RepRap Mega Pololu Compatible Shield - RAMPS (HC3DPR0002)

[admin]

Description:

RepRap Arduino Mega Pololu Shield, or RAMPS for short. It is designed to fit the entire electronics needed for a RepRap in one small package for low cost. RAMPS interfaces an Arduino Mega with the powerful Arduino MEGA platform and has plenty room for expansion. The modular design includes plug in stepper drivers and extruder control electronics on an Arduino MEGA shield for easy service, part replacement, upgrade-ability and expansion. Additionally, a number of Arduino expansion boards can be added to the system as long as the main RAMPS board is kept to the top of the stack.

Version 1.4 uses surface mount capacitors and resistors to further cover edge issue cases.


Features:

• It has provisions for the cartesian robot and extruder.
  Expandable to control other accessories.
  3 mosfets for heater / fan outputs and 3 thermistor circuits.
  Fused at 5A for additional safety and component protection
  Heated bed control with additional 11A fuse
  Fits 5 Pololu stepper driver board
  Pololu boards are on pin header sockets so they can be replaced easily or removed for use in future designs.
  I2C and SPI pins left available for future expansion.
  All the Mosfets are hooked into PWM pins for versatility.
  Servo style connectors are used to connect to the endstops, motors, and leds. These connectors are gold plated, rated for 3A, very compact, and globally available.
  SD Card add on available -- Available now made by Kliment - Sdramps
  LEDs indicate when heater outputs on
  Option to connect 2 motors to Z for Prusa Mendel

Connections:



Schematic:



FAQ:
What is the additional diode supplied with this board for?
The diode (D1) is an optional component that can be fitted depending on what supply voltage you are applying to the ramps shield. Without the diode fitted you will need to power your mega separately i.e.USB cable or adapter. With it fitted to D1 the ramps shield will power your mega from its supply. However, please be aware, when fitted you must not power your ramps shield with a supply greater than 12V otherwise you may damage your mega.

Manual:

RAMPS_1-4manual.zip

[ILYBTodd]

Are these Hobby Component built boards?
Main concern I'm reading about elsewhere for the Chinese RAMPS boards is the quality of the mosfets.
Please comment on specification of power mosfets.

[ILYBTodd]

What amperage are the Power green connectors rated for?

[ILYBTodd]

What voltage are the poly fuses rated at?

[andrew]

Current stock is fitted with a 16GF1100 (MRF1100) and a 30UF500 (MRF500). The 16GF1100 is rated at 16V max, and the 30UF500 is rated at 30V max.

The power terminals are rated at 12A.

[ILYBTodd]

Hi Andrew,
I picked up a 5V fan for a new hot end and I'm curious where best to connect to the RAMPS board if there is a suitably rated 5V pin like those on the servo rails or the one near the poly fuses that could be used instead of having to step down the 12V supply currently used to power the fan. Amperage requirement is low, 0.5 amps or less if I read the data sheet correctly.
Any suggestions?
Todd

p.s. Just noticed that AUX 2 and AUX 3 have 5V pins that might also be an option.

[andrew]

I'm curious where best to connect to the RAMPS board if there is a suitably rated 5V pin like those on the servo rails

The 5V from the servo rails is supplied by an external 5V PSU which you'd connect via the 3 pin header near the shields reset button. So without an external 5V supply connected you won't get 5V on the servo pins I'm afraid.

p.s. Just noticed that AUX 2 and AUX 3 have 5V pins that might also be an option.

You can however take 5V from any of the headers that are labelled VCC (not 5V) in the schematic but bear in mind this comes from the 5V regulator of your Arduino. If your fan is taking that much current, which to be fair seems a lot for a 5V fan, then it may or may not be a bit too much power when taking into account anything else the Arduino may be powering.

The best rule of thumb is when it's all running, and assuming you can get to it, is to touch the 5V regulator on the Arduino. If it's so hot that you can't hold your finger on it then it's probably being overloaded and you'll either need to power the fan from an external 5V supply or replace it with a 12/24V fan depending on what everything else is running off. If the regulator is just warm then it's probably ok.

[ILYBTodd]

Thanks again!
Ah the three pin next to the reset is an input not an out then.
To get up and running I will use the supplied step down adapter and plug into the 12V fan pins just to be safe.

Todd

p.s. fan draws 105 mA per the data sheet. This might be more in line.

[andrew]

p.s. fan draws 105 mA per the data sheet. This might be more in line.

Ah yeah that's more like what I'd expect. You may be ok running it from the Arduinos supply if it's that low then.