What do the LEDs represent on RAMPS 1.4?

Hey guys,

So I've built myself a RepStrap of my own design (very simular to the WolfStrap design on the wiki) and I've overcome many problems with it now and I'm pleased to say yesteday was it's first good(ish) print. The print didn't come out as well as i'd hoped (corners were not brilliant) and I think this is because my bed is far too large and I'm having difficulty levelling it. What I will do is make it smaller - just large enough to print the largest part of the prusa (if anyone knows how large that is i'd be very greatful!) as this is the printer I'd like to have (I2 - I don't like the look of I3!). Now, when the print gets somewhat intense (IE, printing the last part of a star on an object) I think the RAMPs over heats and shuts off (thanks to those PTC fuses which I'm findung useless atm). I'm trying to debug this but i'm not sure what the LEDs represent and it would be very helpful to know; the wiki merly states where to place them. The LEDs I have (all of them are lit I think) are attached in the photo . Some things to note:

* I don't currently have a heated bed, however, pronterface is registering a temperature for one?
* I'm using a very old PSU (AT not the ATX) and it only supplies 9A on 12V.
* I've made my own heat sink for the FETS, could this be causing a problem? ( photo attached)

I'd like to print this:

http://www.thingiverse.com/thing:115091

to go on my RAMPs to hopefully stop this over heating problem, however I don't see then how the fuses can limit the current if they're not allowed to heat up correctly? I've read many people have removed them and introduced in line fuses which I think could be a possibilty.

Anyway, I seemed to have rambled! I'm essentially asking if it's bad to have all the LEDS lit (the red one has only recently come on) and what they mean and also some guidence on the ossible over heating problem.

Cheers guys!

~Injection

PS, on a side note, I'm assuming you can debug problems with a printer by looking at something it's printed. If this is the case what things would you look out for? I know about having your Z axis not homed correctly and getting a squashed bottom layer but what else? I've attached a photo of my first print so please express any problems

WELL... the picture is not very good but I would say you are definately extruding too much plastic.
Have you properly calibrated your ESTEPS_PER_MM?

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

I can take more if you'd like to see it at different angles, but I hadn't thought about it extruding too much plastic - i was always under the impression it was too little (I always have to manually push some through before it starts it's print or it doesn't extruder for quite sometime during the print).

I thought I had probably adjusted my E steps, I'm using sprinter as my firmware and have axis steps/mm set up as follows:

#define _AXIS_STEP_PER_UNIT {2129, 2129, 4258, 682.57513}

Unless I need to change anything else for the extruder in the firmware?

I've also drastically reduced my acceleration values - could this be a problem?

Thanks!

EDIT:

I realise my steps/mm mean nothing without you knowing my gear ratio, which I don't know either as i used some gears I found out of a inkjet printer!

Edited 1 time(s). Last edit at 07/23/2013 06:10AM by injection1337.

Reducing the acceleration is unlikely to cause a problem, increasing the acceleration can cause problems.
The steps/mm for your extruder is 682.57513.
This can be calculated by iterative measurement and calculation.

Remove your hotend such that the filament can be fed without actually extruding plastic.
Put a mark on the filament and then extrude 100mm and make a second mark.
Now measure the distance between the marks.
If your value is correct (and you are not extruding too fast and loosing steps) then this should be exactly 100mm.
If you are extruding too much then this will be more e.g. say 120mm.
Which means your current value is 120/100 of the correct value.
So CV * 100 / 120 is your NEW value, in this case 682.57513/1.2 = 568.8126
Change your firmware to use the new value and then run the test again.

This time it should be exactly 100mm!

If not calculate the new value again using NV = CV * 100 / ML; where

NV = new value, CV = current value and ML = measured length

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

I have previously done this, but I didn't think of removing the hot end and doing it that way so thanks! it'll be much more accurate now XD

Also, any ideas on the LEDs?

thanks again!

~InjectioN

You should have a fan aimed at your polyfuses.
You probably only need a heat sink on the FET that you haven't attached one to but seeing as you don't have a heated bed it won't matter for the time being.
The LED's are ..1 each for each FET circuit (D8, D9 and D10)and one for power on (I think).

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_______________________________________
Waitaki 3D Printer

Quote
injection1337
I have previously done this...

Another possible source of error would be the slicer program.
If for example you are using 3mm filament that is actually 3mm in diameter but have 2.8mm set as the diameter in your slicer program then you would be extruding 3/2.8 = 1.0714 (or 7.14% more plastic than you should be).

