Manual Corrigo E Ventilation, revision M
Chapter 5
Functional description
42
Frequency control external control signal
Two 0…10 V input signals are used for direct control of frequency controlled fans. The signal is
received from for example a VAV unit. The signal controls the fans 0…100% (0…10V on the
analogue output). Pressure transmitters are not used in this control mode.
Frequency control SAF with EAF slave
The rotational speed of the supply air fan is controlled by a pressure transmitter which is placed in
the supply air duct. The extract air fan does not have a pressure transmitter, instead you let the
output for the extract air fan follow the control signal for the supply air fan. A scaling factor can be
added if the characteristics of the extract air fan are not the same as the characteristics of the supply
air fan. (Only pressure control of the supply air fan is possible using this function).
Frequency control SAF with flow control EAF
The rotational speed of the supply air fan is controlled by a pressure transmitter which is placed in
the supply air duct. The extract air fan is controlled by the supply air flow, in order to achieve a
balanced ventilation. A pressure transmitter which is placed in the supply air fan cone (Pressure
transmitter SAF 2) gives a measured value of the current supply air flow. A corresponding pressure
transmitter is placed in the extract air fan cone and gives a measured value of the extract air flow.
The extract air fan is controlled using the supply air flow as setpoint. A scaling factor can be added
if the characteristics of the extract air fan are not the same as the characteristics of the supply air
fan.
Minimum limit
For frequency controlled fans an adjustable minimum limit can be set individually on the supply air
and extract air fan control signals.
Inputs and outputs
1
-speed
2
-speed
Pres-
sure/
Flow
DO DO
Start SAF Normal
DO DO
Start EAF Normal
DO
Start SAF reduced
DO
Start EAF reduced
DO
SAF frequency start
DO
EAF frequency start
DI DI
Indication/alarm SAF
DI DI
Indication/alarm EAF
AI
Pressure transmitter SAF
AI
Pressure transmitter EAF
AI
Pressure transmitter 2 SAF
AO
Frequency converter SAF
AO
Frequency converter EAF
5.4.2 Demand controlled ventilation
In applications with varying occupancy the fan speeds or mixing dampers can be controlled by the
air quality as measured by a CO
2
/VOC-sensor.
