Heater decoupled ?!?!?

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  • That was the table I was talking about.

    The right number is the temperature.

    The left number you can convert with this formula.
    (X/1023*5)/((5-(X/1023*5))/4700)

    Place the left number, like 981 in the two positions marked X. It will calculate the resistance, for example 981 gives the resistance of 109778.57 and the temperature of 23C. Then you type the resistance and the temperature into the web configuration tool.

    Excel or Openoffice will work best for calculating,,,
  • THANK you very much !!!
  • I continue thinking about difference between manually extruded and printed wire thickness.... In addition I have to find the way to extrude correctly from the first row with "E" in it.
  • Hi again,

    After many evenings fight with my printer and many changes, finally I received almost good results. And because I can't stay and do nothing, I made one general upgrade.

    My Bed was standard like THIS and even after upgrading power supply to 24V it has reached 120°C after more than 25-30 min. That's why I decided to go to 220V.

    I got 290*270*2.5 mm aluminium plate and purchased 800W (220V) heather for it. I use 40A SSR relay for driving the bed's heater. Now all is assembled and today I made first tests. The heater is powerful enough for heating the bed for under 2 min and 30 sec. But this in fact occurs as a big problem again. work  The system do not predict that with this rising speed, the temperature will continue to grow by inertia to very high values and has switched off the heater at 118°C. I lowered the desired t° to 100°C but this do not help.

    image

    image
    After many tries and setting the "Temperature manager" to "PID controler", I lowered by 1/2 all values that play in PID correction:
    Max PWM value[0-255]  - 128
    Decouple test period[s] > 90000
    PID drive minimum[0-255] - 80
    PID drive maximum[0-255]  - 128
    PID P  - 98
    PID I - 16
    PID D  - 145

    I changed also thous values in EEPROM............ without success.

    The Firmware decoupled the bed heater, because after reaching the target temperature (for example 100°C) and switching off the heater, the temperature rises by inertia to more than 127-130°C.

    So Can you tell me what can I do to LOWER the temperature's rising speed?  
  • That reall is a bit of overpowered. The only reasonable solution would be to never use the full power. So reduce max pwm/drive maximum to 32 ot 64 depending on what works. That should give the controller enough time to react.

    Alternatively set decouple test period to 0 to disable it, but with so much power I guess it would be better to not do that. I would also add a hardware temperature off switch for safety.
  • Thank's, I'll test it this evening!

    Just for confirmation: I use as a "Temperature manager"  -> "PID controler" , and In the firmware it correspond ti number "1"? Am I right?


    And another question, connected to the bed leveling:

    image
    The Left or the Right way to measure points for autoleveling is correct?

    Best Regards
  • Yes 1 is PID controller.

    Both measuring points work, but it is best to use the left one so you have least bending while measuring. If measruing takes no force it would not matter.
  • edited June 2015
    Thank you for the advice. 
    I set pwm/drive maximum to 64 and now my bed is PERFECT !

    I noticed two thing:
    1. If i make homing for X and (or) Y for second (or more) time after start / restart, the Z axis motors rotates between 1/4 and 3/4  rotations!?!? I'm not sure why this is happen but it's a fact.

    2. If I start to hate both: the Extruder and the Bed, and because now my bed reach faster desire temperature, 2-5 sec after that the Extreuder's heater stops and its temperature goes down. I cant manage it trough Repetier Host, and must to do Emergency Stop. After restarting the controller / host all works OK. 

    Any ideas?
  • 1. If you do G28 X0 or G28 Y0 the z motor should not move unless you have autoleveling enabled and rotation is tilted. Then xy moves need to move z as well.

    2. What does the log say? Does enabling/disabling dry run make it work again?
  • edited June 2015
    I just write the follow:

    G28 X0  -  and send it to printer

    The same is with G28 Y0. iF i DO THIS after preview made homing, the printer rotates the Z motors.
     
    ====================================

    Today again the same temperature "problem".... I didn't test enabling/disabling dry run


    image

    The most interesting is that on the LCD the temperature is set as "0" - not 275 as have to be.
  • If lcd shows 0 it is disabled and host did not notice as it still shows the 275.

    You should disable command preview in log so you can see error messages for longer then 0.1 seconds:-) But with a 0 in display and 0.92.3 firmware (is it) it would be a dry run enabled and host shows it did not enable debug.
  • edited June 2015
    Yesterday I checked very precisely what really happens... So The printer really become in "Dry Mode"  without any notifications on the LCD and in the Host nor in the Log, nor indicating "Dry Mode".  Just the temperature of the extruder falls down although the target temperature stays 275 °C on both: LCD and Host. May be this will happen with the bed temperature тоо, but it is highly inertial system.

    Switching "Dry Mode" ON / OFF really helped me to take back control over the heaters.

    This is not so big problem (when I know for it) but is annoying ... 

