Marlin with Azteeg X3 and thermocouple sensor

Hi All,
This is my first build.
I got the Azteeg X3 board and the extruder with thermocouple sensor
Extruder

The Azteeg uses the AD849X chip for the themocouple input (which is 5mV/C)

but Marlin just support thermocouple use AD595 which has 10mV/C

What should i do to make it work ?

By the way, this what i'm making (attached)


Thanks all,

Cuong

change the sensor value to -2 in config file....

I have a Azteeg X3 with shield. A K type Thermocouple is hooked up to pin11 for the Heat bed. I am using Marlin.
Setting the Temp Bed sensor to -2(MAX6675) reads nothing
Setting the Temp Bed sensor to -1(AD595) reads 470 (should be 23)

How do I change the readings to be correct for a AD8496 and a K type thermocouple.
I found the below code in the firmware. Can I just change the Formula? If so How?

// Overflow: Set to last value in the table
    if (i == BEDTEMPTABLE_LEN) celsius = PGM_RD_W(BEDTEMPTABLE[i-1][1]);

    return celsius;
  #elif defined BED_USES_AD595
    return ((raw * ((5.0 * 100.0) / 1024.0) / OVERSAMPLENR) * TEMP_SENSOR_AD595_GAIN) + TEMP_SENSOR_AD595_OFFSET;
  #else
    return 0;
  #endif
}

Donny

Edited 1 time(s). Last edit at 01/01/2014 05:24PM by DonnyM.

SO no one has a K type thermocouple working with a Azteeg X3 and Marlin. Bummer

Yesterday I got the combination Azteeg X3, Repetier 0.83 fw, Repetier Host 0.95c and K-type
thermocouples to work.

change
EXT0_TEMPSENSOR_TYPE from 1 to 60 and
HEATED_BED_SENSOR_TYPE from 1 to 60 in configuration.h

change
#define TEMP_0_PIN from 13 to 4 and
#define TEMP_1_PIN from 14 to 11 in pins.h
(for the appropriate motherboard type, 34 in my case)

In the Repetier firmware file "Extruder.cpp" you will find the code for AD8495
(in two places if I remember correctly).

Don't know how snippets of code from one firmware will work in another but the hardware
in the Azteeg is working as it should.

The tickbox "Check Extruder & Bed Temperature" in "Printer Settings" in Repetier Host
was a pitfall at first but that may not apply to your setup. Hardware and firmware were OK
but I had told it not to display any temperatures at all... My bad!!

Here's how I did it if you would care to know. I have the version 1.1 shield and on it are terminal blocks (I'm not sure what shield you said you have). Anyway, the terminal I hooked my thermocouple up to is TC1 and on the X3 main board it connects to analog pin 11 which is pin 2 of the EXP2 header.

In Marlin I set #define TEMP_SENSOR_0 to -1 (for thermocouple with AD595) in the configuration.h tab. I'm using my thermocouple on my primary hotend (SENSOR_0) but I suppose you just need to change the one that you are using a TC on.

Then, in Configuration_Adv.h find this code:

Quote

//These defines help to calibrate the AD595 sensor in case you get wrong temperature measurements.
//The measured temperature is defined as "actualTemp = (measuredTemp * TEMP_SENSOR_AD595_GAIN) + TEMP_SENSOR_AD595_OFFSET"
#define TEMP_SENSOR_AD595_OFFSET 0.0
#define TEMP_SENSOR_AD595_GAIN   2.0 //was 1.0 but changed to 2.0 for the AD8496 chip 4/12/2014

And change the AS595_GAIN from 1.0 to 2.0

The code you posted was a clue along with the fact that the AD595 apparently expects twice the voltage per degree C that our AD8496 does.

Lastly, I went to pins.h in Marlin and changed the definition for TEMP_0_PIN from 13 to 11 although I bet since 13 is also analog, I could have just plugged my TC into it and not have had to change the pin definition.

Quote

#define TEMP_0_PIN         11   // ANALOG NUMBERING-was 13 for a thermistor 4/12/2014

Quote
cncjoe
Lastly, I went to pins.h in Marlin and changed the definition for TEMP_0_PIN from 13 to 11 although I bet since 13 is also analog, I could have just plugged my TC into it and not have had to change the pin definition.

I think I'm wrong on using pin 13 for the thermocouple. I'm not sure but I think the AD8496 chip might physically be on the shield therefore TC1 (pin 11) and TC2 (pin ?) are the only pins hardwired to the chip.

I'm having some trouble with my AZTEEG X3 Pro and TCs using repetier. I'm using a later version than yours, but it seems still similar.. Can you tell me where I can find something to keep the thermo couple down from 999.99 deg C? I followed your instructions and got the thermocouple to show SOMETHING, unfortunately it's not a useful something...

Thanks

Edited 1 time(s). Last edit at 10/17/2015 09:07PM by laernmoer.