Issues creating content in Function Block Wiki

I have started putting text into the Function Block wiki under MaslowCNC/mechanics.

I am having trouble adding images. Since I cannot upload images to the Mechanics/Documentation folder I tried creating my own repository.

This allowed me to upload some of my images but I cannot reference them within the Wiki section.

Any help would be appreciated.



I think github ‘really wants’ to use links to images stored elsewhere for pictures in a wiki.
I think that to store them within the wiki structure will require going through the Pull Request procedure. Have you cloned the wiki (“”)? Once cloned, add a directory ‘Images’ - if it doesn’t already exist, and put your files in there. Create a PR to merge back to the master, and once it is merged you can use ![file placeholder text](Images/imagefile.jpg to link to them.
Anyone with more git-fu is encouraged to correct or simplify :smile:


@stuartri, I guessed at what you were trying to do in that wiki page and fixed the links so it points to the image I think you wanted.

The Wiki, as does the on GitHub, as well as the forums here, use a language called Markdown. Apologies if this is something you already knew but just in case, I’ve found the “Markdown Cheatsheet” very helpful.

The problem with the picture link you gave was that it wasn’t a valid link. GitHub likes to have the actual files references in their repos as:[USER]/[REPO]/raw/[BRANCH]/path/to/file

Though a little confusing, the idea is to give an actual link to the file, not the ‘pretty view’ of a file with all of the GitHub garnish around it. Compare the two links:

The first one shows the file as it sits in the repo, with all of the GitHub HTML “garnish” around it, including the GitHub header, links to whether you want to “watch”, “star” or “fork” the repo, relative paths of where in the repo it is, etc. The second link is a “raw” link to the file that serves the file plainly without any additional HTML around it.

Hope that helps.


Thank you so much for that abetusk. I would have been there all day trying to work this out as I am new to Github.

I will have a look at the code and work out where I went wrong based on your detailed response [brilliant]

The one good thing that came out of the frustration with Github is I am writing a Survival Guide in word to make things easier for new comers like myself and to ensure that I don’t loose data again each time I post as no doubt I will come across other issues.

These forums are a saviour

Kind Regards Stuart


Whoops, looks like I didn’t even read my own post. I guess there’s two ways to access contents directly:


It looks like both are valid in that they serve the raw file but the bottom one redirects to the top one. So I guess accessing files directly using is the preferred method.

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The Functional Block Diagrap page is looking good. If I could suggest a tweak, in the block ‘Motor-Gearbox-Encoder-Chain’, re-ordering them as ‘Motor-Encoder-Gearbox-Chain’ would reflect the present arrangement. It would make clear why the encoder sends so many pulses for each revolution of the gearbox output shaft,


That is ok abetusk. I just edited my post to look at the link format that worked.


Thanks for that Blurfl.

Just to clarify that I have this correct.

The encoder is measuring the motor shaft rotation and the gearbox is then coupled to the motor shaft. Under this arrangement the software calculates the speed of the chain by the actual motor shaft speed multiplied by the gearbox ratio (taking into account the teeth on the sprocket). Hence Motor-Encoder-Gearbox-Chain

Is this what you meant?

Kind Regards Stuart

That’s right.

And the link size of the chain.

Perfect thanks Blurfl. The image has been updated on the Function Block Diagram wiki area.

I am thinking of putting in a layer for the sled for completeness.

What I am thinking here is

  1. The Chains connect to the Sled via a mechanical mount. This will be left generic as currently there seems to be a couple of variants that impact quadrilateral or triangular kinematics (basic mount, Linkage kit, )

Chain / Mechanical Mount / Sled

  1. The router connects to the sled via mechanical mounts as does the Z Axis

This should leave us with a complete view of the system as is.

Your thought on this are very welcome.

Kind Regards Stuart

There are some system variables related to the sled, so it makes sense to capture all that in a sled block. What information will the router block capture?

I am open to all suggestions.
I will mock up what I was thinking and you can let me know if anything else is missing.

In terms of system variables these can be annotated links on the Block Diagram which is still in development.

Kind Regards Stuart

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and the system variables are vastly different for the two kinematics models,
they will need two different diagrams.

I would suggest using the simulator to show the types of errors that happen with
each variable being wrong (possibly one picture if the value is too large, and
another if it’s too small)

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I see these as specific links on the Diagram noting that the kinematics are actually different.

Please see the updated version of the Functional Block Diagram to indicate what I was thinking. I will indicate that the X & Y Axis motor assemblies are actually mounted to the frame but think this is an improvement and closer to the final diagram.

As always feedback is appreciated.

Kind Regards Stuart

I have added your suggested changes and am slowly progressing the Function Block Wiki. I have added in sections on the H-Bridge functionality concentrating on the Motor Shield at present.

Kind Regards Stuart

You might want review some of the 1’s and 0’s on those and gates… This page has a slightly different way of showing it.


Which ones were you referring to. I had to show the inverted state on the and gates, the ones with the circles even though the input is reverse. The output of the and gates should be correct.

If you can elaborate that will be great.


I finally clicked on the link so can now see what you are referring to. My logic is correct but I do like the colour coding. When I get the chance I will revisit. Great link.

Doing the PWM and quadrature encoding sections tomorrow.


There are the places I wondered about:

They are the only ones that don’t match the signal value at that point.

Thanks Blurfl, That was because of the inverted input but what I can do it put that logic in and for those confused by the inverted input signal an show the and logic.

I will also indicate that the 1 represents the logical high (ON) and Zero as a logic low (off).

Thanks Stuart

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