I have build a HyperCube 3D Printer (RAMPS-Based) with E3D V6 HotEnd and a PT100 Sensor and Amplifier, but the shown temperature is to high! Pronterface shows 80°C instead of around 20°C room temperature (unheated, Arduino Mega 2560 is only conected by USB). Marlin 1.1.8 is configured as shown in E3D documentation ('#define TEMP_0_PIN 3' in pins_RAMPS.h and '#define TEMP_SENSOR_0 20' in Configuration.h). So what's wrong? Thanks
Double check you don't have a really bad connection to the PT100. An extra 20 ohms in your leads and connectors would cause it to read high by 60C. Turn off all the power to the printer then do a resistance check. Disconnect the PT100 leads from the PT100 board and measure the PT100 resistance with a meter. If it's around 108 ohms, the PT100 is not the problem and it's either the the PT100 board or a software issue. If it reads around 131 ohms, there's something wrong in the PT100 or your wiring.
Hi Ephemeris, my multimeter shows a risistance of 126.8 kOhm directly at the thermistor connector, without extra wiring. And the voltage of the PT100 Amplifier Board (Signal to Ground) shows 1.42V (with or without the connected thermistor) instead of 1.2V (like John from E3D [Mail] said). That's strange! Do I really have such luck that probably the thermistor and the amplifier board are broken?
If that's a PT100 it's totally broken. On the other hand, that resistance is what a thermistor might read. Read THIS It says a 104GT thermistor reads 126.8k ohms at 20C. SOmehow you've got a thermistor instead of PT100 sensor.
In the meantime, I have checked that I made the following mistake with my order: I have ordered the 'Block & Sock V6 Upgrade Kit' and the 'PT100 Amplifier Board' instead of the 'V6 PT100 Total Upgrade Kit'. I thought it would be the better choice, because of the included Silicone Socks. But I did not checked that the 'Block & Sock V6 Upgrade Kit' did not contains the PT100 sensor! Now I have a Thermistor and a PT100 Amplifier Board ...OMG!?! How stupid!