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

I haven't got my board with me but it looks like i have LED3 (red) LED4(green) and LED1(green) on. I think LED1 is for power, LED 4 could be for the MOSFET for the hotend but LED3 is on and I don't know why. If it's for te heated bed MOSFET, I have nothing connected so it shouldn't be on

Thanks again

Quote

Another possible source of error would be the slicer program.
If for example you are using 3mm filament that is actually 3mm in diameter but have 2.8mm set as the diameter in your slicer program then you would be extruding 3/2.8 = 1.0714 (or 7.14% more plastic than you should be).

This could be the problem, I have 3.14 set as my diameter but i'm quite confident it's almost spot on 3mm, I'll do another check later but I recall not changing this when I know it's very close to 3mm

All of the PLA that I have used has been around 2.9mm.
If yours is 3mm and you have 3.14mm set in the slicer then it SHOULD BE extruding less plastic than needed instead of more than needed as it is in your case.

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

The LEDs definitely are for the MOSFETs. If you have one on, and don't have anything connected to it, the RAMPS is supplying power to nothing. I didn't think this was possible without a thermistor.

If this is indeed the case, I'm not sure what the amperage draw would be. I would guess nothing since there isn't a completed circuit, but I'd investigate anyway. The MOSFET for the heated bed is turned on and off by the firmware in response to your G Code. Check your G Code to see if you are inadvertently turning it on. If so, then I'd check the slicer settings for temperature. Maybe something is checked that shouldn't be.

Quote

All of the PLA that I have used has been around 2.9mm.
If yours is 3mm and you have 3.14mm set in the slicer then it SHOULD BE extruding less plastic than needed instead of more than needed as it is in your case.

This is true, a quick look at my slicer program and doing the same calculations as you, with filament diamter as 3.104 it should be extruder 3.35% less plastic - correct? Either way something isn't correct here so I shall check this tonight as well as my steps/mm and I'll post what I find. On a side note, should i use 1/16 stepping for the extruder?

Quote

The LEDs definitely are for the MOSFETs. If you have one on, and don't have anything connected to it, the RAMPS is supplying power to nothing. I didn't think this was possible without a thermistor.

If this is indeed the case, I'm not sure what the amperage draw would be. I would guess nothing since there isn't a completed circuit, but I'd investigate anyway. The MOSFET for the heated bed is turned on and off by the firmware in response to your G Code. Check your G Code to see if you are inadvertently turning it on. If so, then I'd check the slicer settings for temperature. Maybe something is checked that shouldn't be.

I just looked at my photo of the LEDs and these:

[reprap.org]
[reprap.org]

And i think for some reason D9 is being powered?! Looking at the diagram on the WIKI it's for a second extruder but I don't have one? I have nothing connected to D9 so I'll crack out the DMM tonight and see what's going on!
Is it possible I've shorted the FET for D9?

EDIT//

I may wire in a fan to D9 anyway to cool the polyfuses, is this advised? I also don't currently have a fan on my hot end - is it needed?

EDIT EDIT//

You said you didn't think this was possible without a thermistor, pronterface is reconising a resistance for the heated bed. This is worrying because the magic smoke came from the RAMPs board a while back, and the only thing I noticed was my thermistor wire slightly melted. Is it possble to short T0 and T1, causeing a resistance and hence a temperature reading?

Edited 2 time(s). Last edit at 07/23/2013 10:17AM by injection1337.

Quote
injection1337
On a side note, should i use 1/16 stepping for the extruder?

Definately, if you've got it - use it! Runs quieter...

Quote
injection1337
Is it possble to short T0 and T1, causeing a resistance and hence a temperature reading?

Why guess? Use a multimeter and measure the resistance.
A short would however cause a very high temperature reading...

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

rhmorrison Wrote:
-------------------------------------------------------
>

Quote
injection1337
> On a side note, should i use 1/16 stepping for the
> extruder?
>

> Definately, if you've got it - use it! Runs
> quieter...
>
>

Quote
injection1337
> Is it possble to short T0 and T1, causeing a
> resistance and hence a temperature reading?
>

> Why guess? Use a multimeter and measure the
> resistance.
> A short would however cause a very high
> temperature reading...

Ah ok, perhaps not then. I'll test the resistance anyway - It should be infinate correct? the teperature reading of the non-existant bed is averaging 40C I think. I'll take a screen shot of pronterface tonight.

Thanks so much guys, truly very helpful!

This is my first post on the reprap forum and it's been very helpful!

