MINTEMP error at first startup

I recently received my new Materia 101 printer.
In the last two days I built it completely and I’m pretty sure there should be no big mistakes.
Today I uploaded the marlin firmware and turned it on for the first time.
The first thing I saw on the screen was gibberish, but after a few seconds I could read what was written on it.
It is like:

0/0°
X 0 Y 0 Z 000.00
Fr 100% SD—% o–:–
Err: MINTEMP

The problem I’m now facing is this MINTEMP error you can see.
Also, the temperature shown at the top of the screen is 0°, shouldn’t it be the room temperature?

Additional info:
-When turning the printer on the fan on the bottom (the one for electronics) turns on
-I can move all motors manually via the Prepare->Move axis menu, the extruder stepper too

Do you have any ideas?
I really hope to get some reply soon, I don’t want to have a nonworking printer for long if possible.

dp_1

A little update: I solved the gibberish screen problem by pressing the encoder near the screen (the one used to open the menu) when the printer starts, so it isn't a problem anymore. I'm still receiving the MINTEMP error, so any help is greatly appreciated! Even if you have an idea but are not sure if it works, please write it!

dp_1

I’m getting the same MINTEMP error. However, I only get it when the x axis is trying to move. That is it.

HI, I had a similar issue with my printer. the LCD read gibberish and then I would press the encoder and it would resolve itself. Now the LCD has stopped working altogether. I tried some mysterious combination or resetting, powering down and reloading firmware and got it to work again, once, but now I can't remember what I did and it had blanked out again. The LCD will light up and it does make sounds when I press the encoder but it doesn't display any text so I can't get it to run through the set up protocols. I hope the board is not burned out. any ideas?

Hi all,

On my first try after assembling my printer I had problem with the LCD display. There was some strange chars at the begining and after that, I had the MINTEMP error.

Well, the problem with the LCD display was a bad contact between the Arduino board and the Pololu shield. Make sure of attaching the pin header deeply. After that, I had no problem with LCD but I continued having MINTEMP error.

The problem related to MINTEMP was a bad contact in extruder connector. I noticed that because when I touched the cables and I powered on the printer, sometimes MINTEMP didn't appear.

To fix that, I removed the connector and I soldered the cables directly (see image)

Best regards, Jose.

ja_hurtado: Hi all,

On my first try after assembling my printer I had problem with the LCD display. There was some strange chars at the begining and after that, I had the MINTEMP error.

Well, the problem with the LCD display was a bad contact between the Arduino board and the Pololu shield. Make sure of attaching the pin header deeply. After that, I had no problem with LCD but I continued having MINTEMP error.

The problem related to MINTEMP was a bad contact in extruder connector. I noticed that because when I touched the cables and I powered on the printer, sometimes MINTEMP didn't appear.

To fix that, I removed the connector and I soldered the cables directly (see image)

Best regards, Jose.

My problem is that I can read the temperature using a custom circuit like this:

+5v | Thermistor | |___ To arduino analog pin A0 | 100K resistor | GND

This works with both the Mega 2560 shipped with the printer and a UNO board I have. So I really think that the connector/wire is fully working. But when reading it through the ramps board connector (e.g. by inserting the thermistor cable in T0) I receive the MINTEMP error. Can it be some broken trace or bricked capacitor on the ramps board?

dp_1

Did you check the RAMPS connections with a multimeter?

RAMPS Schematic RAMPS top

Perhaps the resistor R7 or the capacitor C5 are is a little bit unsoldered, or even the header pin. If you tested the thermistor circuit you are really close to the solution!

Regards, Jose.

Another thing that you can do it is trying to use the T1 pins for reading the temperature. I think it is easy. You can edit the source file "pins.h" to change the pin used for reading the thermistor.

  #define TEMP_0_PIN         15 // change to 14
...
  #define TEMP_1_PIN         14 // change to 15

I didn't test it, but it should work :)

I noticed TEMP_0_PIN was defined as 1 in my firmware (downloaded from the materia 101 home page and unmodified), not 15. Is this normal or I have to download another firmware? Where did you download yours from?

