EVCO c-pro kilo AHU - Manual (Page 69)

C-PRO KILO AHU APPLICATION MANUAL
Pag. 69
6.11.5 Air quality control
The external air shutter may be used to replace the air upon request by the appropriate probe
(VOC/CO2). It is necessary to enable the parameter PS02=1, and the regulation probe for the
air quality (PH46>0). The external air shutter can be commanded based on the regulation
probe at set point (PS20) and at the relative differential (PS21).
Note. If the air quality probe is in error the regulation is inhibited. The probe can be one of
two types: 4..20mA (PH46=1) or 0..5V (PH46=2);
6.11.6 Shutter Command
The external air shutter can be utilized for two regulations: free-cooling/free-heating and air
quality control. The priority of these requests is decided by parameter PS03:
- PS03=0: The shutter is commanded by Free-cooling / Free-heating
- PS03=1: The shutter is commanded by air quality control
- PS03=2: The shutter is commanded by the largest request
- PS03=3: The request of the shutter is calculated as the arithmetic mean of the two
requests for free-cooling (/free-heating) and air quality control in order to fulfill both
active requests.
The shutters are managed through two digital outputs which are configurable by parameters
HS01 and HS02 which command the opening and closing, respectively. In order to correctly
command the external shutter motor it is necessary to set the following parameters:
- PS05. Minimum value of shutter opening.
- PS06. Maximum value of shutter opening.
- PS07. Shutter run time to go from 0% to 100%.
- PS08. Maximum time to maintain signal at end of relay.
- PS09 (optional). If greater than zero the command at relay are given only when the
actual variation on the regulation ramp exceeds the set value. If PS09=0 the
command will always pass.
Note. Each time the unit is in ON status (for turning on the card, for restoration of an alarm
block, or to restore the feed after a black-out), the external air shutters will re-align; for the
entire run time (plus eventual time PS09), the shutter will close and the regulation will be
interrupted. Once the run time has elapsed the regulation will return to its normal operating
state. This is necessary because there is no feedback for controlling the position of the
shutter.