ERR: MAX TEMP error on printer

Hi,

I just got myself my second 3d printer, a Prusa i3, which is awesome so far. I tried printing PLA with it, and besides some issues releated to settings it prints great.

However, when I was going to try to print some ABS, I got a MAX TEMP error. It seems to consistently trigger as I reach 235 degrees C. This leads me to believe that it's some firmware failsafe thing or whatnot, and I feel like I should be able to reconfigure this. My Prusa i3 has an LCD interface which allows me to check some of the settings of the machine, and I found a MINTEMP and MAXTEMP setting, but this was set to 250 degrees, so I don't really understand what's going on here.

I have a Prusa i3, with RAMPS electronics and a magma hot end...

change maxtemp to 270.

what may be happening is it overshoots when first warms up. then it shuts off. no way to heat up again unless reset.

other option if maxtemp at 270 does not work, then rewire the thermistor.

No, as I said, it triggers at 235, there is no overshoot. Both my computer and the LCD display reports the temperature to be exactly 235 when it shuts off. Somewhere in some code, 235 seems to be defined as some sort of limit and I can't find it. When I tried changing MAXTEMP to 270, it would only let me go as high as 220, even though it was previously 250. Didn't seem to matter though, it looks like it is just a submenu of something called autotemp, which is turned off anyway.

Does anyone know where this 235 limit comes from and how I can remove it?

I know it seems like the temp is stable, but it is showing up to a 16 sample average. only 1 temp out of range can shut down the printer. look at this line here in configuration.h if it is marlin firmware for example.

#define HEATER_0_MAXTEMP 275;// i think these are the defaults. since you said that you changed yours to 270, then something else is going on. what type of power supply are you using?

you can post your entire firmware file here and people can look at the code. the easiest thing to do would just be reload a new copy of firmware and change settings you would need such as board type, and steps per mm.

Edited 3 time(s). Last edit at 09/02/2013 12:06PM by jamesdanielv.

Forgive me for stating what may already be obvious but I also recently put together a Prusa i3 which had precompiled firmware with the HEATER_0_MAXTEMP value (in the firmware source) set to 235.

You'll need to get the Arduino.cc app, get the Marlin firmware source, make sure HEATER_0_MAXTEMP is set to something that makes sense for your hot end, then recompile and upload the firmware.

There is an option on the menu to change max temp but it is for auto-heating (where printing can be paused if the nozzle temperature drops, usually a problem only with inefficient power supplies and/or heating elements).

The magma hot end can go at least up to 275 so that's definitely a reasonable setting. Good to know that someone has managed to get good PLA prints from a magma hot end, so far I only have mine working with ABS!

on another note settings don't automatically stay in firmware unless you save them, they are lost as soon as sd card finishes a file, or the printer is reset.

I am having a similar issue, it says the hotend is 468 degrees, which I don't think is correct. I have the MKS Base board and used the following settings as stated on the wiki link ( #define BAUDRATE 250000 //This will work fine for the MKS Gen
#define MOTHERBOARD 33 //33 is for RAMPS which the MKS GEN is compatible with MOTHERBOARD 34
#define TEMP_SENSOR_0 3 //If you have the NTC 100K
#define TEMP_SENSOR_1 0
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 3 //If you have the NTC 100K )

I honestly have no idea what the settings should be.
Joshy

Hi

My nozzle temp just keeps increasing until MAXTEMP error occurs. I have tried the firmware changes.

Should I change the thermistor? I have set the sensor type to 1. Is this OK?

Thanks

I am having the same problem, and I am sure it is a setting in the firmware.

THE PROBLEM IS, how do you change the firmware, makerfarm will not send me any instructions on how to do it.

These all metal Jhead come with aluminum hot ends and they just dont melt the plastic as well, nothing but cloging.

@rumjar86 you probrably are not referencing the right thermistor tables. Do you know what kind of thermistors you have?

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Hi

My nozzle temp just keeps increasing until MAXTEMP error occurs. I have tried the firmware changes.

Should I change the thermistor? I have set the sensor type to 1. Is this OK?

Thanks

That is probably a bad connection on your MOFSET