PBF4 Pot has unwanted "curve" applied to it

Grid
1

Hello!

Just got a PBF4 and one of the pots seems to have a “curve” applied to it. When turning at a normal rate, it starts very slow then gets very fast towards the end (see video, i’m turning both pots at the sam rate).

Video: Screen Recording 2024-08-30 at 8.31.54 PM.mov - Google Drive

All the other pots are fine. I’ve deleted all action blocks from this curved pot and pasted the code from the other pots which turn normally, and it’s still the same. “Cleared” it too, same.

Any ideas what happened?

Thanks!

2

Can you go to a different page, default that entire page, then check the behaviour?

The one I could see that might impact that would besomething that pot element’s ‘Init’ tab.

self:potmeter_min() and self:potmetrr_max() could cause some unusual value scaling.

However, if you go to a different page, default the page, then test again, it should rule out a code issue.

3

Thanks! But how do I “default” an entire page?

1 Like
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Click on the ‘Clear’ button. Top right.

5

This could be a hardware issue, I asked @narayb to look into it!

6

Checking your video, it seems that a exponential pot got mixed with our linear ones during production (how does that even happen when we don’t stock those??), oops.

Send us an email to support@intech.studio and we’ll send you a new motherboard with previously confirmed linear pots!

Apologies for the inconvenience.

7

Thanks I have been emailing with Gergely simultaneously and let them know about your response here.

And I tried clearing the pages per _d4ydream’s suggestion which didn’t change anything.

I will be able to swap out the motherboard myself? I have a small screwdriver and some beginner electronics skills, but nothing much more advanced than that.

8

also having curves on the knobs i could definitely make use of one day, but why is it a hardware feature a not something that can be coded? (or it probably can be coded too?)

9

It would be possible to mitigate the exponential curve to linear in code, sure! Requires some custom code and a it should be linear again. Let me know if you’d want to try that, I’ll cook up the code and you could just apply it from Profile Cloud.

Swapping the motherboard only requires a screwdriver and 5 mins of your time. This article should show you the gist of the process.

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Sure the code would be a good fix in the meantime. Thanks!

11

Gotcha, I added it. You’ll find it in the Cloud, it’s called: “Exponential Pot Quickfix”. If the resolution of the pot suffers because of this, you could increase its resolution with the potmeter mode block and change the algorithm.

12

Thanks but that didn’t seem to change the behavior and it’s still an exponential curve. I found the preset, clicked on it, then clicked on the down arrow over the pot in question. I see the code block added on the int page and the LED color changed, so it seems to have loaded.

Really not a big deal as a new motherboard is being shipped to me, so don’t spin your gears on it too much! But let me know if I didn’t load it correctly or something, I’m new to Grid and Editor etc.

13

That’s really weird. The profile correctly sets the pot to logarithmic for me causing it to change values quickly at the start and slowly at the end of its rotation.

logpot

14

Oh sorry what initially meant was to have the exponential pot turned back to linear, not log.

15

Your exponential pot when scaled logarithmically should give you a linear potmeter. If you check the function I used in the configuration it’s even called explin, meaning it takes exponential values and should turn them into linear ones.

So it should be correct. In your video I can see the potmeter moving slowly at the start of its rotation and fast at the end. The config I sent you does the opposite, it starts fast and ends slow. In theory it should fix or at least mitigate the issue.