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Preliminary 003
Access V4.X Configuration manual
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2019-05-13
air fan output is made to follow the extract air fan control signal. A scaling factor can be added if the
supply air fan characteristics are not the same as the characteristics of the extract air fan (only pressure
control of the extract air fan is possible using this function).
Extract air fan pressure with supply air flow slave
The rotat
ional speed of the extract air fan is controlled by a pressure transmitter (”Pressure extract air”)
which is placed in the extract air duct. The supply air fan is controlled by the extract air duct flow to
achieve a balanced ventilation. A pressure transmi
tter (“Flow extract air”) placed in the extract air fan
cone provides a measurement of the current extract air flow. A corresponding pressure transmitter
(“Flow supply air”) is placed in the supply air fan cone, providing a measurement of the supply air fl
ow.
The supply air fan is controlled using the extract air flow as a setpoint. A scaling factor can be added if
the supply air fan does not have the same characteristics as the extract air fan.
Fan configuration
The controller supports number of Modbus communication capable fans. Such fans can be controlled
over internal bus of the unit. Alternatively, the fans can be hardwired to signal terminals of the
controller and controlled directly. Depending on preferred fan control type
–
several configuration
options are available.
Configuration: Configuration > Functions > Fan control >
The air handling unit can be a single flow (Supply air or Extract air) or two flow (Supply air + Extract air).
Flow presentation
Flow presentation is active if flow control type has been chosen. As an option representation can be
enabled to display flow of both fans even when pressure control or slave control is used.
If flow display is enabled by this option or by fan control type
–
right flow calculation settings should be
entered.
Configuration > Functions > Fan control > Flow calculation supply (extract) air >
k-
factor describes the characteristics of fan’s impeller. It is usually provided on the informational sticker
on the fan or in catalog data.
x-factor normally sh
ouldn’t be changed.
The following formulas for calculation of flow:
𝑭𝒍𝒐𝒘 = [𝑲 − 𝒇𝒂𝒄𝒕𝒐𝒓] ∗ [𝑷𝒓𝒆𝒔𝒔𝒖𝒓𝒆]
[𝑿−𝒇𝒂𝒄𝒕𝒐𝒓]
𝑰𝑭
𝑿 = 𝟎, 𝟓
𝑷𝒓𝒆𝒔𝒔𝒖𝒓𝒆
𝟎,𝟓
= √𝒑𝒓𝒆𝒔𝒔𝒖𝒓𝒆
Type of feedback Supply air fan (Extract air fan)
The controller supports simultaneous use of analog and digital fan operation watchdogs.