Mounting Height in EVO is same regardless luminaire type

questions regarding the handling of DIALux evo. (features, tools, options, settings)
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Joined: Tue Oct 02, 2012 3:02 pm

Mounting Height in EVO is same regardless luminaire type

Post by kikeblackberry » Sun Jan 21, 2018 6:00 pm

For interior luminaires and regarding light centre height and mounting height of luminaires, it is clear that: The light centre height indicates where the photometry (= light center) is located related to workplane and The mounting height shows in which height the luminaire is installed.

For surface-mounted and Standing luminaires types, these values are very clear in EVO’s Luminaires Properties tab (for active luminaire). Although, for recessed and Pendant types it is not so clear because EVO still using the top height of luminaire as Mounting Height.

For a better understanding of mounting height, EVO should show bottom height of luminaire as mounting height when luminaire mounting type is recessed or Pendant because the reference plane is the ceiling itself (recessed) or an imaginary plane (pendant) parallel to ceiling. Mounting heights reporting by EVO in these cases are causing some confusion. For example, if ceiling level is 2.4m it is weird to find in report a recessed luminaire at 2.50m height.

According to Illuminating Engineering Society definition of mounting height, as you can see in this link, is: ... -interior/
mounting height, MH (interior)
[] The distance from a reference plane (e.g., floor or work plane) to a luminaire, or to the plane of the ceiling for recessed luminaires. The default reference plane is the work plane. The luminaire reference location should be stated (e.g., bottom or light center) to avoid ambiguities

Best regards,

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Joined: Mon Jul 06, 2015 2:16 pm

Re: Mounting Height in EVO is same regardless luminaire type

Post by F.Krewett » Thu Jan 25, 2018 3:23 pm

Hi kikeblackberry,

A discussion like this is always appreciated!

I think the differnt terms makes this confusion.
The Illuminating Engineering Society definition of mounting height seems pretty well to fit to the value which is called in DIALux "Light center height". For this value the height of the working plane is considered. Of course theoretically if the user is moving the luminaire outside a room the value can be higher than the room but practically it will not also for recessed luminaires.

The value in DIALux called "Mounting height" refers from the floor to the mounting point/origin of the luminiare. For ceiling mounted luminaires this point is usually on the top which explains why the values can be higher than the room. This value is another one as defined as "Mounting height" in the IES definition. But I must say the same wording is confusing.

As you will probably know the IES photometry file format has no information about the height of the luminiare case. You will also not find a defintion called "light center height" or for the value which we call in DIALux "Mounting height". In DIALux we support also other photometry file formats. Most technical terms are refering to the CIE definition.

From a logical perspective the names "Light center height" and "Mounting height" makes sense to me. Do you have an idea for better labels?

Best regards


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