Here's what you should see illuminated...(With Power connected to Ramps and USB cable connected to PC)

Click "connect" in pronterface. - no LED's should be lit (except Arduino board)
Click "Heater on" - LED1 and LED 4 will illuminate (I think these 2 led's are dedicated to the heater only)
Switch heater OFF then Switch heated bed ON - LED 2 only will illuminate. (but only if the 2nd 12v power input is connected)
LED 3 only illuminates when D9 is enabled (usually a fan)
Aim a fan at the polyfuses and connect to D9 (as you thought) - just stick it there with blu-tak or something to get you going.

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_______________________________________
Waitaki 3D Printer

Ok so I've done a lot of debugging on my printer, and if anything I now have more questions! To help others though I'll summerise my previous questions as most are now answered:

* The red LED on the top left of the board is for the middle MOSFET. This is on when D9 has power.
* The next one is for the top MOSFET which is when D10 has power. This LED is green.
* My heat sink which went across both the MOSFETs for D10 and D9 for some reason was shorting D9 and powering it (that or I've blown it).

I have the P55NF061 MOSFETS on the board, I've read they're really bad - is this the case?

This is why I had the red LED lit, I took off the heat sink and it went off. For some reason D9, with no thermistor connected and nothing connected to D9 had 2.2v across it. But now, when I turn on the hottend my 5A PTC fuse heats up instantly and turns off, even with an 80mm fan on it. I connected my fan in parallel with the PSU and RAMPS board, should I have connected it in series?
Even when I'd taken the heat sink off and the PD across D9 dropped to ~0v (it read 0.05v) my fuse still kicked in and shut it down. (I used a IR thermometer and it read around 90C)

So I went to the firmware and dropped the heater current down to 50 (from 255!) it took quite sometime to thermally cut out; which is obvious really as it takes longer to heat the fuse up (and my hotend only reched 60ish after 5mins). It's always made an audiable tone when heating, I think this is due to the PWM. I checked the voltage at the RAMPs input and it was 8.98v and the wires were hot.

What should the resistance,if any, be between the nichrome wire and the thermistor? I'm getting 5k3 - could this mean I have a blown board?

What also makes me think this is that pronterface always shows this:



I don't understand what the number means after the @ symbol but I can certainly tell you I don't have a bed themistor (I'm assuming B is for bed?). My normal thermistor is no longer working correctly either. It only increases by a few degress and if it's just sat there with no heating it reads 78C. I measured the resistance between one of the T0 pins and one of the T1 pins and it was 0.00 Ohms on 200k setting and it read 1 on 20k setting? This is why I think it's broken.

If so, I'd like to buy another RAMPs board but not one from Hong Kong, anyone know a cheap UK distributer?

sorry for the 101 questions but I'd really like to print a prusa i2!!

~Injection

EDIT//

Perhaps I need to change te pins as suggested here [forums.reprap.org] ?

Edited 1 time(s). Last edit at 07/23/2013 08:15PM by injection1337.

Waitaki, in my haste to understand what was going wrong I forgot to connect the fan to D9! I used the 12v output from my PSU, hence why it was in parallel! could this cause a problem?

I'm not sure of the consequences of paralleling your fan with the ramps input but I would not do it!
With the fan disconnected, does your fuse still shut down instantly when you switch the heater on? Sounds like a bit of a short somewhere if it does. In any case, it's the big (heatbed) fuse which is generally the one that runs too hot and needs cooling and you're not using a heat bed. I would expect the smaller fuse to handle it without cooling.
Ok, disconnect the heater wires from D10 and switch on the heater - the polyfuse should stay cold. If it gets hot, you have a short or something on your ramps board.

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_______________________________________
Waitaki 3D Printer

Yes, with the fan disconnected it still heats up instantly (unless i reduce the current to the hot-end in the firmware in which case it takes longer but does eventually shut off). I know it's definatly the smaller, 5A, poly fuse cutting out as that's the one that gets incredibly hot.

I'll disconnect the Nichrome from D10 later and try turning on the hot end to see what happens.

Cheers!

Alas some good news!

So I disconnected the heater element and told pronterface to heat up the absent heater. The LED came on, denoting power to D10, and the fuse and FET stayed cool! So with this knowledge and the fact I think my heater element is shorting on my thermistor I used some spare NiChrome wire and plugged it into where my hot end connected. Once again I told pronterface to heat it up and it did so with out the 5A fuse getting hot! the FET did get incredibly hot though but after a while it cooled down to around 45C.

My heating element got to around 195C and I turned it off quite happily. I'm still unsure as to whether my Arduino's IO pin has been burned out as I haven't got the correct thermistor in my hot end. So i'll wire up the correct thermistor, set the tables and check it out.

Thanks all for you help!

~InjectioN