Thanks, dp_1

Ok. I think I got confused with the pin number because in pins.h there are definitions for more boards. As you can see in RAMPS schematic, the pin for sensor 0 should be 13.

You can browse the file "pins.h" here and it should be similar to the pins.h included in the original Materia101 Firmware

If I am not wrong, the board number is MOTHERBOARD = 34 and the proper code lines are 639 and 640. But perhaps, somebody of the Materia101 staff should confirm this.

Sorry, my fault. I read the first occurrence of the value, for a different mainboard. Under mainboard 34 the pins are right. I noticed that also the second thermistor and heated bed thermistor are enabled, so I tried disabling them. When disabling all sensors, I got a MAXTEMP error, with a temperature going over 300 degrees celsius. Then I enabled only the one I'm using, TEMP_0_PIN, and with all values (13, 14 & 15) it didn't work. I'm kinda lost now...

Ok. Let try this:

  1. Restore the original firmware.
  2. Swap the TEMP_0_PIN and TEMP_1_PIN: at line 639 modify the code to this:
  #define TEMP_0_PIN         15   // ANALOG NUMBERING
  #define TEMP_1_PIN         13   // ANALOG NUMBERING
  1. Connect the Thermistor in T2 position (instead of T0). T2 position is at the order side of the same pin array.
  2. Flash the firmware and cross your fingers :)

BeastFriend: HI, I had a similar issue with my printer. the LCD read gibberish and then I would press the encoder and it would resolve itself. Now the LCD has stopped working altogether. I tried some mysterious combination or resetting, powering down and reloading firmware and got it to work again, once, but now I can't remember what I did and it had blanked out again. The LCD will light up and it does make sounds when I press the encoder but it doesn't display any text so I can't get it to run through the set up protocols. I hope the board is not burned out. any ideas?

I made a issue of this on the GIT

Link: https://github.com/Sharebot3D/Materia101/issues/6

Can someone tell me if the swapping of pins helped solving the MINTEMP Error? Txs

Ok, I fixed MINTEMP Error by checking the connections. Txs anyway

Most of the time the issue min temp is a bad connection.

If your unlucky the bad connection might be on the pcb, but it is unlikely.

A little update: I'm now going to receive the new ramps board as mine was broken. In the meantime, I tested a bit more, reproducing the ramps thermistor circuit and marlin code on an arduino uno. This way there was nothing from the printer circuit, so nothing could go wrong. I used a fixed resistance of about 110k ohm (3 x 330kohm resistors in parallel) as the thermistor and I could read a value of about 24 degrees. Then I connected to the printer thermistor instead of the dummy one I made, and I could read a value really near the ambient temperature (21-22 degrees celsius). If you want I can post a schematic of the circuit I used, so that if somebody else has the same problem he/she can check if it's the board or not.

I know, this may seem redundant, but I just wanteed to check if it really was the board being faulty or something else :).

dp_1

That would be great! Sharing knowledge is great!

Alright then, this is what I used for testing the thermistor.
I used another arduino just to be sure, you could probably use the printer one if it isn’t broken. The schematic is attached, just connect the wire marked as “READ” to pin A0 of your Arduino board. The sketch I used is attached too, it is mostly taken from Marlin firmware.
In the schematic I used R2 for the thermistor, you can either use the real thermistor (right way) or a fixed resistance (why??? - the schematic and code are already tested :slight_smile: ).
To use it, upload to the board and open the serial monitor, you’ll read something like (values are fake, I don’t remember them):

START
RAW: 560
TEMP: 54

RAW: 540
TEMP: 98

Raw values are simply read from the ADC, so they range from 0 to 1023, and temperature values are in celsius degrees.

This is mostly a copy-and-paste work, as the schematic is taken from the RAMPS board and the code is adapted from Marlin firmware.
If you need anything else feel free to ask, I’m more than happy to help :).

circuit.png

read_thermistor.ino (4.14 KB)

Oh. here is a pins.h with the pins switch if anybody else want to troubleshoot their shield: https://drive.google.com/file/d/0B2bqiaE1rzP7akNja3VhU2lQOTAtVlBLSWl4blJraUNEUDRF/view?usp=sharing