Replacing RAMPS 1.4 with MKS Gen 1.4

I have a Prusa i3 clone that has been working fine with the RAMPS 1.4/Arduino combination, with the exception of the heat bed which I cannot reliably heat over 60 degrees celcius. I have gotten a hold of an MKS Gen v1.4 board ..

[www.ebay.com.au]

My issue at the moment is that I can't find hardly any information on the wiring setup for this board. I have only found a Wiki page for the v1.1 version of this board which is slightly different (as per link below) which has different power inputs and outputs.

[reprap.org]

I am unsure where to plug in the sensor probe, end stops and heat bed.

"wah wah, my car is running slow, so lets replace the entire engine!!!"

Electronically both boards are almost identical, this will probably not solve your heated bed issues.



The thermistors are still not clear.. the are just to the left of the LCD connectors.

this helps



Edited 2 time(s). Last edit at 09/26/2017 10:28PM by Dust.

Thanks for the diagrams Dust, this clears almost everything up.

However I am confused about the Z motors / stepper drivers.

On the Ramps board, both Z1 & Z2 motors had separate connectors and only one stepper driver that controlled both, whereas this board appears to only have the one Z motor connector. Will I have to splice both the existing motor cables into one for this board?

Also, does it still only require the one stepper driver?

yes on ramp you have 2 steppers off of the 1 stepper driver.

You will have to wire them together. Ramps Z is wired in parallel, but there are some benefits to wiring in series

Left image is parallel, Right image is series



NB this image shows wiring for a push/pull system... where each stepper move the opposite direction to the other.
You need to match the stepper wire colors, black to black, blue to blue etc...


If you wish you can use E1 as second Z and use one stepper driver per stepper motor (its just a setting in marlin)
#define Z_DUAL_STEPPER_DRIVERS in Configuration_adv.h
This does need a stepper driver in the E1 position but it would mean you don't have to join stepper cables.

Edited 3 time(s). Last edit at 09/27/2017 03:23AM by Dust.

Thanks dust, that was exactly what I needed, and it all works fine. Much appreciated.

Well, I thought it was all working fine, however although the Z probe lights up when I touch metal to it, it is not triggering in the software (ie. when I send an M119 in Pronterface it stays open whether I have something metal against it or not).

I have plugged the Z probe into the Z- connector on the board (D18?). Is this the correct position?

It depends on what you have in your configuration.h

I ended up working out that I had the plug the wrong way around (the wires are not standard colours), so it's working now.

However as you alluded to in your first post, even with the new board, the heat bed is still not able to be heated to 110 degrees without a thermal runaway error.

So, would the problem be the heat bed?

most common issues with heated bed are:

no insulation under heated bed, so your just trying to heat up the room.
to weak a power supply. (check with a multi meter that you are getting the full 12v on the bed itself ) power supply should be at least 20amps
wiring to the heated bed to thin, so the wires heat up and not the bed. They shouldn't heat up at all.
if its a 12/24v bed, miss wiring the bed for 24v and applying 12v

If your power supply is adjustable, crank it up to 13 - 13,5v makes a huge difference in bed heating

If after all of those are correct, then it may be the bed itself

Edited 1 time(s). Last edit at 09/28/2017 06:03AM by Dust.

Problems with thermal runaway errors are caused by exceeding the BED_MAXTEMP setting in configuration.h. Find this line:
#define BED_MAXTEMP 125
It is around line 329 in the Marlin v1.1.5 "configuration.h" file, but it may be in a different place in the file in other versions. Set the value for around 7-10C higher than you ever expect to set your bed temperature, to allow for PID overshoot. If you try to set the bed above this temperature you will get a MAX TEMP EXCEEDED error. If you set it a bit lower but the BED_MAXTEMP is exeeded due to normal excursions of the bed temperature due to the PID loop overcompensating, then you will get a THERMAL RUNAWAY error. I never use my bed higher than 115C so I use 125 for BED_MAXTEMP. There is a similar setting for your hotend(s) called HEATERx_MAXTEMP where x is 0 through 4 to allow for multiple extruders.

Make the changes, save the file, then startup arduino and recompile, then upload to your board.

I have a problem. One motor is working faster than the other. What can cause it?

Quote
Dust
yes on ramp you have 2 steppers off of the 1 stepper driver.

You will have to wire them together. Ramps Z is wired in parallel, but there are some benefits to wiring in series

Left image is parallel, Right image is series

Steppers_Parallel_and_Series_2.png

NB this image shows wiring for a push/pull system... where each stepper move the opposite direction to the other.
You need to match the stepper wire colors, black to black, blue to blue etc...


If you wish you can use E1 as second Z and use one stepper driver per stepper motor (its just a setting in marlin)
#define Z_DUAL_STEPPER_DRIVERS in Configuration_adv.h
This does need a stepper driver in the E1 position but it would mean you don't have to join stepper cables.

I have a problem. One motor is working faster than the other. What can cause it? I used E1 as driver for second motor

Edited 1 time(s). Last edit at 04/08/2018 06:12PM by Doitmax.