limit switch blanks Rep Rap smart controller lcd screen

I am building 3 printers and it does it on all 3

Rep rap smart controller to MKS Gen l, v1.0 board. Limit switch ebay purchase, normally open, tested with multi meter and functional.

Board only connected to computer and smart controller, firmware flashed and details on lcd, all good

Plug in limit switch and screen goes black, unplug and it returns.

Have changed the endstop in firmware to both true and false no change.

Any endstop will make screen black

I have built another printer with the same components in the past and all good

What am I doing wrong? really stuck

That is a very good question Post. Are you sure that the End-stop Switches are connected to the correct two pins.

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Computer Programmer / Electronics Technician

Endstop plugs have 3 pins signal, gnd and 5v

Endstop switches should be between signal and gnd.

If the endstop is plugged in wrong, you short 5v to gnd and every thing stops.

I flipped the outer 2 wires and this resolved the LCD issue but now the printer doesnt see the endstops,

I can manually drive the z and y (direction X not working yet?) but when I trigger the limit switch on z and y nothing happens

Any suggestions?

Edited 1 time(s). Last edit at 04/06/2019 01:43AM by grunter.

get pronterface

run pronterface

connect to your printer in pronterface

Send the printer M119 command to view the current controller endstop status

view the status when the endstop is triggered and not triggered (trigger manually with a finger!)

If your endstops are just switches you need to enable the internal pull up in firmware

Your MOTHERBOARD must be set to BOARD_MKS_GEN_L for it to be looking at the correct IO pins.

G,day dust,

I am great at the mechanical but not so on the tech stuff.

Followed your instructions:

Did this and it says the end stops are triggered

Should I invert the setting in the firmware to be open, change to false. Sorry for the stupid questions, really out of my depth.

If they are reversed. Ie says open when it should say triggered or it says triggered when it should say open, but it does change from one to the other depending on if the switch is open or closed
Then yes invert the endstops.

If they don't change, its something else pullup resistors or motherboard settings, or plugged into the wrong endstop plug.

I will swap out the motherboard and lcd and start fresh with your instructions, to may issues.

thanks

Hi Dust,

all working perfect now, should have done that 4 hours ago, thanks for your help, I am always learning, now know about proterface. Your help with the limit switch got me on the right path Thanks for your time.

cheers
Grant