12v fans again.



  • Sorry, I have read some other posts about this but I still don't feel confident enough yet. I would like to run all of my fan's at 12v with everything else at 24v. I have a buck converter but I would rather use one of these little 12v 5a power supplies. So DC42 said, "…if all your fans are 12V, then you can remove the V_FAN voltage selection jumper, connect the +12V output of the buck converter to the centre pin of the V_FAN voltage selection block, and connect the fans as normal." So I just remove this jumper and connect the + to the center pin. Nothing with the ground? One wire out of a power supply and then hook the fans up normally to the Duet?



  • Dc42, how about a simple diagram that illustrates the solution without any ambiguity? You could also put it into the user guide/quick start guide. It will save you time in the long term, having to answer the same basic questions over and over again. Not everyone is electronics-savvy. I know I am not. 🙂


  • administrators

    @rkrammes:

    Sorry, I have read some other posts about this but I still don't feel confident enough yet. I would like to run all of my fan's at 12v with everything else at 24v. I have a buck converter but I would rather use one of these little 12v 5a power supplies. So DC42 said, "…if all your fans are 12V, then you can remove the V_FAN voltage selection jumper, connect the +12V output of the buck converter to the centre pin of the V_FAN voltage selection block, and connect the fans as normal." So I just remove this jumper and connect the + to the center pin. Nothing with the ground? One wire out of a power supply and then hook the fans up normally to the Duet? https://dl.dropbox.com/s/klnuf4p1kt5z3fz/IMG_0086.jpg?dl=0

    The negative side of the 12V PSU output will need to be connected to the negative VIN terminal.



  • Does this help.

    The first is using a buck converter (or 12v PSU) to supply the central pin on the VFAN jumper block. The fans are then attached normally. Please note this is an OR diagram use either the buck converter OR the separate 12v PSU.

    This next one is if you want to use a buck converter to run 1 of your fans from a different voltage and leave the others running from either Vin or 5v (via the VFAN jumper which in this scheme you do not adjust). Power the buck converter from main PSU set the voltage you want 12v/5v etc.. then ground the fan back via the fan header of your choice which allows PWM.

    If someone would like to do a nice version feel free.



  • Thanks, and again sorry for asking something that has been answered multiple times. I realized it was a bit of a tedious question when I asked it. This isn't my first reprap and isn't my first electronics project but it is my first $160 control board so when something is a little out of the bounds of common sense (to me) I want to be very careful. When I think of electrical circuits I think of loops. Diagrams are easiest for me to get my head around this type of thing if you wanted to head off future cowards. 😉



  • No worries it's not that obvious.

    I'd suggest having a system where each fan header could be connected to either the 5v rail, a new 12v rail that could be added for 24v users and the main Vin (often 24v). But there is not enough real-estate on the board for the extra 12v reg, and the jumper block to configure it all. And there is a presumption that we will all go out and buy fans of the same voltage which we probably should, but I think users like to use the parts they have lying around or the parts that have proven to be reliable they remove from their old machine when building their new one. I certainly do.



  • @dc42:

    The negative side of the 12V PSU output will need to be connected to the negative VIN terminal.

    Which VIN? The green connector on the side of the board? Is there any chance of damaging the board if the fans are not hooked up properly? Can we have a diagram which shows all connections, without the "OK, I think I know how to do it". This board is way too expensive to screw around with it.



  • All that is meant here is connect the negative to your PSU negative wherever you want to. You can use the -ve Vin terminal block on the duet, or a spare connector on your PSU if yours is the type with multiple connectors on it, or you can get a fuse box and connect accessories individually fused like in a car, if it makes you feel better.

    It is an expensive board but then if this type of thing is not very comprehensible it might be wise to do a bit more research before undertaking a build. A basic grasp of how it works and what is a good idea and bad idea is a requirement when building a 3D printer. Get a clone ramps/mega and build it first, if you fry that its only £20. If it works transplant the duet in, there is not much that isn't a straight swap.

    The schemes I diagrammed above work, the only question was about tying the grounds of the 12v independent supply and 24v supply as its the only scheme I have not personally tried, the others are configurations I currently have running. It seems David has answered that one so I've updated the diagram.



  • Sure, but your diagram does not specify the details of the connection for negative buck converter terminal. It looks looks like an open circuit. Simon, I don't really have a great problem with any of this. All I'm saying here is that a graphical information such as complete diagrams or annotated pictures do not leave room for any interpretations, because interpretations are those nebulous things that can cause a lot of smoke. The inconvenience and upset will be just as great regardless whether the board was $20 or $160. Costs are relative. Duet is sold as a mainstream board, and as such it should offer instructions for all types of customers.



  • That's because the buck converter output doesn't need to go anywhere, the ground is tied in the buck converter between input and output.

