Why won't extruder2 energize the 2nd hotend

I have repetier 1.6.2 driving my smoothieware on a MKSbase ver1.3 board with dual extrusion on my RepRap printer.
Extruder1 has always worked nicely as a single extruder in Repetier but now that I am advancing to dual extrusion I am having difficulties with the 2nd extruder setup.

What works:
I believe that the firmware & hardware is setup correctly because  when using LCD interface I can turn on the temperature to extruder1 or extruder2 and have accurate results reported back in the LCD display and confirmed using my thermometer.
When using Repetier in manual mode I can energize the extruder2 motor & extruder1 motor accurately.
Temperature controls for extruder1 work nicely in manual mode.

What doesn't work:
Turning on extruder2 temperature yields no input to the printer for extruder2 in manual mode.
In manual mode the thermistor reading for extruder2 seems to show thermistor1 information  ie.  after turning off temperature on extruder1 and turning on temperature for exturder2 the extruder2 temperature reading drops in correspondence to the cooling of extruder1 as verified by my thermometer.

Any thoughts would be greatly appreciated.

Thank you,


  • Please enable logging so it logs all communication to a file in repetier workdirectory. Then heat extruder 2 and later check the log for output. I'm interested in the response for the temperatures requested with M105. Would not be the first case that a firmware changes format making it impossible to read correct values. But that still does not say why it does not heat extruder 2. Maybe smoothoeware does understand the format. If I remember right host will set temperature like this;

    M104 T1 S200

    and it will always show active extruder. So what happens if you change active extruder first. Does it still show extruder 1? Does it now always heat extruder 2 and not heat extruder 1 any more?

  • Thank you for the prompt response.  I turned on logging and went through the paces of setting up a print.  Energize E0, then switch to extruder2 and energize E1.  Selecting 2nd extruder and energizing E1 does nothing, selecting 1st extruder and energizing E0 works nicely.  I did note that when extruder2 is selected the temperature readout is coming from the thermistor on E0.  When I select the Extruder1 all behavior is as it should be for E0.

    Where would you like me to place the log file ?  seems a bit much to paste here.

    Very much appreciated.
  • It is worth noting that I am now printing with PVA soluble structure on Extruder2 and ABS on Extruder1, using repetier host and slic3r.  I have set the temp for Extruder2 using the LCD interface to the MKS sBase.

    The only issue seems to be that I do not have thermal control of extruder2 in manual mode with Repetier.
  • edited March 2017
    so for understanding, extruder 2 works from lcd so just a "stupid" question

    did you setup repetier host for 2 extruders?

    see config->printer settings->extruder-> number of extruders
  • You do not need to past the log. I'm only interest in the output of M105 when heating. So just pase a few examples of this. I's something like

    T:50 /200 @:255 B:30 .......

    What does the docs say how to set temperature for extruder 2 with smoothieware. Also if you check commands in log window you should see what host sends to activate printer, so you can compare the commands.

  • From Repetier log:

    < 17:38:12.163 : N21 M104 T0 S200*16
    > 17:38:12.163 : ok
    < 17:38:12.335 : N22 M105*23
    > 17:38:12.335 : ok T:23.4 /200.0 0
    < 17:38:15.392 : N23 M105*22
    > 17:38:15.392 : ok T:23.9 /200.0 0

    < 17:43:56.518 : N138 M104 T1 S200*40
    > 17:43:56.518 : ok
    < 17:43:57.844 : N139 M105*44
    > 17:43:57.844 : ok T:199.8 /200.0 0
    < 17:44:00.902 : N140 M105*34
    > 17:44:00.902 : ok T:199.9 /200.0 0

  • I will take note of what command is displayed in the LCD when I set the extruder2 temperature through the LCD and report back.

    I will review the smoothieware documentation regarding dual hotend setup to see if there is something that I have missed.

    Your feedback is very much appreciated.
    Thank you
  • One thing I see is

    ok T:199.8 /200.0 0

    which should be

    ok T:199.8 /200.0 @67 ;T0:199.8 /200.0 0

    Normally firmwares report all extruders with temperatures and not only the non active ones. After all it is not apperent from the answer which is the active one and if you change it through sd card or lcd how should host know you did change it. So this explains why we do not see all temperatures in host, but it is still open why "M104 T1 S200" does not heat the second extruder.
  • I can confirm that this data did not include changing temperature by LCD interface.  The above log data represents manual mode through Repetier.  The above information was cut from the very 1st part of the log.

    Regarding the statement :
    "ok T:199.8 /200.0 @67 T1:32.1 /0.0 @0
    which should be
    ok T:199.8 /200.0 @67 ;T0:199.8 /200.0 @067 T1:32.1 /0.0 @0"

    Is there an action that I can take to correct this ?

    Thank you,
  • Reading this doc

    is not very informative. It does not mention the T parameter for M104/M109 so you would need to activate Extruder 2 and then set temperature since it seems it will ignore that parameter so it only sets temperature for that. 
    It also does not say why it does not output T0 and T1 or even mentions that it does output something different then current selected extruder. Having no printer with smoothieware I lack a bit of experience how they sometimes behave, but I guess they just do different here only implementing the basic functionality. So please try switching extruder and then set temperature and report how that changes things.
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