Rev. d 01/1 36
DMP052E
EXAMPLE 2
:
OUTSIDE AIR PLANT WITH HEATING/COOLING ROOM TEMPERATURE TIME CONTROL
AND ON/OFF HUMIDIFICATION
A heating-cooling sequence with optional compensation, using the two analogue outputs having
(on request) limit action (anti-frost or max temperature) on any of the digital inputs, on/off
humidification.
Configuration mode facilities of two relays.
OPERATION
The PI controller carries out time control on room temperature (A2 sensor) or on air ejection (2B
sensor) by driving in sequence heating (4A) and cooling (4B) batteries valves with 1-5 and 6-9 Volt
range.
The room humidity (transmitter 3) is maintained at the set point by on/off control on the humidifier
(9). ModBus supervision is possible
.
Frost protection:
in case of heated fluid lack or faulty control, if the anti-frost thermostat (5)
detects a temperature lower than the set value, the controller stops the fan and closes the outside
air damper.
Obstructed filter
: the pressure switch (7) signals the presence of obstructed filter if the differential
pressure before and after the filter, increases over the set value.
Possible variants
:
Remote set-point of heating coil on SC input or outside compensated set-point with sensor on SC
input. The function “max humidity limit” is activated on the proportional valve (4) depending on 0-
100% signal given by SH input (Humidity transmitter), on set-point and humidity limit values set.
If the cooling request due to limit loop (dehumidification) is higher than that one for temperature,
the controller will give priority to the request of cooling (the loop limit signal is predominant), by
cooling more in order to condensate more humidity on supply.
It is possible to have a proportional humidifier where, instead of the Rel2 digital output connected
to on/off humidifier, the Ao2 analogue output is considered as connected to a proportional
humidifier.
In this case it is possible also humidification/de-humidification sequence by connecting in parallel
both the proportional humidifier and the cooling valve 4B to output Ao2.
