Ramps 1.4 has two power inputs, how to connect?

Hi guys, my Ramps has an input for 11 Amp and one for 5 Amp.
It is a Ramps from the Gadgets 3D kit.

However, my PSU just has one output (that I know of). Also, this PSU has enough power to supply more than the combined 16 Amp.

Can I just split the + and - into two + and - ??

Also, the power connector on the Arduino Mega is in the way, would I ever need this for anything? If it is never used, then I am considering removing it because the Ramps doesn't fit entirely straight onto the Arduino Mega now.

Edited 1 time(s). Last edit at 08/26/2013 10:58AM by Ohmarinus.

Hey Ohmarinus, i suggest following this wiring guide. Atleast that's how I did it and it worked for me

Hey thanks, thats the problem. My PSU has only one 12V output, but can handle way over the required amps.

With the Sanguino I have it worked fine, but my Ramps has one 11amp and one 5amp input..

I am confused how to solve this.
This is the PSU:
[www.ebay.com]

Quote
The bottom pair of connectors marked 5A power the stepper drivers and Extruder heater/fan (D9, D10). The source should be rated a minimum of 5A.
The pair of connectors above marked 11A power a Heated Bed, or other output (D8). The source should be rated a minimum 11A (if both power rails are connected to the same supply it should have a minimum rating of 16A).

Does this mean that I can hook up the single rail of the PSU to both of the inputs? I'm just going to go ahead with this, as it looks like it is possible. Splitting the PSU cable just before it goes into the RAMPS.

Furthermore, I still don't know if I can remove the power-connector plug from the Arduino Mega. Do I need it for anything?

Edited 2 time(s). Last edit at 08/28/2013 12:11PM by Ohmarinus.

Yes, you can hook the power supply to both inputs.

Hint: As the Heated Bed draws the most power, connect your power supply direct to the 11A input. Then use smaller pieces of wire to jump the 11A input to the 5A input. Doing it the other way around leads to lots of current being put on those small pieces of wire, which is sub-optimal.

Re: Arduino power connector:

It shouldn't be needed in your situation. If you run 12V, you will either be:
- powering the Arduino via the diode on the RAMPS board.
- powering the Arduino via the USB cable to your PC.

That said, it shouldn't physically interfere with the RAMPS board, so I'm wondering why you want to remove it?

Thanks for your reply, I will use the same gauge wire for both the 11A and 5A input.

Too bad both Thermistors I had turned out to be broken so now I have to wait another two shitty weeks before I can finally start printing... Argh.

The power connector is physically interfering with the Ramps board. On the Ramps, the power connector has long pins that protrude on the bottom and hit the power connector, shall I take a picture?

I bought it from G3D.

If that's the case, then sure. I'd personally trim the pins off closer to the bottom of the board (using a pair of side cutters) and only remove the connector if there is still interference after that.

Okay I have cut it off and it works now. I did however damage a trace on the board, but it looks still like a closed connection.

I keep getting a mintemp/maxtemp triggered error. I have tried two thermistors, but turned out both were broken.

How can I measure my thermistors to check if they work?

Measure the resistance with a multimeter. At normal room temps, they should be near the max value of resistance (eg: close to 100K if they're 100K thermistors). They will have a lower resistance at higher temps.

What sort of thermistors are you using? I've found that axial thermistors are a lot less fragile that the bead style. The axial ones are a little cylinder with a lead out each side. This means your heater block needs to have a hole all the way through the size of the thermistor.

I use ceramic glue (eg: makergear ceramic heatcore adhesive - liquid glass or some other sodium acetate based adhesive is good too). I put the tiniest amount on the glass part (use the point of a fine needle to apply it - you only want to get glue on the glass part, NOT on the ends or the wires, so you don't need much at all) and use that to stick it in the hole. The diameter of the thermistor and the hole should be very close, but the hole needs to be the tiniest bit larger, otherwise the glass part of the thermistor may shatter when you insert it, or when it heats up (usually the first time). Ceramic glues take a while to set, so you should avoid bumping/moving it for at least an hour, maybe longer. I'd leave it 24 hrs before use. You can raise the temp a bit to make it cure quicker (eg: heat it a bit with a hot air gun), but it still takes a while to set. you need to cover the leads with decent insulation too, to stop them shorting to the heater block.

Edited 1 time(s). Last edit at 08/30/2013 09:17AM by Cefiar.

Hi, yes, this is actually my second printer I'm building and I've never had these problems with my first one. I indeed did measure the resistance, but all the broken ones returned zero.

The ones that worked actually reported resistance

So I hope the thermistors that will be here in a few weeks will work

doomstrike Wrote:
-------------------------------------------------------
> Hey Ohmarinus, i suggest following this
> [url=http://78.47.92.212/i3_documentation_pics/09-
> wiring.md.html]wiring guide[/url]. Atleast that's
> how I did it and it worked for me


Dude are you serious? I just wired mine up exactly like that with my new ramps board and instant magic smoke!

