Geeetech

I must be misunderstanding. No speed other than S255. runs my fan...which then is full speed only. On the LCD control knob, under control>temp>fan, only when the value is turned all the way up to 255 will the fan come on at all...again either it is off or on 100%.

Am i missing something? That to me is not pwm control of part cooling fan. If any M106 S(value) shows up in my gcode files generated by slicer, value must be 255 or fan will not run at all.

_kaktus_ wrote: Tue Sep 04, 2018 11:37 pm Hi

zonalimitatore wrote: Tue Sep 04, 2018 4:22 am Yep.Or on or off....i dont know why implement pwm and mount a non controlled fan

I also don't understand why you are saying that.
To my knowledge, it is possible to control the fan speed smoothly, which has only two wires connected, e.g. +12V and GND.

This was the solution used by the manufacturer.

If you are interested in details how it works, it is worth reading a little.

zonalimitatore wrote: Mon Sep 03, 2018 10:20 pm

Code: Select all

M106 P0 S255*16

or just

Code: Select all

M106 S255

I wonder where you got the part of the parameter *16

Parameters
Pnnn Fan number
Snnn Fan speed (0 to 255)

Sours.

I have a control without it
In my opinion it is wrong and the whole command in this form is ignored by the interpreter.
Would you like to explain to me?

For *16 my mistake.
About pwm.I know. What i say is: it's strange have the possibility to set by pwm value,with a board that have the pin,and mount a 2 wires normal fan

Hey hey gentlemen.

AFewSkroosLoose

If it happens as you say it is not a reason to be lucky.
This may be due to the heavy starting of the motor.
In order for the engine to rotate, it needs certain conditions. A small filled PWM signal does not meet these requirements.
This is an individual matter for each model of electric motor.

You can do some experience.
Start the engine at full power and then try to slow it down.
I know that this will not solve your problem, but if you want to, you will have an interesting experience.

zonalimitatore

OK. Mistakes happen, I understand. I think you should test your idea before giving advice to another user.
Didn't you sometimes see this *16 in your log?

I'll tell you a little about the fans. Let it be, - once again I will write it in this forum.
Your controller is GT2560 Rev A+ right?

In that case: All sockets have 3 outputs.
In this case, you can connect a fan with two wires: Vcc and GND
and three wires: Vcc, GND and Fan Tach.
Correspondingly, the colours are: red and black and yellow.
Note that only two signals are connected in the diagram. Fan Tach signal is omitted. If the fan is equipped with it, it generates two impulses per full revolution, to be counted by the controller.
This still has nothing to do with the PWM.

Now look at the socket at the bottom of the drawing.
There is a small addition in the form of the N-Channel Power MOSFET transistor.
It does nothing else than cyclically power the connected fan.
This is done in tact of the given PWM signal, on the GND line.

Forgive my little technical language but I tried to write it straightforwardly so that it would be understood by a larger number of users.
Fans with four connections are also produced. In this case, apart from the ones discussed above, they have a special lead for "Fan Control" signal.

uuuffff
A lot of talking. One big OFFTOP.

I greet you very warmly.

Kaktus thanks for trying to help. I am not an electronics expert. So the fan that came with my machine is plugged into a pwm output, but since it has only two wires this is why it is only on or off and not controllable speed?

I have gt2560 revB board, not revA.

My question i need answered plainly is this: what must I do to get speed controllable fan working for my parts cooling? Such that if i tune dial on LCD to 1/4 or 1/2 I get corresponding % of blowing speed...such that if I use M106 S127 I will get 1/2 speed? I would like controllable fan to experiment with optimum printing conditions.

Do i need diff style fan?

Thanks for your help.

Hello

AFewSkroosLoose wrote: Wed Sep 05, 2018 5:12 am ...
So the fan that came with my machine is plugged into a pwm output, but since it has only two wires this is why it is only on or off and not controllable speed?
...

No
No

PWM = Very, Very fast switching on and off. The speed of the fan can be influenced by adjusting the duration of the switch-on time.

AFewSkroosLoose wrote: Wed Sep 05, 2018 5:12 am ...
I have gt2560 revB board, not revA.

My question i need answered plainly is this: what must I do to get speed controllable fan working for my parts cooling? Such that if i tune dial on LCD to 1/4 or 1/2 I get corresponding % of blowing speed...such that if I use M106 S127 I will get 1/2 speed? I would like controllable fan to experiment with optimum printing conditions.
...

Generally speaking, this is how it is supposed to work. But you said earlier that there are problems with this at your place. Read carefully what I wrote before. If something is not understandable, ask.

AFewSkroosLoose wrote: Wed Sep 05, 2018 5:12 am ...
Do i need diff style fan?
...

I don't know what it is.

I asked about three wires because you gave more information than apparently was necessary and discussed 3 and 4 wire fans.

I am having difficulty finding schematic with labeled connections for gt2560 revB...it looks much different than revA from I see. Cooling fan is bundled with many more cables into one big connector, instead of individual fan connector. The fan is labeled on its back 24v...from youtube video and description of revB board on geetech site, the pwm output is only 12v. This is why I believe fan is weak and will not run on anything but S255.

Perhaps putting correct 12v fan on machine will lead to full pwm control.

Does this sound reasonable solution?

Thanks

Hi


In my opinion, you have discovered the reason for the complication.
Applause for independent work.

I have a surprise for you.

_kaktus_ wrote: Fri Sep 07, 2018 9:33 pm I have a surprise for you.


Fan_con_GT2560_RevB.png

Could anyone point me to the type of connector the fan uses? I want to buy one on Farnell or Digikey... does anyone know what type it is / what the pin spacing is etc?
For example: https://www.digikey.co.uk/product-detai ... -ND/926565

Thanks!

Hi.


The controller board uses very many types of connectors, as for me there is too much variety.

I tried to identify them all and described them from my presentation.