Carel MCmultizone, User Manual

Page: 32 / 52

32
ENG
“MCmultizone” +030221981 - rel. 2.3 - 09.12.2014
cabinet
distribution
maint
enanc
e
10.2 Operating principle
The humidifi er controller - based on the input signal from a probe, an
ON/OFF contact or external controller - activates the cabinet to start the
production of atomised water (at maximum capacity), and stops the
production when the set point is reached.
As well as the room probe, the limit probe for humidity control is fi tted
in a signifi cant point of the installation to avoid excessive condensation.
Normally the humidity control probe is located in the ducts of the air
handling unit.
ON/OFF operation
The activation logic is:
Request ON (contact closed)
J
Humidifi er in production
No request OFF (contact open)
J
Humidifi er in stand by
(not in production)
Status of the outputs:
Humidifi er in production:
•
Water line active (NO drain solenoid valves active, NC fi ll solenoid valve
active)
•
Air line active (NC air line activation solenoid valve active)
Humidifi er off (not in production):
•
Water line inactive (NO drain solenoid valves deactivated, NC fi ll
solenoid valve deactivated)
•
Air line inactive (NC air line activation solenoid valve deactivated)
Operation in modulating versions
The humidifi er controller - based on the input signal from a temperature
or humidity probe, or external controller - activates and modulates the
quantity of compressed air so as to achieve a humidifi cation capacity
proportional to the request from the external controller, or to the
diff erence between the desired value (set point) and the value measured
by the probe.
In this case too, the limit probe is also used to measure the humidity in a
signifi cant point of the installation and avoid excessive condensation.
In
modulating operation, the system MANAGES a humidity set point ,
with an optional limit signal from the second probe, a temperature set
point or a request signal (proportional) .
Standard control of humidity production is performed using a
proportional valve
(AO2) controlled by a 0 to 10 V signal. The system
behaves as follows:
Status of the outputs:
Humidifi er in production:
•
Water line active (NO drain solenoid valves active, NC fi ll solenoid valve
active)
•
Air line active (NC air line activation solenoid valve active, Proportional
valve controlled proportionally to required pressure)
Humidifi cation not request:
•
Water line inactive (NO drain solenoid valves deactivated, NC fi ll
solenoid valve deactivated)
•
Air line inactive (NC air line activation solenoid valve deactivated,
proportional valve closed)
The use of the request signal and the extent of control of the proportional
air valve depends on the type of control selected.
ON/OFF and modulating control share the ratio between the values, that
is, the maximum signal applicable to the proportional solenoid valve
corresponds to the rated production (Pnom).
10.3 Control principles
ON/OFF control from contact
The action is all or nothing, activated by an external contact that
consequently determines the control set point and diff erential.
The external contact may be a humidistat, whose status determines the
operation of the humidifi er:
•
contact closed: the humidifi er produces atomised water if the remote
ON/OFF contact is also closed;
•
contact open: production ends.
ON/OFF control with humidity probe
The action is all or nothing, activated based on the reading of the probe,
production starts and reaches the maximum when the relative humidity
is lower than the set point by the set diff erential.
To set the set point and diff erential for the main control probe: SET
menu.
To check that the value measured by the probe is within certain preset
values, two alarm thresholds can be set:
•
high humidity alarm threshold;
•
low humidity alarm threshold.
When these thresholds are exceeded, an alarm is activated, after a set
delay.
Hy
Set point
%rH
Request
0
0
P. Max
100
ON/OFF control with temperature probe
The action is all or nothing, activated based on the reading of the probe,
production starts and reaches the maximum when the temperature is
lower than the set point by the diff erential.
To set the set point and diff erential for the main control probe: SET
menu.
To check that the value measured by the probe is within certain preset
values, two alarm thresholds can be set:
•
high temperature alarm threshold;
•
low temperature alarm threshold.
When these thresholds are exceeded, an alarm is activated, after a set
delay.
H
Set point
°C/°F
Request
0
0
P. Max
100