Summary

In RAMPS 1.4, the resistors and capacitors are now surface mount to fit more passive components. This does add another set of steps to assembly, but we stuck with larger sizes to make it fairly painless.

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.
USB type B receptacle
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

Safety Tip

even at just 12 volts - you have to take basic, common sense precautions to avoid fires. Just in case these fail, test your workshop smoke detector. Got no smoke detector? Get one!

Inspection

Stepper Driver Boards

- Jumpers need to be installed under each stepper driver:

 jumper   Yes/No  step size
 1     2    3
 no   no    no    full step
 yes  no    no    half step
 no   yes   no    1/4 step
 yes  yes   no    1/8 step
 yes  yes   yes   1/16 step

For now the default is 1/16 micro stepping (all jumpers installed under drivers)

Cut the pin headers to 8 pins long so that they fit each side of the stepper driver.
Insert the pin headers into the sockets on RAMPS
Fit the stepper drivers onto the pin headers and solder. Only heat each pin for a few seconds at time to avoid damage to the socket.
- Glue the heatsink (if used) to the top of the A4988/A4983 chip using the provided pad of double-sided adhesive.

Opto Endstops

- Cut the 26awg 3 conductor cable into 3 length.
- Note: you may want until you've built your machine to cut the cables to the perfect length.
1. - crimp and solder a female connector to the ends of each wire. (solder not necessary with proper crimp tools)
- use the 2.54mm 1x3 housing.
- Connect at least the minimum endstops.

RAMPS End
SIG (S)
GND (-)
VCC (+)

Endstop End
VCC (+)
SIG (S)
GND (-)

Mechanical Endstops

The recommended firmware will provide a configuration to use mechanical endstops with just two wires.

Find the area labelled "endstops" in the upper right corner of the board and for each of the X, Y, and Z pairs of pins (label should be below each set) do the following:

Connect S (top row, labelled to the left) on RAMPS to NC on the switch.
Connect GND on RAMPS to C on the switch.

Note: The latest firmware such as Marlin seems to use NO as the default pin on the switch. Otherwise you may need to invert the endstops in the firmware. You can use M119 to check your endstops status.

Put the connectors on the motor wires

- solder a female connector to the ends of each wire.
- use the 2.54mm 1x3 housing.
- Shown is the type used for servos in RC projects. See Stepper Motors for info on motors.

Thermistor Wires

Use a 2 pin 0.1" connector to terminate the thermistor wires.

- Connect the cable so the 2 wires go to T0
Connect the 2 heater wires to D10 (E0H on older boards) and the + connection above it.
- If changing to an unverified firmware it is best to verify heater circuit function with a meter before connecting heater to prevent damage to the extruder.

Pololu carriage

File:PololuExample.JPG

This section assumes you are using Pololu, but there are other options. Insert two 1x8 pin headers into the board. If you bought a kit with one 16 pin header, simply cut it so that you have two 1x8. Make sure that the side with the labels has the long ends of the posts, and the side you want to solder is the side with the heat sink. Doing this backwards will cause you not to see the labels and will most likely not fit. Remember to apply a heat-sink to the largest chip on the back.

Final Setup

Pre-Flight Check

If you think you may have mistakes you can install only one stepper driver during initial testing and risk only one stepper driver.

The trimpot on the stepper drivers controls the current limit. Turn it all the way down (counter clock wise) and back up 25%. Be careful to not force the trimpot, it is delicate. You will need to fine tune the current limit later. Note that it is allways giving the motors that much power, even when not moving, so if your stepper motor drivers are getting hot, you may want to turn it down slightly.

Connect the minimum endstops for X,Y, and Z

Connect Motors (Do not disconnect or connect motors while powered; if the connection is loose, this will cause the motors to spazz and possibly kill your stepper driver.)

You may want to use this code to test all the electronics before installing any of the suggested firmwares.

Install firmware (More info below). Firmware flashing can be done without 12V power supply connected.