    I've another thread about fans in the hardware wishlist section, it seems duet3d's presumption is we would buy correct/same voltage fans not adapt various fans at different voltages. But that's what we want to do. If there was a clever way of having multi voltage fans then it would be worth considering.

    I'd happily liase with Tony about making a better version of these diagrams and putting them on the wiki.



  • @DjDemonD:

    It is an expensive board but then if this type of thing is not very comprehensible it might be wise to do a bit more research before undertaking a build. A basic grasp of how it works and what is a good idea and bad idea is a requirement when building a 3D printer. Get a clone ramps/mega and build it first, if you fry that its only £20. If it works transplant the duet in, there is not much that isn't a straight swap.

    I think your diagrams are good but I have to kind of disagree with what you are saying here. First, this issue is pretty specific to the Duet. Second, I have built 2 repraps and an MPCNC as well as lots of other projects like a laser for the mpcnc, a custom grow light with mixed high wattage COBs…etc. I am the guy in my circle people come to for this kind of thing but the cost of this board along with the relatively small userbase and therefore smaller amount of information available is plenty of cause for hesitation when going beyond the basics IMO. I think the forum is excellent and DC42 is amazing. The wiki is extensive but the vocabulary is a bit too technical sometimes and more graphical examples would go a long way. Also, there is very little available on Youtube. Probably a good opportunity for an aspiring Youtuber.



  • @DjDemonD:

    ..the buck converter output doesn't need to go anywhere, the ground is tied in the buck converter between input and output.
    .

    Finally. 🙂 The information I wanted to have. If an output doesn't need to go anywhere, then have it annotated on a diagram, a note exactly like the one above, but do not leave any blanks. Avoid ambiguity, especially where electricity is concerned. No broken hardware, no additional cost and inconvenience. Everyone is happy.

    Fans are different. They are the most important bits of kit for safety reasons. Given the choice of voltages, numbers of wires etc a better support for fans in hardware and/or documentation is important. It becomes a selling point as well.



  • @ect2:

    Fans are different. They are the most important bits of kit for safety reasons..

    I'd put ELCBs and even fuses above them.. And AFIK no fan failure on a 3d printer should result in anything worse than a over temperature event and a failed fan. Possibly a load of ground filament and a hideous blockage if it's the cold end fan.



  • @rkrammes:

    @DjDemonD:

    It is an expensive board but then if this type of thing is not very comprehensible it might be wise to do a bit more research before undertaking a build. A basic grasp of how it works and what is a good idea and bad idea is a requirement when building a 3D printer. Get a clone ramps/mega and build it first, if you fry that its only £20. If it works transplant the duet in, there is not much that isn't a straight swap.

    I think your diagrams are good but I have to kind of disagree with what you are saying here. First, this issue is pretty specific to the Duet. Second, I have built 2 repraps and an MPCNC as well as lots of other projects like a laser for the mpcnc, a custom grow light with mixed high wattage COBs…etc. I am the guy in my circle people come to for this kind of thing but the cost of this board along with the relatively small userbase and therefore smaller amount of information available is plenty of cause for hesitation when going beyond the basics IMO. I think the forum is excellent and DC42 is amazing. The wiki is extensive but the vocabulary is a bit too technical sometimes and more graphical examples would go a long way. Also, there is very little available on Youtube. Probably a good opportunity for an aspiring Youtuber.

    I agree that perhaps some of the documentation should be a little more accessible. But being an expensive high end board it isn't really marketed at the less experienced, and I would guess fewer people who are less experienced buy one.



  • @DjDemonD:

    I agree that perhaps some of the documentation should be a little more accessible. But being an expensive high end board it isn't really marketed at the less experienced, and I would guess fewer people who are less experienced buy one.

    I don't see why being high-end should make it less accessible. It's not like the RAMPS board is really a simple solution. It's just cheap. I would think a more expensive product should be easier to use. Just to be clear really like the Duet so I don't mean to bash it or the makers it's just that DC42 wouldn't have to put so much time into the forum if things were handled a little differently.



  • I agree that perhaps some of the documentation should be a little more accessible. But being an expensive high end board it isn't really marketed at the less experienced, and I would guess fewer people who are less experienced buy one.

    Duet targets the DIY crowd. That means everyone who chooses to buy it. Being an expensive, high end board it should have better documentation. DC42 does a great job fixing bugs and developing new features. What is lagging behind is user manual. There have been several comments made on this forum about the WIKI side of things but nothing that I can see has been done to address them. Is it just too hard?


  • administrators

    The documentation is being migrated to a better platform, which will make it easier to improve.



  • Thanks DC42



  • Sweet!



  • @djdemond I know this an old post, but its the one I need, and in particular the diagrams you posted before the forum was moved over to the new format, which it clearly did not take the posted pictures with it. Is there any chance you could repost them, please?


 

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