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Why MIN and MAX values in Datastream?

Why do we set MIN and MAX values in Datastream? What is the real purpose?
As is now:

  • It restricts data to be outside these values. (Is this really wanted?)
  • It controls widget range in displays (good!)

Example:
My outdoor temp sensors (datastreams) are typically set to -30 to 30C.
Now when hot, the temperature goes to 35C, but the gauges still display 30C.

  • Is this really wanted? To display an incorrect value?
    I’d say no. I don’t want to see a “false” temp value. Actually, I’d rater see “–” than 30 in this case. As 30 is incorrect.

Of course, I can define the temp range to -40 to +40. Sure I can.
But then, the temp goes to 41.2C, etc.

  • Whatever range we set, there is always a risk the measured values go outside our preset boundaries. And I prefer to see the actual value rather than my preset max.

I have an idea.
Would be good for me. Maybe not for others. Comments are welcomed.

  • Let a gauge display MIN and MAX as defined in Datastream.
  • DIsplay the ACTUAL measured value anyway in the gauge, even if outside the preset range (min,max).

See examples:

How it could look when displaying the ACTUAL value:
Skärmbild 2022-06-25 110524

How it looks now in Blynk when “limited to preset max” value is displayed.
Skärmbild 2022-06-25 110924

I prefer the first way of displaying the actual value.
I realize this could be argued with pros and cons.
Any thoughts?

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Currently server “crops” data that is outside of DS min/max.

Best way is to use your sensor datasheet and set up the min max accordingly to the limits.

I kinda like the idea of showing the actual value if it’s outside of the set range, but since it’s cropped at the server level, it’s currently impossible.

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I think the original idea of having min/max per DS comes from widgets. So in every blynk widget, we had a min/max settings, so the idea was to set up it up in one place and reuse it everywhere.

We can always fix the server. But I’m not sure this is necessary, as this is the point of min/max limitations, you’re not interested in values out of range (usually).

1 Like