Nozzle gets heated 20°C above set temperature

[TVG3000 1]

Hi everyone,

When I set my nozzle temperature to for example 240, my UM2 keeps heating it past 240.

I see its heats to 260 and then the temperature slowly drops. If I go from 40 to 80, it heats till 110 before dropping.

This isnt normal behaviour right? I thought it slowly approached the desired temperature without going over it by this amount.

Both heater and sensor seem to be installed correctly.

[gr5 2,295]

Maybe you have a 35W heater instead of 25W?  You can test the heater wattage if you have an ohm meter - just disconnect it at the PCB and measure the resistance.  Wattage = 24 * 24 / resistance

UM2+ has 35W heater and has newer firmware with better PID values.

Anyway you can simply reduce the PID values bye the ratio of power increase.  So if you have a 35W heater then reduce all 3 values (P,I,D) by multiplying them all by 25/35.  Or you can run the autotune feature.

Cut and paste PID tuning info follows:

================================

========

35W nozzle versus 25W nozzle and gcodes

Adjusting the 3 PID values is pretty easy - in general you want lower values for higher wattage heater so if your heater is 30% stronger you want to decrease the values by 30%.

The easiest way to play with the PID values for the nozzle are to install pronterface (it's free - you don't even really install it, just download it and run it) which is here:

http://koti.kapsi.fi/~kliment/printrun/

Then connect a USB from your computer with pronterface to the printer and start it up and connect.  It will immediately show the current PID values over on the right side and you can change them.  The gcode commands (you can just type in gcode commands in pronterface) are discussed here:

http://reprap.org/wiki/PID_Tuning

Or just choose among these gcodes:

M301 - set PID

M303 - autocalibrate PID

M500 - save PID values (CRITICAL OR YOU LOSE VALUES WHEN YOU POWER CYCLE)

M503 - display PID (and other) values (done automatically on connect by pronterface anyway)

above gcodes explained in detail here:

http://reprap.org/wiki/G-code

Edited February 26, 2016 by Guest