Talk:RAMPS 1.4

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In the Power Supply With/without diode sections, you mean D1 right? — Weasel 05:22, 4 December 2011 (UTC)

Contents

power terminal

The leads of the power terminal push against MEGA's power supply socket. You can't really fit the boards together

And did it really have to be SMT? -- Soleld 12:13, 13 March 2012 (UTC)

D1 D2 Diode

The information entered is confusing, please add a picture representing all three configurations I.E. D1 with D2 / NO D1 with D2 / D1 with no D2 / NO D1 with NO D@

(a better design for this should be made to prevent damage to electronics)

Wiring BlueTooth

I think there is a mistake in the picture : http://www.reprap.org/wiki/File:BT_Connection_RAMPS1.4.png The two resistor should be connected between GND and +5V and not with RxD.

would you like to add this link http://www.reprap.org/wiki/Jy-mcu to the bt discussion on page?

would you like to add this link http://www.reprap.org/wiki/Jy-mcu to the bt discussion on page?

http://www.reprap.org/wiki/Jy-mcu

it allows the arduino to directly setup the bt device in most cases.

The Picture of a fully loaded Ramps 1.4 is missing (not anymore)

The picture is missing of a Ramps 1.4 board with all of the stepper drivers fitted unless I missed seeing it..?

There are text warnings on the cct diagram about plugging the step-stick/Pololu drivers in the right way round but not one single picture showing "Them plugged in the right way round"

Here is a picture of a RAMPS 1.4 with a mix of driver boards:
Mixing A4988 and DRV8825 stepper drivers on the same RAMPS 1.4? Yes, you can!
More info in this page: A4988 vs DRV8825 Chinese Stepper Driver Boards
--AndrewBCN (talk) 18:37, 19 January 2015 (PST)

The jumper selector section is wrong

The jumper section for drivers is wrong - it can vary for drivers, like DRV8825. Section should mention this.

Small heatsink suggested for Q3 (heatbed MOSFET)

I strongly recommend using a small heatsink for Q3, the MOSFET used for the heatbed. This is because it carries heavy current when On i.e. up to 10A. From the STP55NF06 datasheet, we have the RDS-on (resistance of the junction when the transistor is On) = 0.015 Ohm. This gives us the power dissipation:

PD = I^2 * R or 10 * 10 * 0.015 = 1.5W

and we can calculate the temperature rise of the transistor using the thermal resistance of the TO-220 junction to ambient air again from the datasheet:

Rthj-amb = 62.5°C/W => temperature rise of junction = 1.5 * 62.5 => temperature rise above 90C

This leads us to the conclusion that the Q3 transistor without a heatsink will reach temperatures above 100C while the heatbed is heating up. With even a small heatsink, the transistor's temperature will remain in a safe zone below 65C.

In other words, it's a good idea to add a $0.10 heatsink to Q3 on the RAMPS 1.4 board for your RepRap.

--AndrewBCN (talk) 18:18, 19 January 2015 (PST)

Or use IRLB8743PBF instead, it's actually cheaper than STP55NF06L.--Manboy (talk) 17:28, 4 March 2017 (PST)

Back EMF, power voltage line

RAMPS design needs Back EMF shield for motor driver, like diodes. And also need seperate 35V input for step diriver.

The current design is faults when step motors has power drain.

Short circuit protection on stepper selection

A defective Pololu driver detonated the 5V regulator on my Arduino. A short between 5V and GND was discovered whenever the defective stepper driver had 5V and GND connected along with RESET, SLEEP, and MS3. Looking at the schematic, SLEEP and RESET are tied together via RAMPS, so my guess is that the MS3 (tied to 5V via step selection jumper) brought 5V into the defective chip, and a path to GND existed within the chip that required SLEEP and RESET to be shorted. Since we are only applying a logic level to the stepper driver, we should put a current limiting resistor in series with the step selection jumpers.

Short circuit protection on endstops

Current limiting resistors should be put between the 5V supply and the 5V pins of the the endstop headers. Many people are accidentally offsetting their connectors by one pin and shorting ground to 5V