Welcome! Log In Create A New Profile

Advanced

New RAMPS design

Posted by MrAlvin 
Re: New RAMPS design
January 29, 2019 04:35PM
If you Like i now have a new Oscilloscope should have moste of the componments here, and can have a look on the PCB
Do you have two ore more sided PCBs? is ther a repositorry I havend found one
Re: New RAMPS design
February 04, 2019 01:49PM
i could do some testing wih arduino mega tmc2130 and my new oscilloscope:-)
Re: New RAMPS design
February 06, 2019 10:07AM
Quote
kabelfrikkler
If you Like i now have a new Oscilloscope should have moste of the componments here, and can have a look on the PCB
Quote
kabelfrikkler
i could do some testing wih arduino mega tmc2130 and my new oscilloscope:-)

Hi kabelfrikkler,
thank you, that would be great.

Quote
kabelfrikkler
Do you have two ore more sided PCBs?
I use double sided PCB. As one of the original design goals were to keep it simple and low cost.
But perhaps the oscilloscope will show us that improvements are needed.

Quote
kabelfrikkler
is there a repository I havend found one
There is no repository - yet.
From the start I knew that I might be quite slow with this development, and I knew that several iterations would very likely happen, and I did not really want to have to try to deal with several preliminary designs.
I also wanted to wait with the release, until the design were in such a state that I were happy with it. Meaning that it did not have any faults, that I would consider serious faults.

So for the few people who have so far done some testing, I have simply shared the design files with them only.
And I hope they will eventually eliminate the early versions, and replace them with the final version 1.0 (or as I hope the 1.7C will be) - and I intend to assist with this elimination process, by sending them the updated (and final version).


I think I already have your address, so I will send you a pcb later today.
As I still only have the version 1.7B as PCB, this is what I will send you, and once I get the 1.7C, then I can send you one of those. okay?

Or would you rather want to wait until version 1.7C?
Re: New RAMPS design
February 27, 2019 04:16PM
I looked through the thread and I can't find exactly what changes 1.7C entails. But given I made this mess attaching just two TMC2130's to my board, I'm very interested in RAMPS 1.7! Definitely interested in testing my own board once the design stabilises.
Re: New RAMPS design
March 03, 2019 09:45PM
Quote
RX14
I looked through the thread and I can't find exactly what changes 1.7C entails.

Hi RX14,
there are about 35 minor or major differences between version 1.7B and 1.7C

- The main difference is, that the board grew from 8x10 cm to 10x10 cm. And this allowed for a number of changes where a bit more space were given to sections that had previous been there, but had been rather cramped.

- Some electrical changes have been made, like: use of a resistor in series with the signal, to make some input pins 5V or 24V tolerant.

- Some solder jumpers have also been added, so it is fairly simple to use the board, not only with Mega and DUE, but also with Re-ARM or boards like the SAME70-XPLD or possibly the new "Grand Central board" from Adafruit industries.

For changes needed to be used with the Re-ARM board, there are however about 20 solder jumpers that needs attention, and the solder jumpers are VERY small, so I have found it very difficult to make cuts where they are needed. For this reason I simply made a board, where I had made all those changes in the layout software, and the board will be pre-destined, to be used with a Re-ARM board. Or any board that still have analoge inputs at the Arduino pins A13-A15.
My Re-ARM board did however only just show up today, so it will be some time before I have this part fully tested.

Other minor changes are:
- D70 and D71 are now available on the board
- there are 2 additional FAN ports, so 4-5 fans can now be controlled. Or LEDs or....
- some pin rotation has been made for A0 to A7, as these pins could potentially be used with TMC2208 drivers, as it is possible to assign interrupts to these pins on the Arduino Mega. And the current SoftSerial implementation seems to benefit from interrupts on Rx pins being available in the microcontroller.

Quote
RX14
But given I made this mess attaching just two TMC2130's to my board, I'm very interested in RAMPS 1.7! Definitely interested in testing my own board once the design stabilises.

Actually I do not think that is messy at all. Jumper wires are jumper wires, and they will always add a new layer of visual impression.
But I hear you: sometimes one just dreams of no-jumper-wire solutions :-)
Re: New RAMPS design
March 05, 2019 06:10PM
Quote
MrAlvin
Quote
RX14
But given I made this mess attaching just two TMC2130's to my board, I'm very interested in RAMPS 1.7! Definitely interested in testing my own board once the design stabilises.

