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Novice Can't Figure Out Homing of Printer

Posted by eentwistle01 
Novice Can't Figure Out Homing of Printer
December 07, 2016 11:36AM

I am a computing novice and need to edit pronterface software. I have set up the printer and (using the SVG buttons on the Pronterface interface) I can make the printer nozzle more in whichever direction I choose.

My issue comes when trying to set the printers 'Home Position'. When i press the Home buttons the printer moves to its extreme in X,Y and Z directions. Is there a method to make the home position a different location on the printer?

From research I have seen that G92 X0 Y0 Z0 should tell the printer that it's current position is the home position, but this isn't working for me, so I'm assuming that's not right.

Any help you could give me would much appreciated!

Re: Novice Can't Figure Out Homing of Printer
December 07, 2016 02:43PM
Do you have EEPROM enabled? If so you need to save the changes with M500 otherwise it will keep using whatever is saved in the memory.
Re: Novice Can't Figure Out Homing of Printer
December 07, 2016 07:34PM
G92 X0 Y0 Z0 would tell the printer that the current position is X0 Y0 Z0

You could do this, then move X carriage say 20mm
You could return to X0 by issuing G0 X0 F1800 <that'd be 30mm/sec * 60 to achieve mm/min

But homing is different
It actually issues G28, it works in a way that it moves the direction it's told that the endstop (min or max) and expects to hit it, then stops. Counts that as 0

You'll need to do few things
Make sure that on the endstop switches themselves, you should have wires to the C and NC terminals
If your electronics have pins for Min and Max endstops, make sure they're connected to the Min

While looking at the printer from the front
X endstop should be at the Left
Y endstop should be at the Back
Z endstop should be at the bottom

Move the carriage and bed so none of the endstop switches are being triggered

Send M119
It'll tell you the status of the endstops
They should all read OPEN

If they read TRIGGERED
Test them by holding them down and sending M119

Whichever one you're holding down
If it doesn't change, you've got a wiring problem

If it switches to OPEN you have it wired up to the wrong terminal, double check that you have it connected to C and NC on the switch
If you do have it connected that way, it's inverted in firmware

You will go to your firmware and look for the following lines:
#define X_MIN_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
#define Y_MIN_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
#define Z_MIN_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.

For whichever Axis are working the opposite (Eg, TRIGGERED when switch is not pressed, OPEN when switch is pressed), change it to the opposite from what it is (Eg, false to true, etc)

Also in your firmware, make sure these are like this:
#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1

After you flash your firmware
Send M502
Then M500

(Shouldn't hurt even if you have eeprom off)

Then test
Place the carriage and bed in the middle of their travel
Also get ready to pull the power

Try one Axis at a time
Send G28 X0
It should move toward the endstop
If it does not, turn the power off and flip the X motor connector around

Test again the same way
It should now move toward the endstop
Press the endstop with your finger
It should stop

If not, something else is wrong

Do this same process for all your Axis
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