search

MKFirmware / MK4duo

MK4duo Firmware Printers 3D for Arduino and Arduino due
http://www.marlinkimbra.it
GNU General Public License v3.0
206 stars 117 forks source link

thermocouple support #733

Closed maukcc closed 5 years ago

maukcc commented 5 years ago

If we use -1 or -2 as temp sensor we get a TEMP_HE0_PIN was not declared error when compiling. In our pins file we have

define ORIG_HEATER_HE0_PIN 4

Is there anything we are missing?

MagoKimbra commented 5 years ago

The thermocouples have specific pins on the board where there are SPI amplifiers. What card do you mount? The pins are mapped to MAX6675_SS_PIN or MAX31855_SS0_PIN.

maukcc commented 5 years ago

We have our own mainboard with a MEGA on it. we are using a AD597 connected to analog pin 4

MagoKimbra commented 5 years ago

Ok i fixed it in configuration_pins. Re download...

maukcc commented 5 years ago

Thanks, that worked. But the readings are awful. With the same setup and repetier or marlin I get a straight line for my temps. Here I get a 10 degree dip every second or so. While the analog input signal is rock steady.

MagoKimbra commented 5 years ago

The analogue reading is the same for the classic sensors that for the AD595 or AD596, what changes is the conversion formula. When it reads the ADC pin it reads the digital conversion of the input value from 0 to 1024 (in decimal) then converts it to temperature with the rule: raw float (AD595_MAX) / float (AD_RANGE)) ad595_gain + ad595_offset;

raw is the value read in decimal from 0 to 1024. AD595_MAX is 500 which 5v for 100 AD_RANGE is 1024 the gain and the offset set with the M595 command is usually 1 for gain and 0 for offset.

If you dance 10 ° it means that the ADC reads a value that varies by 10 °. If there were problems with the firmware you would have the same problem with the classic temperature sensors ...