Actually I do not think that is messy at all. Jumper wires are jumper wires, and they will always add a new layer of visual impression.
But I hear you: sometimes one just dreams of no-jumper-wire solutions :-)

It'll definitely be a mess with all 5 drivers as TMC2130's! My wiring harness is pretty hard to extend with more drivers.

Count me in for testing out a 1.7C PCB though, sounds fun to assemble!

Edited 1 time(s). Last edit at 03/05/2019 06:21PM by RX14.
Re: New RAMPS design
March 06, 2019 07:30AM
Count me in for testing out a 1.7C PCB. I can't imagine the fun of its assembly! and I'm actually building a customized core-XY 3D printer which I can test the design on.
btw I can build the PCB in-house for testing too.

Edited 1 time(s). Last edit at 03/06/2019 07:57AM by nimanouri.
Re: New RAMPS design
May 07, 2019 08:16PM
Hey,
I've been watching this project for a while and I'm really excited to do some real world testing on Arduino Due. I'm a software & hardware engineer and I have access to test equipment (digital scope, temperature & current probes, etc).
I can make my own board if required, is 1.7C PCB design available anywhere?
Re: New RAMPS design
August 20, 2019 05:20PM
Hi all,
sorry about the long silence. For the past 15 years, or so, I have had some health issues, but I mainly have them under control - until sometime this spring! There I was taken for a spin, down the rabbit hole, like it has not happened for many years. Oh well, life happens. These past few days, I have however again been able to, slowly, start looking into my (otherwise stranded) electronics projects. And this RAMPS 1.7 project is one of those stranded projects.


Before I completely left the surface, I did however manage to send some files to wodz69, so I hope they were found to be useful.

I have also promised to send a board to England, and I hope to be able to do this within a couple of weeks, as I have been wanting to do a through test on the 1.7C design, before sending components and boards.
Postage is unfortunately quite expensive, where I live, so it is prohibitively expensive if things needs to be sent several times.
I can basically order 10 boards, delivered from china, for the same price, as I spend for sending a 250g letter to england. No wonder many of the EU electronics stores have vanished over these past few years.
But this should hopefully be taken care of, shortly.



For now, I am however mainly laying in bed, watching a computer screen, that I have had arranged to hang over my head, while I rest in bed. Fortunately I am also able to operate a mouse, and this is mainly all what is needed, to use the primitive PCB layout software that I use.
Thus I have spent some time looking at a smaller RAMPS board. that a friend of mine has requested. He needs the board to be no larger than the current RAMPS 1.4 board. But he needs more fan control, a 12V Z-probe, and for the board to only run on a single 24V supply, and support for TMC2130 drivers (without a wire harness).

He is fine with the board only being easy to use with the Arduino Mega board (and by extension, the RE-ARM board). But I would also be very happy if it became possible to do the hardware SPI from a DUE (or even the new Grand Central), as these boards follow the newer Arduino standard of only having hardware SPI in the middle of the board, and not on pins 50-52.

Likewise I would like a volt buffer for each mosfet, as only few mosfets run optimally, from a 3V gate signal.


Before my recent health spin, a revision A, was made of this smaller board. For now, we call it the RAMPS 1.4.4 board, as it will be very much like the RAMPS 1.4 board for all the aux-ports and layout. Some things will however be simpler, like it will only have one main power connector. And yet it will also have a few extras in order to accommodate plug&play of some of the typical things that have become common to have even on simple 3D printers, since 2012.
This 1.4.4 Rev. A, is missing the hardware SPI connector, and the 12V Z-probe pins, so while I am basically stuck in bed, most of the day anyway, I have still been trying to eksperiment with ways to move things on the board around, in an effort to find a way, to create space for the SPI socket, right smack in the middle of the board, as well as finding room for an additional 3-pin header, for the Z-probe.

By the way, this RAMPS 1.4.4 board has a new wiki page here: [reprap.org]


I hope to talk to you all again soon.
Re: New RAMPS design
August 21, 2019 07:45AM
BTW, a bit of a bug on original RAMPS 1.4 is that the PSU pin tends to pull down when the arduino is unpowered, causing the power supply to turn on and get into a loop of the printer switching on and off when USB power is disconnected. This is solved by powering the arduino exclusively over USB, but that's not ideal.

