Temperature Issues

Hey,

I just put together a CartesioW dual extruder and configured it as per (http://mauk.cc/mediawiki/index.php/Edit_firmware). When I turn on the printer I get a MAXTEMP error. The thing is, all the temperatures read 0 degrees C.

Things I've tried:
-Checked all connections to make sure they were correct.
-Checked that all the thermocouples and thermistors were producing the correct resistance when unplugged from the printer.
-Tried disconnecting extruders: Result: Didn't make a difference. All temperatures remain 0 degrees.

-Tried changing Configuration.h to:

#define HEATER_0_MINTEMP -10
#define HEATER_1_MINTEMP -10
//#define HEATER_2_MINTEMP 0
#define BED_MINTEMP -10

#define HEATER_0_MAXTEMP 3500
#define HEATER_1_MAXTEMP 3500
//#define HEATER_2_MAXTEMP 275
#define BED_MAXTEMP 1500

I now get a MINTEMP error and all readings are 0 degrees still. However, if I unplug one of the extruders the bed temperature reads 22 degrees C (approximately correct and proceeds to go up and down when I apply/take away heat to it) the unplugged extruder reads 850 C and the plugged in extruder reads 0 C. It doesn't matter which extruder I unplug and when both are unplugged they both read 850 C.

I have no idea what could be wrong at this point. Any suggestions would be greatly appreciated.
Thanks in advance.

Few questions to try to help:
What board are you using?
Thermocouples for the extruders and thermistor for the bed, right?

If answer to 1 is ramps and to 2 is yes, are you using any additional electronics to connect the thermocouples to the board?

For what I can read you are missing your signal amplifiers for your thermocouples.

The thermistor in your bed reads right because is a "plug and play" item for ramps, but thermocouples are not.

Edited 1 time(s). Last edit at 10/21/2014 09:56PM by ggherbaz.

Thermocouples don't work the same way thermistors do, rather than changing their resistance with temperature, they generate a voltage, which the arduino adcis not sensitive enough to read directly. You need an interface chip to read them and pass that data to the arduino.

If you do have an interface, then it may be returning an error code rather than a temperature. Possible faults include an open thermocouple, or a thermocouple shorted to GND or VCC.

Thanks for your help guys. To answer your questions:

I'm using a CN Controls V1.0 board made by MaukCC: [mauk.cc]
with an Arduino Mega plugged into it.
There is an Extruder Controller: [mauk.cc]
between the thermocouple and the board with what looks like an AD597A Chip on it (I assumed this was for amplifying the thermocouple signal but I may be wrong).


Yes it is a thermistor for the bed and thermocouples for the extruders.

Any suggestions on how to diagnose where the problem is? All I could find for an electronics diagram for the CartesioW was this: [mauk.cc]
which isn't so helpful in figuring out what pins lead to where.

Thanks again.

Not familiar with that board sorry, the AD597A should be for the thermocouple and looks like you have some drilled holes in the board to solder your cables, but not sure of that and how to set it on firmware. Best advice is to contact them and get all the info you need.

Hi,

Has this been cleared yet.

Besides the 24V going into the toolcontroller, there is also a seperate 5V and GND going to the AD597 to get a stable signal.
Is the 5V present?

You can also contact me directly at josatmaukdotcc