Temperature are are shown all negative bed and extruder

beginner

Hi together,
so thats my first issue in 3D printing and now i have already a issue with bed and extruder temperature.

I use Firmeware 0.92.9 with ramps 1.4 and my own printer design.

when i connect the temperature sensors both shown room temperature but with negative sign -21 °C.

I have three temp sensors and the behavior is always the same.

In cofiguration file i use Sensor Type 1 (100K NTC).

i would be glad if somebody could help me a little for the right way.

BR
Sven

Repetier

Wrong analog input might be a reason. If not connected they show hottest or coolest temperature in table. Same goes if the checked analog pin is not the one where the sensor is connected to. Not that the ramps has so many inputs. Also make sure that you have a thermistor and not a thermocouple and that is really of that type.

lmcbmai

I recently finished building new printer and was also getting negative temperatures when thermistor was not connected.
Check your wiring, if you have a tester, measure resistance of the thermistor (typically should be close to 100 kOhm), make sure you have correct pin assigned.
To narrow down the problem you can temporarily replace thermistor with 100K resistor directly attached to sensor connector on your board and check if the reading changes. 

beginner

Thank you for answering.

The thermistor seems to be o.k. I measure 110kOhm (100kOhm=25°C). When I heated up the thermistor with my hand the measured temperature will also goes higher up to 35°C . 

It is possible the repetier software show the temperature values always with "minus" in front ? when I look at the temperature curves the value seems to be positiv and  the graphical LCD Display show  also positive values.

I ´m a little  confused now.

lmcbmai

when I look at the temperature curves the value seems to be positiv and  the graphical LCD Display show  also positive values.

So, where do you see negative values?

RAyWB

if you mean repetier host , it´s not a minus sign but simply a hyphen followed by a space.

beginner

Thanks all . I were wrong I tought it were a minus sign in repetier Host and I investigate a Couple of hours for Troubleshooting . So learning by doing.