This article provides general information for adding a chamber thermistor to the Vivedino Troodon as well as changing steps/mm with Rep Rap firmware. 

Hardware Installation for Chamber Thermistor to control the Case Fan on the Vivedino Troodon


Modifying Rep Rap Firmware to add a Chamber Thermistor to control the Case Fan in Rep Rap firmware:

Stock Configuration

; --- Case Fan ---
M950 P5 C"duex.fan7"
M42 P5 S0.0 ;

; --- Controller Fan ---
M950 F3 C"duex.fan8"
M106 P3 S0.5 H1 T50 ;

Updated Configuration (you will paste below code over the stock configuration)

; --- Case Fan --- no thermistor
;M950 P5 C"duex.fan7"
;M42 P5 S0.0 ;

; --- Case Fan --- thermistor
M308 S6 P"e1_temp" Y"thermistor" A"CHAMBER" T100000 B4138 C0 R4700   ; define chamber temperature sensor
M950 F5 C"duex.fan7"
M106 P5 C"Chamber" H6 S6 B0.3 T50

; --- Controller Fan ---
;M950 P4 C"duex.fan8"
;M42 P4 S0.5 ;
M912 P0 S-7.5; Temp offset
M308 S3 Y"mcu-temp"  ; configure sensor 3 as temperature warning and overheat flags on the TMC2660 on Duet
M308 S4 Y"drivers"
M308 S5 Y"drivers-duex"
M950 F4 C"duex.fan8"
M106 P4 C"Case" H3:4:5 L0.4 X1 B0.3 T25:40 ; set fan run off sensor 3 value

Adjusting Steps/mm:

Stock Configuration

M350 X16 Y16 Z16 E16 I1     ; microstepping with interpolation (I1)
M92  X80 Y80 Z400 E685     ; steps per mm - with bt
M566 X900 Y900 Z602.65 E600 P1     ; maximum instantaneous speed changes (mm/min) (jerk)
M203 X20000 Y20000 Z1500 E3200     ; maximum speeds (mm/min)
M201 X3000 Y3000 Z500 E3200     ; accelerations
M204 P1500 T2000
M906 X1200 Y1200 Z1200 E400 I40     ; motor currents (mA) and motor idle factor in per cent
M917 X70 Y70 Z80 E70
M84 S60     ; set idle timeout

For example, changing extruders from a stock Orbiter(Esteps - 685) to LGX lite(Esteps - 562) The M92 line will need to be changed.

Updated Configuration (for LGX Lite, copy over the M92 line with below)

M92  X80 Y80 Z400 E562                            ; steps per mm - with bt

Slicer Settings for Chamber Thermistor/ Case Fan control (examples; use one line only, added to end of start GCODE)

M106 P5 T35; Set chamber temp for PLA

M106 P5 T45 ; Set chamber temp for PETG

M106 P5 T55 ; Set chamber temp for ABS