Has high-Z at rest on PS_ON been considered in RAMPS 1.7?
Re: New RAMPS design
August 21, 2019 01:41PM
Quote
RX14
BTW, a bit of a bug on original RAMPS 1.4 is that the PSU pin tends to pull down when the arduino is unpowered, causing the power supply to turn on and get into a loop of the printer switching on and off when USB power is disconnected. This is solved by powering the arduino exclusively over USB, but that's not ideal.

Has high-Z at rest on PS_ON been considered in RAMPS 1.7?

Hi RX14,
I have not been aware of this issue, as I have (somewhat strangely) not been in contact with 3D printers that used the power-on function for the PSU. Well, not since 2011 anyway. Back then I did some testing and ended up frying several D12 ports on some Arduino Mega's!
I found that it was easy to accidentally to get a 12V wire to touch the D12 Pwr-on pin, so I stopped using/testing this function.


At a later date, I got more familiar with mosfets, and simply decided to always add a mosfet in the mix, as this would help protect the Arduino pin from user error, while fiddling with wires.

Using a mosfet to control the power-on signal of an ATX power supply, does however reverse the logic in the software. So I have made some additions in my test/development version of the Marlin firmware, and this inverted logic option should eventually become integrated into Marlin, and become a definable option in one of the configuration files.
The way I have currently named defines etc., are however not generic enough, so it will need some work, before it is pull-request worthy.


So for the RAMPS 1.7 board, the status of the Arduino pin, for having the power supply be OFF, is actually Low. And a pull-down resistor is already being used at the gate of the mosfet.

I do however, just now, realize that I have not made that resistor a strong pull-down (as is needed when using a DUE). So this has now been changed. It used to be marked as 100K, but should rather be marked as 4K7.


So thank you for bringing this issue to my attention.

Edited 1 time(s). Last edit at 08/21/2019 01:42PM by MrAlvin.
Re: New RAMPS design
August 21, 2019 01:52PM
Marlin already supports inverting the power supply pin. Just set POWER_SUPPLY to 2 (on Marlin 1.1.x) or set PSU_ACTIVE_HIGH (on current bugfix-2.0.x) to use active high to enable the power supply.
Re: New RAMPS design
August 21, 2019 02:11PM
Quote
MMcLure
Marlin already supports inverting the power supply pin. Just set POWER_SUPPLY to 2 (on Marlin 1.1.x) or set PSU_ACTIVE_HIGH (on current bugfix-2.0.x) to use active high to enable the power supply.

Ah, thank you. Good to know, that it has been updated since I looked at it many months ago.

So many things have constantly been changing/updated on bugfix-2.0.x over these past months, where I have been out of the loop, so I will probably be needing to basically start from scratch on firmware issues again.
Re: New RAMPS design
August 21, 2019 02:43PM
The setting of POWER_SUPPLY on 1.1.x has been available since I started using Marlin about a year and a half ago. However, it's not well documented - option 1 is just described as "ATX" and 2 as "X-Box" but they really just mean active-low and active-high. The change from POWER_SUPPLY to PSU_ACTIVE_HIGH was only about a month ago, however.
Re: New RAMPS design
September 05, 2019 12:28AM
Just a short update.

I have fallen for the 1.4.4 board. For one, I like the form factor. It is such a cute small board - compared to the 10x10 cm boards.


The board started out as:
- 24V only
- TMC2130 SPI driver select via PCB jumpers. No more SPI-wire-mesh floating over the Stepper drivers
- two additional Fan mosfets.
- stay the same size as the original RAMPS 1.4 board (or very close to it)


And now it includes:
- HW SPI connector following the Arduino standard (in the middle of the board). So it is no longer necessary to stick to SW SPI for newer Arduino controllers, like DUE and Grand Central.

- Z-probe connector where 12V or 24V is available, and the signal to the MPU will still not be fried, so it is safe to use with both 5V and 3V controller boards.

