Application

Room Segment Functions
Device Control Functions HVAC
69
Siemens Industry, Inc.
Application Note
A6V11692053
Smart Infrastructure – Building Products
2019-04-01
Note
This AF does not perform loop control; its main purpose is to execute commands.
Loop control processes (for this AF) are managed in the "room" AF(s) that
collaborate with this AF to command the end device.
Multiple radiator control: The radiator electric position collection object
(RadElPosCol) can reference and control multiple radiators.
Radiator electric position objects (RadElPos) are referenced by the radiator electric
position collection object (RadElPosCol); this collection object is a common node
for any / all RadElPos object(s). The value for RadElPos comes from RadElPosVal.
Downdraft compensation: The downdraft compensation feature slows the sinking
cold air flow at large window surfaces and combats cold wall effect at cold
perimeter surfaces. This feature activates the radiator when the outside air
temperature drops below a configured value, raising the minimum temperature of
the radiator to a value higher than it would be otherwise.
Valve Position
Outside Air Temperature
Y1DndftElPos: 100%
X1DndftTOa: 23°F
Y2DndftElPos: 25%
X2DndftTOa: 50°F
Downdraft compensation is implemented using a linear reset function. The
following graphic shows factory default values for X,Y downdraft compensation
parameters.
Parameter EnDndft must be set to 1:Yes for downdraft compensation to function
(see Configuration).
High temperature cut-out switch: This AF has a radiator over-temperature
detection input (RadOvrTDet) from a high temperature cut-out switch. The over-
temperature detection input object(s) are referenced by the radiator over-