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Release status: Working

RAMPS eXpansion Board
CAD Models
External Link


RAMPSXB (RAMPS eXpansion Board) is a shield that attaches to the AUX pins of the common 3D printer control board, RAMPS.

It adds 4 additional stepper motor driver carriers, 4 additional thermistors, 4 additional PWM-controlled MOSFETs, EXP1 and EXP2 for an LCD controller (such as the RepRapDiscount Smart Controller), additional VCC pins, 5V pins, regulated TX/RX for an HC-05 chip, and suppression capacitors on the minimum endstops, similar to the RAMPS 1.4.2.

This allows for a variety of combinations, including 6 completely separate extruders, or a mixing extruder and a few fans, or a mixture of voltages (12V on the main RAMPS, and 24V on the RAMPSXB). It was originally designed to run either the E3D Kraken or Diamond Hotend, with some spare heaters for fans, lights or support extruders.

RAMPSXB consumes the maximum endstops, as well as servo pins 2, 3, and 4 to drive the FETs.

Reverse Polarity Warning

Generation3Electronics-achtung.gif Do NOT reverse polarity on the input pins, as there is NO PROTECTION DIODE. Reversing polarity will not only fry your steppers and FETs, but may even damage your Arduino and possibly even your computer. Triple check to make sure the polarity on your power input is 100% correct!

Overview Video

<videoflash type="youtube">VfZRG9I9bxY</videoflash>


RAMPSXB Schematic as of V2.3


RAMPSXB Layout as of V2.3

Open Source Files

EAGLE and gerber files can be found here: https://github.com/SZiv/RAMPSXB

Where to get it?

Reprap.me sells assembled RAMPSXB boards here: [1]

However, if you can manage to get ahold of the PCB board and components, its not very hard to assemble by hand.

RAMPSXB-TH (RAMPSXB-Through Hole), a fork

Must also comment on choice of Protected_Mosfets available when making Sinaptec, RAMPS and RAMPSXB. Basically this is a 2.5 layer or 3 layer board, i want it all to be through hole, as I am sick of buying new (hard to source) SMD components. This will be a fork. Spacewise how would the board look, is adequate spacing available for through hole components? 1/4W resistor, 3mm LED, through hole MOSFETs...
MOSFETs: yes, fork?
3mm LEDs: yes
capacitors: TBD, how can you standardize to 0805
resistors: yes

Response from SZiv:

There is not currently enough space to make everything through hole. The RAMPS side of the board can't really be touched without running into something on the RAMPS, but the other side can be knocked out and make the board longer. It will be more expensive a board to make, but the parts will be easier to source. I'll try and make an offical though hole version in the next few days because it sounds like an interesting challenge, or if you want you can fork the official repo and try it yourself. Any comments on the MOSFETs or do you think a through hole STP55NF06L would work?

Response from Jobo:

Protected_Mosfet: any type of N channel MOSFET will work depending on your Voltage and Current capacity/requirements.

100 uF capacitor, 4 pieces under motor driver chips, use same size as in SinapTec, had the same problem in SinapTec so make sure the size is correct.

Will through hole capacitors (8 X 14MM) fit into the circuit, is it necessary/possible to move the 4 10k resistors down in the design

Response from SZiv:

The capacitors that go under the drivers are filter capacitors that just connect VCC and Ground. Best I can figure out is that they are used to smooth out voltage spikes.

I ripped up all the traces and bumped the board out quite a bit to make everything fit, replaced all the resistors with 7mm 1/4W resistor slots and varying capacitor sizes I just pulled off of the capacitors of the same size I have lying around here, and heres what I've got:

Prototype RAMPSXB-TH Schematic


I'm not sure when I'll get a chance to run the traces, and I am waiting on verification that the circuit does indeed work before I tackle that. Once I get around to getting it done, I'll throw it up on github, or if anyone else gets a chance to finish it off, put it up and I'll throw it on the official github.

Any other ideas?

