Ramps 1.4 Firmware and Fan configuration

Hi guys, so, finally time for the MendelMax that I'm working on.

I've run into a little trouble. While trying to figure out how to connect my fans, and how to connect the hotend, I discovered I need a little guidance.

In the firmware, I've set the RAMPS type to '34'

// 33 = RAMPS 1.3 / 1.4 (Power outputs: Extruder, Bed, Fan)
// 34 = RAMPS 1.3 / 1.4 (Power outputs: Extruder0, Extruder1, Bed)

However, I am not using a 2nd extruder (why would I?.. I like technical stuff, not multicoloured stuff).
So my guess would be to use #33 instead of #34 (someone told me it had to be 34, but I don't think they listened very well to my explanation)

And then I found this picture somewhere on the web:


Extruder fan will work, this is ok.
Electronics fan also seems logical (I will hook up my PSU to both the 11A and 5A + and - because it has only one output, and then I will just attach the electronics fans(there are two) to the 5A wires)

But, when I select the 33 board in my firmware, don't I then have to use 'D10' for my print fan? Instead of D9 that is shown in the image?

Edited 2 time(s). Last edit at 12/24/2013 08:22AM by Ohmarinus.

No. The diagram is correct for motherboard 33. D8 for the bed, D9 for the fan, and D10 for extruder 1.

Wow, okay, that feels very illogical, in the firmware it's like 1-2-3 extruder(1) - bed(2) - fan(3) but on the RAMPS itself it's actually 2-3-1
Thanks for clearing that up! SO I will safely use motherboard 33 with the Fan on D9, bed on D8 and extruder1 on D10.

I also have a fan-splitter from G3D, do you think I can hook the main of the fan-splitter up to the 'Electronics' fan/5A input? This seems the most logical.

The print fan on D9 will have PWM I guess, so I will have to figure out how Slic3r works with that, my Sanguinololu isn't that advanced.

On the Sanguinololu I had to use a relais between the bed and the board so the relais (or relay) will get hot and the Sanguino FET will not burn out. On Ramps this is not a problem right? My FET also has a cooler connected to it and 2x 50 or 60mm fans blowing on it to keep it cool.

Quote
Ohmarinus
Wow, okay, that feels very illogical, in the firmware it's like 1-2-3 extruder(1) - bed(2) - fan(3) but on the RAMPS itself it's actually 2-3-1

The comment text in the firmware has no real relation to the order of the outputs, just what type of outputs are configured, which is quite annoying.

I'm not sure what a fan splitter is. Fans are simply motors, and all you need to do is splice the wires together, positive to positive, ground to ground, in parallel, and one output operates two fans. I don't think you'll have any issues operating 2 or 3 small fans. If in doubt, add up their amperage draw along with everything else on that circuit and make sure you don't exceed either the fuse on that circuit, or the capacity of the PSU.

Okay, I'll crimp some wires together so they fit into the 5A input (however might as well be the 11A input since it's from the same PSU, but I'll use the 5A).

For the fan splitter, it's this one:
[gadgets3d.eu]

Here's the manual:
[gadgets3d.com]

However, they connect the complete splitter to the extruder fan output.


Oh, btw, considering the image, I'm switching out extruder and electronics fan because the electronics fan I'm using already has connectors that fit great on the fan splitter and the extruder fan has open ended wires now




One more thing, I am having all five stepper drivers in place, X, Y, Z, and E0. However, there is a fifth stepper driver in my Ramps, E1, I guess I'll have to take it out because there will be no motor connected right? I heard that putting the 12V PSU on the Ramps when you don't have any motors connected will fry the stepper drivers?

Edited 1 time(s). Last edit at 12/25/2013 06:08AM by Ohmarinus.

I don't know about having a driver without a motor. Certainly its not necessary so it would probably be better to keep it in a drawer as a spare.

What I do I know (from personal experience) is that if you connect or disconnect a motor while the power is on, or if you plug in a driver to I circuit that is on, that you have a high likelihood of destroying that driver. I would imagine its also not a good idea to remove a driver from a live circuit.

If you connect the fan to the power input on the Ramps board, you run a good chance of melting the terminals on the Ramps. Why? - they are not designed for multiple pieces of wire. They are designed to take a single piece of (preferably solid) wire and clamp onto it. With multiple pieces of wire their clamp approach does not work well long term. Much better to connect the fan and other 100% on devices to the power supply a different way.

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uncle_bob
If you connect the fan to the power input on the Ramps board, you run a good chance of melting the terminals on the Ramps. Why? - they are not designed for multiple pieces of wire. They are designed to take a single piece of (preferably solid) wire and clamp onto it. With multiple pieces of wire their clamp approach does not work well long term. Much better to connect the fan and other 100% on devices to the power supply a different way.

Hi uncle_bob, you mean that it might cause arching on a small scale? I would've crimped the wires together anyway if I would connect two wires to one power output!

But, I have decided to take motherboard #33 in Ramps, so I have hooked up the 100% on fan (extruder fan) to D9, and nothing else is on D9. The fan splitter is now on the 12v aux, where it says 'extruder fan' in the above image, the fan splitter has small connectors where I have hooked up the electronics cooling fans to. 2x 50mm fans that cool the stepper drivers.

When I get an extra set of connectors (I am out of connectors!) I will hook up the print-cooling fan to D9 and then will switch the 100% on fan to the fan splitter since it will give me 100% all the time.

Tomorrow I will clean up the wires of the machine and start test-running it I hope everything is ok with the wiring. Measured everything, and all seems ok, so tomorrow will hook up the 12V PSU and fingers crossed let's hope there's no blue smoke!

Got it to work

First run!
[youtu.be]

When you connect multiple pieces of wire with one of these screw terminals, it tries to crush the wires into a solid mass. Since they are not perfect, it does not crush them completely. As things move (printers vibrate a bit) the wires re-seat themselves. They do so to achieve the lowest energy state. That's going to be the minimum crush point. The net effect is that they loosen up with time. Loose connections are high resistance connections. You do not have the contact surfaces fully engaged. High resistance means higher temperatures. We are already running the terminals at or above their maximum ratings. Any increase in temperature is not a good thing. As the terminals melt, they stretch. That loosens the connection even more. Thermal runaway is the proper term for the "smoke comes out of it" event that flows ....

Okay clear, thanks, but I imagine that because I crimped the copper wires together this will not happen. The crimped part is inserted in the terminal so the wires are already crushed together and clamped on by the screw terminal.

You have moved the point of failure a bit with the crimp, but have not removed it. Unless you have a very good crimping tool and the right crimp fittings, there's still a chance of the wires working loose over time. Solder is a better approach in this case, but it's still not ideal. Crimps are designed for a range of wire sizes. A fan wire is likely #30 and the power wire should be around #16. Most crimps are able to handle a range of 4 to 8 wire gauges depending on their design.

Ah yes, I have around 5 different flavours of crimps, ranging from .75mm to 2.5mm

I've been avoiding solder on most contacts because I had been warned about corrosion.