Wiring

It is relatively simple to wire up the RAMPS. Just add the extruder heating coil wire to D10, the thermistor to the two T0 pins on middle right right, and wire up the steppers and endstops. From left to right, wire all of the stepper motor's wires as red, blue, green, and black or red, green, yellow, blue into the pins next to the Pololus. When you connect the wires to the endstops (if you are using 3 endstops, plug them into the MIN (-) slots), make sure you match the labels.

Note that tesla & tonok firmware use d9 and sprinter and johnny/tonok use d10 for the extruder hot end.

Warnings

Reversing +/- or otherwise incorrectly connecting power can destroy your electronics and cause fire hazard.

Incorrectly inserting stepper drivers will destroy your electronics and cause a fire risk. Always make sure power and USB is disconnected when removing or adjusting stepper drivers. Always make sure to insert drivers in correct orientation and in the socket correctly.

The endstop pins are Signal - GND - VCC, instead of the VCC - Sig - GND like the rest of RepRaps boards. Make sure to wire them correctly. This is done to allow squeezing fatter traces on the printable board.

Connecting Power

Connect your 12V power supply to the RAMPS shield. Reversing +/- or otherwise incorrectly connecting power can destroy your electronics and cause fire hazard.

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).

The barrel connector, on the Arduino MEGA, will NOT power RAMPS and will not provide power to the stepper motors, heated bed, etc.

The power connector plug may not be obviously labeled, looking at the power connection the positive is on the left and the negative is on the right of the plug.

Power Supply

[1] RAMPS is quite happy with the 12 V line from PCPowerSupply. Or you can hack up a 12V laptop power supply, or other 12 V "wall wart" power supply. Be sure that the power can output 5A or greater. Additional 11A may be needed for heated bed support. See Connecting power above. The 3 pins next to the reset switch are meant to optionally connect to your PSU. The PS_ON pin is intended to switch your power supply on and off. Many firmwares support pulling this pin low with M80 command to turn the power supply on, and M81 to turn it off. This behavior is desired for ATX power supplies and can be modified in firmware to support 5V high power supplies like those borrowed from an Xbox. Without D1 installed, or when the 12VIN is not connected, the Arduino gets its power from USB. If you want your kit powered without USB connected you need to solder in D1 OR connect VCC to your PSU. The VCC pin can be connected to your ATX's 5Vsb to continuously power the Arduino from your ATX power supply. You will want to make sure that D1 is not installed or cut out. The Arduino is not designed to be powered directly on the VCC rail and the VIN pin at the same time. The 5V pin in that connector on RAMPS only supplies the 5V to the auxiliary servo connectors. It is designed so that you can jumper it to the VCC pin and use the Arduino's power supply to supply 5V for extra servos if you are only powered from USB or 5V. Since there is not a lot of extra power from the Arduino's power supply you can connect it directly to your 5V power supply if you have one. You can also leave this pin not connected if you have no plan to add extra servos.

Assembly

Component Soldering

Required Tools

You must have: Solder iron, solder wire, good tweezers You really need: Solder wick, solder sucker, flux pen Optional methods use: Solder paste, hot plate or oven

Shield Assembly

File:RAMPS1-3pasteapplied.JPG

Soldering RAMPS 1.4 includes both surface mount and through hole soldering.

The surface mount can be done a few ways. Since all the SMT components on this board are large 2 pad parts you can do pin by pin soldering pretty easy with normal soldering equipment. Start by putting a small amount of solder on one pad. If you have flux, coat the soldered pad. Use the tweezers to hold the component down in position and heat the solder to tack the component into place (make sure the entire solder blob flows so you don't get a cold solder). Then solder the other pad. Also popular is using solder paste for pad by pad soldering, Oven Reflow (need link), and HotplateReflowTechnique

Solder the SMT components first. Then the PTH on top of the board. Finally solder the pin headers on the bottom.

C2 - 100nF capacitor

File:RAMPS1-3 100nF.JPG

This can be placed in any orientation.

LED1 - Green LED

File:RAMPS1-3 GrLED.JPG

Place these with the end having green dots away from the + mark on the PCB.

LED2, LED3, LED4 - Red LED

File:RAMPS1-3 redLEDs.JPG

Place these with the end having green dots away from the + mark on the PCB.