PID Autotune

[mrjohnk 0]

Since I'm getting ready to update my firmware to the latest Marlin version, I wanted to go ahead and do another PID autotune on the hotend so that I can get a better performance. I'm running a 24V power supply and printing ABS. Using default PID settings work, but the hotend overshoots the 255 degree temperature upon initial heat-up to about 265, but holds good at 255 after that. The goal is to reduce the initial overshoot. Using the pronterface GUI, below is the output I received. Any idea what caused it to fail the autotune?

Thanks.

John

SENDING:M303 250

PID Autotune start

ok T:46.42 @:127

ok T:46.42 @:127

ok T:46.91 @:127

ok T:48.34 @:127

ok T:50.05 @:127

ok T:52.61 @:127

ok T:55.66 @:127

ok T:59.57 @:127

ok T:63.66 @:127

ok T:68.27 @:127

ok T:73.21 @:127

ok T:78.58 @:127

ok T:83.89 @:127

ok T:89.32 @:127

ok T:95.21 @:127

ok T:100.92 @:127

ok T:106.60 @:127

ok T:112.30 @:127

ok T:118.32 @:127

ok T:124.11 @:127

ok T:129.82 @:127

ok T:135.44 @:127

ok T:141.42 @:127

ok T:146.94 @:127

ok T:152.31 @:0

ok T:157.96 @:0

ok T:162.78 @:0

ok T:166.99 @:0

PID Autotune failed! Temperature to high

 

[mrjohnk 0]

I figured out that I used the wrong syntax by eliminating the "S" in the passed parameter. Corrected syntax is working properly:

M303 S250

John