First, second fiducial error

[jbasia]

Hurray, I am in the next level - vision!

First fiducial works good, but 2nd one gives me an error - must be ore than 2mm apart. 

Well, it's a cheap ruler and my not be 100% accurate, but I think it's a bit over 2mm:

How can I get around that?

[mark maker]

Read the error message more carefully.

And try to understand the reason why we need two fiducials in the first place.

https://github.com/openpnp/openpnp/wiki/Vision-Solutions#calibration-secondary-fiducial

_Mark

--
You received this message because you are subscribed to the Google Groups "OpenPnP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openpnp+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/c7dd8e38-e9f6-4c09-94bf-7f7dea017a09n%40googlegroups.com.

[jbasia]

Sorry, I don't understand. Primary and 2ndary fiducial must be more than 2mm apart. Left is prime and right is 2ndary. Distance apart (on Y)  is about 33mm. Or you mean X and Y 2mm apart? in Z they are about 5mm apart. But the nozzle can't go that low.

[mark maker]

Really? Read the f** message box!

And I sent you a link that explains this extensively:

https://github.com/openpnp/openpnp/wiki/Vision-Solutions#calibration-secondary-fiducial

Do you have some reading impairment I should be aware of?

_Mark

On 2/1/23 11:52, jbasia wrote:

Sorry, I don't understand. Primary and 2ndary fiducial must be more than 2mm apart. Left is prime and right is 2ndary. Distance apart (on Y)  is about 33mm. Or you mean X and Y 2mm apart?

On Wednesday, 1 February 2023 at 18:42:32 UTC+8 ma...@makr.zone wrote:

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/1facb0ce-8b89-43df-96ad-4945fc2f1dedn%40googlegroups.com.

[jbasia]

No need to get rude. I really want to get it to work. For the time I put in so far I could buy already two LumenPnP. I am really frustrated too. 

I move the nozzle to fidu 2, go as low as possible (fidu 1 can touch, fidu 2 not), and then I get that error. Fidu 2 is the right one in the image. Or need I place something else? 

Fidu 1 is for me at PCB level, Fidu 2 is 5mm lower, so can not touch.

I don't know where my error is.

[mark maker]

I'm sorry. There is a certain limit to my patience...

It is all explained in the Wiki. You need two fiducials at two heights.

https://github.com/openpnp/openpnp/wiki/Vision-Solutions#calibration-rig

The reasons for the two fiducials at different Z are explained in the link I sent you...

https://github.com/openpnp/openpnp/wiki/Vision-Solutions#calibration-secondary-fiducial

... and it says:

"...the Z coordinate is the most critical as any error there will result is a camera scaling (units per pixel) error"

And it goes on to explain how you need to touch the nozzle tip to get that precise Z:

https://github.com/openpnp/openpnp/wiki/Vision-Solutions#nozzle-offsets

Now you write:

> I move the nozzle to fidu 2, go as low as possible (fidu 1 can touch, fidu 2 not)

What do you think happens if you just ignore and simply skip the "most critical" coordinate?

This is a machine calibration, not a salad buffet!

Why don't you follow the recommendations of using a spare PCB and then mounting something on top for the second height, as shown in the Wiki rig (image above).

The recommendations have a lot of thought gone into them. If you use a PCB in your PCB holder, the primary fiducial is guaranteed to be at the correct PCB surface Z height, as it absolutely must. Plus every machine can obviously reach the PCB with the nozzle. Plus every machine can reach 2mm+ above the PCB. Plus when you're done calibrating, you can take the calibration PCB out of the PCB holder and store it.

Again it's all explained here:

https://github.com/openpnp/openpnp/wiki/Vision-Solutions#calibration-primary-fiducial

_Mark

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/d452b936-16e6-4fd4-b015-37b991eae663n%40googlegroups.com.