Response from Jobo

Not yet, many thanks for your work


Currently, Repetier is the only software that supports 6 extruders, as Marlin is limited to 5. A working version of the firmware is in the Github, and also here: File:RAMPSXB Firmware.zip

This firmware uses all 6 extruders and a Reprap Full Graphics Smart controller and heated bed. Unless you just so happen to have this setup, it is highly suggested that you go the the firmware configurator [[2]] and upload the Configuration.h file to adapt to your system needs.

If you are using your own version of Repetier, the important thing is to be sure to disable the maximum endstops (They are on by default and conflict with the stepper pins, so you need to disable them). Other than that, you'll need to go into Pins.h and set the E2-E5 stepper pins, heater, and thermistor pins by scrolling to "#ifdef RAMPS_V_1_3" and replacing whats there with this, assuming you intend to use all 4 heaters, steppers, and thermistors.

  #ifdef RAMPS_V_1_3
  #define ORIG_X_STEP_PIN         54
  #define ORIG_X_DIR_PIN          55
  #define ORIG_X_ENABLE_PIN       38 
  #define ORIG_X_MIN_PIN          3
  #define ORIG_X_MAX_PIN          2
  #define ORIG_Y_STEP_PIN         60
  #define ORIG_Y_DIR_PIN          61
  #define ORIG_Y_ENABLE_PIN       56
  #define ORIG_Y_MIN_PIN          14
  #define ORIG_Y_MAX_PIN          15
  #define ORIG_Z_STEP_PIN         46
  #define ORIG_Z_DIR_PIN          48
  #define ORIG_Z_ENABLE_PIN       62
  #define ORIG_Z_MIN_PIN          18
  #define ORIG_Z_MAX_PIN          19
  #define ORIG_E0_STEP_PIN         26
  #define ORIG_E0_DIR_PIN          28
  #define ORIG_E0_ENABLE_PIN       24
  #define ORIG_E1_STEP_PIN         36
  #define ORIG_E1_DIR_PIN          34
  #define ORIG_E1_ENABLE_PIN       30
  #define ORIG_E2_STEP_PIN         19
  #define ORIG_E2_DIR_PIN          15
  #define ORIG_E2_ENABLE_PIN       63
  #define ORIG_E3_STEP_PIN         39
  #define ORIG_E3_DIR_PIN          2
  #define ORIG_E3_ENABLE_PIN       58
  #define ORIG_E4_STEP_PIN         44
  #define ORIG_E4_DIR_PIN          42
  #define ORIG_E4_ENABLE_PIN       43
  #define ORIG_E5_STEP_PIN         47
  #define ORIG_E5_DIR_PIN          32
  #define ORIG_E5_ENABLE_PIN       57
  #define SDPOWER            -1
  #define SDSS               53
  #define ORIG_SDCARDDETECT       49
  #define LED_PIN            13
  #define ORIG_FAN_PIN            9
  #define ORIG_PS_ON_PIN          12
  #define HEATER_0_PIN       10
  #define HEATER_1_PIN       8
  #define HEATER_2_PIN       9
  #define HEATER_3_PIN       4
  #define HEATER_4_PIN       5
  #define HEATER_5_PIN       6
  #define HEATER_6_PIN       45
  #define TEMP_0_PIN         13   
  #define TEMP_1_PIN         14
  #define TEMP_2_PIN         15
  #define TEMP_3_PIN         11
  #define TEMP_4_PIN         12
  #define TEMP_5_PIN         10
  #define TEMP_6_PIN         5

Exposed Traces

The bottom of the RAMPSXB has a set of exposed traces.

Exposed Traces

These Traces are the main power traces that run to the MOSFETs. By default, these traces can easily carry 6A, and start to get warm at 9A. Since this is the sum of all the power inputs to the FETs, this is enough to run 3 40W 12V heaters at the same time (At 3A each). If you intend to run 4 heaters, your best option is to increase input voltage to 24V, and use 40W heaters (at 1.5A each), but if that isn't feasible, covering these traces with solder is another option. This increases the effective size of the trace without requiring 2 oz copper boards. Its a bit of a slow process and takes some soldering expertise, but it increases the max current (when it starts to get warm) to 12A, and can run just fine at 10A. This isn't suggested for beginners, but if you know what your doing it can give you that little bit extra power you may need.

Using a large sized and high powered (>30W) soldering iron, start at one end of the trace and slowly drag the iron along, tapping solder in behind it. I used a 50W iron with a knife tip, but anything that has a large surface area should work. If you've ever done stick welding, its a very similar process. If the edges look a bit sharp, its alright.

Slow and Steady...(But not too slow or you'll burn up the board!)

After covering everything in solder, run over everything again without the solder. This will smooth out some of the bumps, and give it a more even cover.

Whoo! Done!

And that's it! That wasn't so hard, was it? Make sure you double check you didn't short circuit anything, or jump any solder to the nearby vias. If you need more than 12A, you can theoretically add more solder, but each individual FET can only handle a few AMPs per trace, so try to keep it less than 5A per FET. Also, feel the temperature during your first few prints to be sure the board can handle the current, because continuous current and intermediate current behave differently. If it's too hot to touch after an hour, its probably a fire hazard.

Pin Definitions

E2 Direction - 15
E2 Step - 19
E2 Enable - 63
E3 Direction - 2
E3 Step - 39
E3 Enable - 58
E4 Direction - 42
E4 Step - 44
E4 Enable - 43
E5 Direction - 32
E5 Step - 47
E5 Enable - 57
Thermistor T3 - A11
Thermistor T4 - A12
Thermistor T5 - A10
Thermistor T6 - A5
MOSFET H6 - 45

Bill of Materials

Location Description Quantity Package Notes
C1,C2,C3,C4 Electrolytic Capacitors, 100uF, SMD 4 0605 For Stepper Carriers
C5,C6,C7,C8 Electrolytic Capacitors, 10uF, SMD 4 0405 For Thermistors
C9,C10,C11 Nonpolarized Capacitor, 0.47uF, SMD 3 0805 Suppression Caps for Endstops
R5,R6,R7,R8,R19,R20,R21,R22 Resistors, SMD, 100k Ohm 8 0805 For FETS and Pulldowns
R1,R2,R3,R4 Resistors, SMD, 10k Ohm 4 0805 Pullup Resistors
R15,R16,R17,R18 Resistors, SMD, 10 Ohm 4 0805 For FETs
R11,R12,R13,R14,R27 Resistors, SMD, 1.8k Ohm 5 0805 LED current limiting resistors
R23,R24,R25,R26 Resistors, SMD, 4.7k Ohm 4 0805 For Thermistors
R10 Resistor, SMD, 3.3k Ohm 1 0805 Half of a Voltage divider for the HC-05 Chip. No HC-05? You don't need this!
R9 Resistor, SMD, 2.2k Ohm 1 0805 Other Half of a Voltage divider for the HC-05 Chip. No HC-05? You don't need this!
Q1,Q2,Q3,Q4 MOSFET, PSMN7R0-30YLC, SMD 4 TO-220 Main Power MOSFETs. If using V2.1, use 3 stp55nf06l instead.
N/A TO-220 Heatsinks 4 TO-220 Heatsinks for the FETs. Not required, but dirt cheap and suggested if using through hole FETs.
LED1,LED2,LED3,LED4,LED5 LEDs, SMD 5 0805 LEDs that tell you if the FETs are on, and one that tells you if main power is on.
N/A Screw Terminals 5 3.5mm Input/output power terminals. If you need more than 4A, solder directly to the bottom traces.
F1 PTC Fuses 1 N/A 30V, 9A if you cover the bottom traces with solder for extra power, 6A if you don't.
N/A Male/Female Pin Headers A lot? ¯\_(ツ)_/¯ 0.1" spacing. Buy a couple of Female double rows, male double rows, male single rows, and female single rows.
N/A PCB 1 N/A The Actual PCB. I get mine from OSHPark, but you can get it from SEEED for better prices.