  • @Repetier / @DBSDBS:  I must also say that your English is fairly good!  We Americans should learn from your efforts and we should try harder!  Thank you for your very public support of this effort!
  • Thanks @LouGeezer ... You are so polite...

    I would like to ask again for the problem with switching off the extruder's heater!!!! Just on LCD (and in the temperature tab)  I can see that the extruder's heater goes OFF ~ 5 sec. after reaching the desire temperature from THE BED! Nothing else indicates for the "problem". It is very hard to take back a control over it. I do not see any indication for going in "Dry Mode" too. The last few times, switching "Dry Mode" ON / OFF did not helped me! I have to disconnect and reconnect the host, and / or to press "Emergency Stop". Some times this do not helps too. 

    Can someone offer me a decision? 
  • It is a problem that only happens on some printers, but not on ours, so we can not test or reproduce it. We thought it might be a graphic display (what lcd do you have?). On the weekend I assembled one on my printer but got no temperature fail. So it either something else or a combination of factors only creates the problem. So any hint is welcome to find what cause sthe problem, especially
    - which firmware (version and date) did you use
    - Hardware / printer type
    - Copy of configuration.h
    - Arduino IDE version
    - OS you compiled firmware

    Hopefully with enough data it shows a pattern when it happens and when not.

  • edited July 2015
    So, the answers:

    1, Firmware: Repetier 0.92.3

    2. Cartesian printer (similar to THIS) - self made. 
    Arduino Mega 2560 + RAMPS 1.4 + 5 * A4988. 
    220V 800W heat bed connected trough 40A SSD relay. 
    Extruder's heater: Cartrige Heater @12V
    2004 LCD Display controller adapter for 3D printer

    4. Arduino IDE - version 1.6.5
    5. OS: Windows 7 Ultimate
    6. The last LOG from yesterday!
    7. Brand new Repetier Host 1.5 !  Nothing different (as heaters behavior) from the preview version!

    Yesterday I spend more than 4 min to take back a control over the heater. Оn the host I can just see that the heaters temperature falls (and the heater do not work in the temperature sheet) without any other indications !!! On the LCD display I can see that the desire heaters temperature is "0" !

    I switched the "Dry Mode" ON (+ OK) and than OFF (again + OK) - nothing
    Pressed "Emergency stop" many times - nothing
    Disconnect and reconnect - nothing.
    Again from the beginning..... and (I'm not sure after what) the connection with the was restored.
    Meanwhile the temperature was fallen to ~ 140°C from almost 260°C...
  • May I point out that this started when you connected an 800W heater?

    What is your max heat bed set to?

    As Repetier said. Disable command preview in the log as all the log shows that you posted in the image is temperature requests which does not help us.

    What is your hotbed's PWM and PID PWM set to?
  • Yes you are right, the problem begins after changing the "Bed Heat Manager"

    Here are my EEPROM settings and my Configuration.h

    This is the part from the EEPROM concerning the bed:

    <epr pos="106" type="0" value="1">Bed Heat Manager</epr>
    <epr pos="107" type="0" value="32">Bed PID drive max</epr>
    <epr pos="124" type="0" value="5">Bed PID drive min</epr>
    <epr pos="108" type="3" value="196.000">Bed PID P-gain</epr>
    <epr pos="112" type="3" value="33.000">Bed PID I-gain</epr>
    <epr pos="116" type="3" value="290.000">Bed PID D-gain</epr>
    <epr pos="120" type="0" value="64">Bed PID max value</epr>

    I'm not at the printer, so I work only with exported data from EEPROM. As I can remember, there was 2 settings for PWM... Both are set to 64 in the EEPROM.

  • Does your printer not loose 12V power when the heatbed turns off?
  • edited July 2015
    The heat bed is connected trough SSR relay (40A)... In fact there is NO connection between the bed and the RAMPS. The consumption of the "management" side (connected to the RAMPS) is <10 mA. 

    In addition: The problem with extruders heater occurs ONLY on initial heating process... and around 5-7 sec. after switching off the bed's heater. After restoring the control over the extruder, the problem disappears although the bed's heater switches ON / OFF to maintain the temperature. 

    And at the last, the 12V power supply unit maintains 60A consumption without any problems !!! Before that 220V bed, I had a conventional reprap bed @ 12V with 15A consumption and this problem never had exists. However, I must admit that than this situation was impossible, because the bed NEVER had reached 120°C....
  • The problem was in the Firmware.

    I made new one and flashed with it the Arduino mega. Now I think all the problems with the extruder temperature management are solved.

    Thank to all for the ideas and support!

    Cheers!
  • I use a davinci 1.0 and the problem was a cheap connector that comes on davinci 1.0 model that carrys the current to the head so I cut it out and soldered the wires directly together and that fixed it for me
  • The problem was in the Firmware.

    I made new one and flashed with it the Arduino mega. Now I think all the problems with the extruder temperature management are solved.

    Thank to all for the ideas and support!

    Cheers!
    I have the same issue. What was it in firmware that fixed it for you?

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