Manual Corrigo Ventilation, revision R
Chapter 5
Functional description
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5.4 Fan control
General
Fans can be 1-speed, 2-speed or variable speed via a frequency converter.
1-speed fans are controlled using the digital outputs "Start SAF-Normal" and "Start EAF-Normal".
2-speed fans are controlled using the digital outputs "Start SAF-Normal" and "Start EAF-Normal"
as well as "Start SAF-reduced" and "Start EAF-reduced" giving normal and reduced speed
respectively.
Variable speed control uses an analogue output per fan for controlling a frequency converter. There
are two setpoints for each fan, "Normal" and "Reduced". Pressure or air flow control can be used.
Variable speed fans can also be configured to be run with fixed output values.
Compensation curve
When running pressure control, it is also possible to temperature compensate the pressure.
Crosswise interlock
Crosswise interlock of fans can be configured, which e.g. means that if one fan stops, the other fan
will also stop.
Timer outputs, interlock at low outdoor temperatures
The fans are normally controlled by the timer channels for normal and reduced speed. At very low
outdoor temperatures, "2-speed fans" or "pressure controlled fans" can be forced to "reduced speed".
The limit temperature is settable and the function has a differential of 2K.
Normal, reduced speed
Units with 2-speed or pressure control fans are always started at "reduced speed". After a settable
time, Corrigo switches to "Normal speed" if normal speed is valid at start-up. When 2-speed fans
are switched from "Reduced speed" to "Normal speed", "Reduced speed" is first disengaged. About
2 sec later, "Normal speed" is activated.
When Corrigo switches from "Normal speed" to "Reduced speed", there is a settable retardation
time from disengagement to activation. See the section Retardation time.
The extract air fan and the supply air fan have individual start and stop delays which are normally
set so that the extract air fan is started before the supply air fan. If there are not enough digital
outputs for individual control, both fans will have to be started using the signal for the supply air
fan, and the delay be created using an external time relay.
5.4.1 Pressure control
Frequency control pressure
During pressure control, two separate analogue output signals are used for supply and extract air
and two separate analogue input signals for supply and extract air for pressure transmitters. The fan
speeds are controlled via frequency converters, thereby maintaining constant pressure. The pressure
transmitter inputs are scalable using “Min volt input (Vmin)” and “Max volt input (Vmax)”.
A digital activation signal is normally used for each fan ("Start SAF frequency converter" and "Start
EAF frequency converter"), for sending a start signal to the frequency converters. The start signal is
activated as long as the fan is expected to be running.
For the supply and extract air fans, there are two individually settable setpoint values, one
corresponding to normal speed and one corresponding to reduced speed. Changing between the two
setpoint values is done using the timer channels for normal and reduced speed or using digital input
signals ("Extended Operation, Normal" and "Extended Operation, Reduced").