One end stop to pull them all...

Hi.

I have a problem with my end stops and my Sanguinololu.

I start all up, and no end stop is switched. I do a M119 in pronterface, which gives me:
"x_min:L, y_min:L, z_min:L"

When I touch one of the end stops (x, y or z), and do a M119 command in pronterface, it gives me back:
"x_min:H, y_min:H, z_min:H"

So all seems to be pulled at the same time. This makes it impossible to home my machine, what I wanted to do is to do:
x home
y home
z home

But I can only do x home, and the other axes move in the wrong direction as they believe they are already "home".

Has anyone encountered this and solved it? I have in my sprinter configuration tried both with and without commenting out the line:
#define ENDSTOPPULLUPS
but nothing works.

Thanks in advance

I think you have a hardware fault..

each endstop is connected to their own IO line... one cannot effect the others unless there is a short...

Oh, crap.

There is a contact between the signal pins on the board. Is this not normal?

I worked my way around this by each time starting a print manually zero the x and y axis, and then let the end stop only work on the z-axis. But in the end this is not what it should be like... So if someone has a bright idea I'm all for it.

no. there shouldn’t be any contact between the signal lines.

Its this a 40 pin dip SL? (big large black chip) or a surface mount job? (quite small, easy to short pins)

It's the big one (I believe).

See pics below.




There doesn't seem to be any connections between any of the pins on the backside. When I measure the resistance between two signal pins I get around 2 Ohm when the board is not connected to any power source.



I hope this explains.

Thanks for the support!

With the ATmega removed, the signal lines shouldn't be connected to anything, so infinite resistance between these three lines. 2 ohms might cause a distribution of one signal to all pins.

To remove the ATmega, carefully slide a small screwdriver underneath it.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

on your image for the bottom of the board just behind end stops is a thread connecting the endstop pins

check that thread isn’t conductive... remove it regardless...

Thanks.

When removing the ATMEGA there is infinite resistance between the signal pins on the connectors. So that seems ok.

I'm out of ideas, since a long time now...

I did as you say and removed any threads on the back and on the front of the card, but the result is the same. All end stops are pulled at the same time.

Can you measure wether actually all three pins go 5V? If not, it's time to check firmware configuration, like uploading something self-compiled, like using a known firmware instead fo the vendor supplied blob.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Alright.

I have loaded the Sprinter firmware from: [github.com]

How would I measure that? Between earth and the signal pin when I pull one of the end stops?

For example I pull the z end stop and check if the x, and y go to 5V?

Ok, so I did the following easurements:

with only z-end stop attached:
z-end stop not pulled
voltage between + and signal pin z-connector : 7.3 V
voltage between + and signal pin y-connector : 7.3 V
voltage between + and signal pin x-connector : 7.3 V

z-end stop pulled
voltage between + and signal pin z-connector : 12 V
voltage between + and signal pin y-connector : 7.3 V
voltage between + and signal pin x-connector : 7.3 V

with z- and y-end stops attached:
z-end stop not pulled, y-end stop not pulled
voltage between + and signal pin z-connector : 7.3 V
voltage between + and signal pin y-connector : 7.3 V
voltage between + and signal pin x-connector : 7.3 V

z-end stop pulled, y-end stop not pulled
voltage between + and signal pin z-connector : 12 V
voltage between + and signal pin y-connector : 12 V
voltage between + and signal pin x-connector : 7.3 V

z-end stop not pulled, y-end stop pulled
voltage between + and signal pin z-connector : 12 V
voltage between + and signal pin y-connector : 12 V
voltage between + and signal pin x-connector : 7.3 V

Does this make any sense?

Apparently you measure between 12V and signal. You should measure between signal and GND. Signal low means a maximum of 1.5V, signal high means at least 3V. Voltages should never exceed 5V.

Measuring pins not connected makes no sense. They pick up electromagnetic radiation and have arbitrary values.

Looking at the measurements (7V = 12V - 5V), your wiring apparently has indeed a short, so it's a wiring, not a firmware problem.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY