temp sensor on extruder follows bed temp when extruder heater off
I'm building a rep rap and can't seem to get temp settings right for the life of me.
I now have two honeywell thermistors (one for bed, one for extruder)
at room temp the bed reads 20C and the Extruder reads 30C-this doesn't make sense since they are the same sensor type and were selected properly in the configurator.
i commanded extruder to 40C and bed to 30C and i read ~80C on the extruder and 30C on the bed as measured by a fluke thermocouple readout.
I then decided to turn off the bed and waited till it went back to room temp. bed cooled to room temp as indicated by both thermocouple and repetier host software. Extruder remained reporting ~40C and measured ~80C via thermocouple
I then decided to turn the bed back on to a temp higher than the extruder and commanded 50C to the bed. As bed temp increased the extruder temp also started to increase as reported by the repetier host software but remained ~80C as measured by thermocouple. The graph on repetier shows extruder temp at ~55C with bed temp at 50C and the graphs are parallel.
any ideas? Please help
I now have two honeywell thermistors (one for bed, one for extruder)
at room temp the bed reads 20C and the Extruder reads 30C-this doesn't make sense since they are the same sensor type and were selected properly in the configurator.
i commanded extruder to 40C and bed to 30C and i read ~80C on the extruder and 30C on the bed as measured by a fluke thermocouple readout.
I then decided to turn off the bed and waited till it went back to room temp. bed cooled to room temp as indicated by both thermocouple and repetier host software. Extruder remained reporting ~40C and measured ~80C via thermocouple
I then decided to turn the bed back on to a temp higher than the extruder and commanded 50C to the bed. As bed temp increased the extruder temp also started to increase as reported by the repetier host software but remained ~80C as measured by thermocouple. The graph on repetier shows extruder temp at ~55C with bed temp at 50C and the graphs are parallel.
any ideas? Please help
Comments
I then turned off extruder heater and watched the temp come down to ambient via the TC. However on Repetier it only came down to ~53C (bed is at 50C)
I purchased my thermistors from a local 3D printing company and they told me it was option 7 in Marlin. I looked up option 7 in Marlin and it is the same honeywell themistor which I selected in Repetier.
Can you speak to the tracking issue? Why would the readout on one thermistor follow the other when it's not actually reading that temperature? Is my ADC possibly fried? Some kind of weird crosstalk? This is mind boggling to me and appears that it would be firmware related. I have checked the ADC with a potentiometer previously. Is there a way to report the ADC value in Repetier? I had previously tried Marlin and had found a line that I uncommented which wrote the ADC value to the Serial monitor when running the M105 command, but I haven't been able to locate a similar line in Repetier.
I agree that surely something is wrong I just have no idea what it could be at this point. Please help me with troubleshooting suggestions...I'm at a loss at this point. I have spent weeks at this point dealing with temperature issues.
Please help
At this point if I knew someone willing to provide support, I'd probably be willing to pay. I hope what you say is not true and that someone can help me.