- the CS pins (for TMC2130 stepper drivers) are brought out to Aux-4, to pins that are NOT used by the RRD LCD options. So neither Aux-1, Aux-2 or Aux-3 pins are taken up, to control TMC2130 stepper drivers, via SPI.

- PCB traces that can now cope with the Amp loads, if the power supply is only 12V, and not 24V

- 20A rated, 7.62mm screw connector for Power and Heated Bed connectors. Again, something that was a requirement, if one were to use a 12V power supply, on a single power connector.

- improved PS_ON control, using an "open-collector" design, so the signal from the 3D printers controller board needs to be High, in order to power-on the ATX Power Supply. While the Power-on-pin on the ATX power supply is still being pulled low.


Here are a couple of pictures:






Schematics are available here: [github.com]


What do you guys think?

Does this include some of the upgrades that you would want for your existing RAMPS 1.4 board?

Edited 1 time(s). Last edit at 09/05/2019 12:32AM by MrAlvin.
Re: New RAMPS design
September 05, 2019 03:54AM
I have a wish: That the electronics never run too hot.

I consider temperaturs above 60*C to be Hot and uncomfortable, and above 80-90*C to be TOO Hot.

So when a request came in, to try to make the 1.4.4 board usable at 12V power supplies only, then I knew that I had a thermal challenge on my hands.


To get a better understanding about what in the current design would work okay at 12V (and double the amperage, compared to when operated at 24V), I set out to do some measuring.
By measuring how many volts (or rather milli Volt - mV) are lost over each item in the electric path, and noting at how many amps, it is possible to calculate the resistance for that particular item, and thus also calculate how much heat - expressed in Watt (or rather milliWatt - mW) - is produced for that particular item in the electric path.


For the heat bed I listed the following items, that could produce heat, and could cause an over heating issue, that would need to be resolved, so the 1.4.4 board could also be used at 12V

Red wire (+) (power supply wire)
Connector (screw ternminal) - from the top of the connector to the bottom (that is attached to the PCcool smiley
PCB - from connector to fuse socket
Fuse (and socket) -
PCB - from fuse to wire connectror
Connector (screw ternminal)
Bed + (red wire)
Heat Bed - should get hot, and does not affect the PCB, but since we are measuring, lets get this one too. We (I) might learn something
Bed - (black wire)
Connector (screw ternminal)
PCB to mosfet (from connector to mosfet)
Mosfet
PCB to - (PCB from mosfet to - connector)
Connector (screw ternminal)
Black wire (-)

I measured this for severl boards, and with different types of screw terminals, and different mosfets. Some of the results are listed in these two pdf files.
- original RAMPS 1.4 shield: [github.com]
- the RAMPS 1.4.4 Rev C shields: [github.com]

More lists will follow, but even from these two, it has become quite clear what causes heat, with each user/design choice.

For now, I am happy with the results from these preliminary tests, because they show that my goal about staying under 60*C is very attainable. Now I just have to device a method to repeat these test, away from the lab, and while prints are being made.
But so far so good.



Some temperature examples for the 1.4.4C shield at 12.5V
Blade fuse - 50.2C
Mosfet A - 48.3C
Mosfet B - 47.4C
Buttom of PCB - 46.8C
Connector screws - 41.4C - 42.0C - 40.9C - 39.8C


Compared to the original 1.4 at 12.0V
Poly fuse - 45.7C
Mosfet - 180C
PCB - 91C - 61C


How is it even possible for the mosfet to survive at 180*C ?


I used a K-type sensor, and the 121GW EEVBlog multimeter for these temperature readings. So I do not really have any reason to doubt the measured results.
But how is it possible for the mosfet to still be operational at 180*C ?



Some pictures of the two different 1.4 boards I tested on.


Standard configuration on fuses, connectors and mosfat.


Before I knew better; fitted with the convenient Green Plug-in screw terminals. I love the easy function, but hate that it is a rather poor thermal design.
At least it is fitted with a much better mosfet (which you can obviously NOT see in this picture). And a fuse that can handle the 10A-12A that some heat beds need.



Now with more thermally optimal connectors.



Now I just need to repeat all these tests, while the hot-end also draws power. The heater cartridge I just tested drew 4A. So 48W. Is this typical? I thought that it was supposed to be only 40W.
Sorry, only registered users may post in this forum.

Click here to login