MINIMUM_LEVEL

[docsale]

Hi,

looking at this PID description, I was'nt able to fully understand how a responder should behave in response to MINIMUM_LEVE settings: if "On Below Minimum" = 1, what is dimmer supposed to do if DMX512 input is 0? It has to stay to minimum or turn off?

Thanks

Francesco

[ericthegeek]

Hopefully this graphic will help explain the behavior.
http://www.rdmprotocol.org/forums/attachment.php?attachmentid=42&stc=1&d=1396455699

Edit:
The forum software rescaled the image so it's a bit hard to read. Here's the text:

The graphic on the left:
One Below Minimum=1 A.K.A "Preheat"
Light output never goes below the minimum level.


The graphic on the right:
One Below Minimum=0
No light output until a minimum level is reached.
Typical behavior for dimmable fluorescents

[docsale]

Hopefully this graphic will help explain the behavior.
http://www.rdmprotocol.org/forums/attachment.php?attachmentid=42&stc=1&d=1396455699

Edit:
The forum software rescaled the image so it's a bit hard to read. Here's the text:

The graphic on the left:
One Below Minimum=1 A.K.A "Preheat"
Light output never goes below the minimum level.


The graphic on the right:
One Below Minimum=0
No light output until a minimum level is reached.
Typical behavior for dimmable fluorescents
Hi,

thanks for the support. So, in the "Preheat" configuration, output never goes OFF even if DMX512 is 0? To me it sounds quite strange but, if this is the standard requirement, i will follow it!!!

[ericthegeek]

thanks for the support. So, in the "Preheat" configuration, output never goes OFF even if DMX512 is 0? To me it sounds quite strange but, if this is the standard requirement, i will follow it!!!


Preheat is commonly used with incandescent lamps. By keeping the filament glowing at a very low level you can get much faster response when you want a fast turn-on. It's a major energy waster so not used as often as it was in the past, but still a useful feature. In shows with lots of flashing, it can also improve lamp life.


There's no requirement that you offer a preheat function. If your product supports preheat, you can use this PID to control and report it, but if you don't want to offer this feature, you don't have to. It's entirely your choice. It depends on the kind of product you are building, and the needs of your customers.

[este_]

Mostly, MINIMUM_LEVEL will go together with MAXIMUM_LEVEL. When setting both, the usable fader travel will be narrowed (between the yellow dotted lines).

43

There is a simple way to widen the fader range. Simply calculate OUTLEVEL = INLEVEL*(MAX_LEVEL-MIN_LEVEL) + MIN_LEVEL and you can make use of the full fader range. We have added a parameter (flag) to do so and this would be a nice complement for the "ON_BELOW_ZERO" Flag. Maybe this option could be added to the MIN_LEVEL PID in future versions.

[zano_villa]

Hello,

here's a question about Split levels in Minimum level PID.
If I correctly understand about Increasing and Decreasing definitions, I infer that Increasing minimum Level has to be set higher than Decreasing one.....
Is my interpretation correct?
If not, could you explain better this topic?
Thank you

[ericthegeek]

From the protocol perspective, it doesn't matter. You can put any value in either field.

But in most cases those fields are used to provide hysteresis for applications and lamp types that need it. In those cases, yes, you'd expect the "increasing" value to be greater than than the "decreasing" value.

[zano_villa]

Mostly, MINIMUM_LEVEL will go together with MAXIMUM_LEVEL. When setting both, the usable fader travel will be narrowed (between the yellow dotted lines).

43

There is a simple way to widen the fader range. Simply calculate OUTLEVEL = INLEVEL*(MAX_LEVEL-MIN_LEVEL) + MIN_LEVEL and you can make use of the full fader range. We have added a parameter (flag) to do so and this would be a nice complement for the "ON_BELOW_ZERO" Flag. Maybe this option could be added to the MIN_LEVEL PID in future versions.


(INLEVEL*(MAX_LEVEL-MIN_LEVEL))/MAX_DMX_LEVEL + MIN_LEVEL

[ericthegeek]

There's not one "correct" equation. Dimmer curves (the DMX to output level mapping) is the subject of endless debate. este_'s equation might work for some users. But, if the user wants levels to match between fixtures with and without preheat, then it's not the best choice.

From the standard's perspective, any output mapping is acceptable. You can also expose multiple dimmer curves via RDM to give flexibility.