Vortex87 Wrote:
-------------------------------------------------------
> doomstrike Wrote:
> --------------------------------------------------
> -----
> > Hey Ohmarinus, i suggest following this
> >
> [url=http://78.47.92.212/i3_documentation_pics/09-
>
> > wiring.md.html]wiring guide[/url]. Atleast
> that's
> > how I did it and it worked for me
>
>
> Dude are you serious? I just wired mine up exactly
> like that with my new ramps board and instant
> magic smoke!

That does not necessarily mean that the wiring guide is incorrect!

Really, before connecting any newly wired piece of electronics it is essential to check there are no shorts across power rails. Pretty much any other fault it is still safe to plug it in and debug when powered. But a power short or reverse connection nearly always breaks something.

If you can't afford a bench PSU with an adjustable current limit, then at least a $10 multimeter can be used.

I do have a multimeter and my power was an even 12 volts. I don't have a heated bed, which I narrowed down as the cause. The smoke came from the chip nearest the power jack on the mega. I took out the 11A plug and tested it again and things were fine..

Vortex87: Sounds like you have a short on the heated bed side of your board. There's been a few reports of bad boards and/or solder bridges on the bottoms of some RAMPS boards from cheaper vendors. You might want to check that.

Also, what are you referring to when you say chip? You also said the chip on the Mega, which if you really did mean the Mega implies that you've burnt out the regulator on the Mega, which is what is used to provide power to the Mega from the RAMPS board or the DC socket. Without this, you can only power the Mega via USB. Note that if you fried the regulator, it sounds like you've got the voltage to the 5A side hooked up backwards, which would fry more than the regulator (all the stepper drivers, etc).

Are you quite sure you got the wires the correct way around?

If you meant something on the RAMPS board, there aren't any IC's directly on the RAMPS board, which IMO is the only word "chip" really refers to. There are chips on the driver boards, but the driver boards are NOT connected to the heated bed input.

I am absolutely certain I have all the wires hooked up correctly voltage wise. Regular standard 12V off a PC power supply, yellow for positive, black for ground or neg. Well yea, that sounds about right about that particular component, it smoked instantly. So, it just so happened I had a spare Arduino that I was saving for a future project. I swapped it out once I made sure the problem was fixed. I only hooked up a single yellow and black wire to the 5A + and - (Like all the other diagrams show) Now I have the X and Y axis working smoothly, the mechanical endstops all hooked up correctly. For some crazy reason the Z axis motors won't move at all, no movement whatsoever since I turned it on. The extruder motor also works well. The thermistor and hot ends aren't being detected, but I might have a wire crossed in my thermistor. I can't figure out what it is either, I swapped out a known working stepper driver and still nothing...

Regarding Z:
Check the output of M119 regarding your end stops. I helped debug a problem last night where all the endstops were inverted, so Z min and Z max were both triggered, so it wouldn't move in either direction.
Check that you're giving the motors the right amount of current (trimpot on the driver). The 2 Z's in parallel can sometimes cause issues. For debug purposes, try a single Z at a time if you can, or put one/both Z's on something like the Y and the Y on the Z, and see what happens. It could be a bad solder joint on the RAMPS board, or a bent pin, bad driver socket, etc.

So, if i'm correct, the 11 and 5 amp can be attached to the same rails as long as the total that the psu can deliver is above 16 amps?

Correct. I would aim a little higher than 16A, as those PTC fuses don't always trip at their marked current limits (depends on a lot of things, like ambient temp, how well they're cooled, etc). Also, while a PSU may be marked as 16A, you may find that in fact it can only provide say 15A, as vendors can sometimes be a bit optimistic on what their PSU's are capable of. Better to leave yourself a bit of wiggle room.

eg: I have a 24V / 16.67A rated PSU that I can only reliably get 15A out of.

Alright, I will be putting them both on the same PSU output then

The PSU is rated 24 amps, and I have made a nice 80mm ø hole in the casing and put an 80mm fan to cool the inside and blow cool air on the cooling element inside the PSU.

I received a batch of ten new thermistors this week, so I can finally finish my work on the printer!

This is useful [reprap.org].

I think he put it on a little wrong. The 9V connector on the Mega was getting in the way with mine, but when I separated them and put them back together it worked fine. I would just try to evenly press the RAMPS onto the Mega and take it off and try again if it doesn't work.

Hi,
I am facing a problem that, when I connect the USB cable to Arduino mega 2560 r3 assembled with ramps 1.4 and Reprap discount full control lcd display. I can connect the printer in REPETIER HOST.
But to print as soon as I switch on the 12V Power supply communication disconnects. and could not connect the printer.
Same issue is faced while uploading Marlin software through Arduino software. I have tried 3 mega boards. Can anybody help me solving this issue?