 available channels.

This is unlikely to work, but may be possible.

Do you know how to re-assign the pin designations in the firmware you are using?

Which firmware are you running BTW?

Marlin firmware with arduino.

[elqisqeyano]

Can someone chime in here please? I need help setting hot end thermistor to read from the T1 on Rambo. I think T0 is burned out.

[jbenuck]

I made some progress here today that will hopefully help.

To use T1 for your thermistor, modify pins.h. Look for the section that says "#if MOTHERBOARD == 301". In that section, you will find variables named TEMP_0_PIN and TEMP_1_PIN. Change the setting of TEMP_1_PIN to -1 and TEMP_0_PIN to 1. That will change your board to use T1 instead of T0 for your hot end thermistor. Save and upload the firmware for the changes to take effect. I usually manually run the M105 gcode after uploading to see the difference.

You may find, as I did, that T1 is also blown. If so, try setting HEATER_1_PIN to -1 and TEMP_0_PIN to 7. That will cause the board to use T3 instead of T0 for the thermistor.

Here's what my current setup looks like. I should note that I have not testing this while printing. My thermistor arrives tomorrow. So far all I have done is use M105 to determine that I am getting reasonable readings for my remaining good thermistor when I plug it into the T2 and T3 ports.

Code: Select all

#define HEATER_0_PIN  9
#define TEMP_0_PIN 7 // was 0

#define HEATER_1_PIN -1 // was 7
#define TEMP_1_PIN 2 // was 1

Good luck and let me know how this works out for you (if you haven't already come up with an alternate solution).

-Joshua.

[elqisqeyano]

I made some progress here today that will hopefully help.

To use T1 for your thermistor, modify pins.h. Look for the section that says "#if MOTHERBOARD == 301". In that section, you will find variables named TEMP_0_PIN and TEMP_1_PIN. Change the setting of TEMP_1_PIN to -1 and TEMP_0_PIN to 1. That will change your board to use T1 instead of T0 for your hot end thermistor. Save and upload the firmware for the changes to take effect. I usually manually run the M105 gcode after uploading to see the difference.

You may find, as I did, that T1 is also blown. If so, try setting HEATER_1_PIN to -1 and TEMP_0_PIN to 7. That will cause the board to use T3 instead of T0 for the thermistor.

Here's what my current setup looks like. I should note that I have not testing this while printing. My thermistor arrives tomorrow. So far all I have done is use M105 to determine that I am getting reasonable readings for my remaining good thermistor when I plug it into the T2 and T3 ports.

Code: Select all

#define HEATER_0_PIN  9
#define TEMP_0_PIN 7 // was 0

#define HEATER_1_PIN -1 // was 7
#define TEMP_1_PIN 2 // was 1

Good luck and let me know how this works out for you (if you haven't already come up with an alternate solution).

-Joshua.

Thank you. I was able to make the switch and it works good. Now I can see my temps.