AIAS RC Techsheet IMO

20 / 26 | AIAS Room controller - installation and operation instruction
SPECIAL FUNCTIONS
Change-over function
Change-over is a function for installations with 2-pipe systems or
for pure VAV temperature control. It makes it possible to use the
same pipe for both heating and cooling, depending on require-
ments during for example the summer (cooling output) and the
winter (heating output).
Control modes
To activate the change-over function, control modes „Heating
or Cooling via change-over“, „Heating/Heating or Cooling via
change over“ or “Heating/cooling by VAV switched by change-
over“ needs to be congured.
The controller has an input for change-over. The input can be
either of the type analogue PT1000- sensor or a closing contact
connected to a digital input (FS=PT1000-input).
Change-over digital
When using a digital signal input (potential-free contact), closing
the contact will activate the change-over function and set the
heating output, UO1 alt. DO2/DO3, to cooling. On open contact,
the change-over function will set the heating output to heating.
Change-over analogue
In this mode, the change-over function will measure the diffe-
rence between the room and media temperature. As long as the
heat valve is more than 20 % open, or every time a valve exer-
cise is performed, the difference between the media and room
temperature will be calculated. If the temperature difference is
lower than the congured value (differs for Heating and Cooling
mode), the control mode will change. The factory settings for the
difference between Heating and Cooling change-over are:
• Change from Heating to Cooling = 4K
• Change from Cooling to Heating = 3K
This setting may be changed using parameters number 9 and 10.
Forced ventilation
The controller has functionality for forced ventilation. A digital
output for controlling a forcing damper to increase the airow
to the room. This output is always activated in operating mode
Bypass.
When control mode “Heating/Cooling with VAV-control and
forced supply air function” is active, the cooling output is used
to control the forcing damper. When forced ventilation is active,
the cooling output is set to full cooling, regardless of what the
controller output signal is.
It can be selected whether the forced ventilation output should
be a 0...10 V analogue output or a 24 V digital output (parameter
22).
Condensation detector
Special input CI
There is a special input (CI) on the controller. This input is inten-
ded for Regin’s condensation detector, KG-A/1, and functions in-
ternally as a digital input, i. e. condensation or no condensation.
When the condensation detector is activated, the cooling control
is blocked and the controller is set in neutral position. When
condensation ceases, the controller will start controlling from the
neutral position.
Window contact
When window contact has been congured, the controller is set
to normal mode on closed window. On open window, the cont-
roller is set to off mode, the heating and cooling outputs are set
to 0 V and the frost protection function is activated.
Frost protection
The controller has built-in frost protection, which is activated
when the controller is not in use. The frost protection prevents
the temperature from dropping below 8°C. Return to normal fan
speed and control occurs automatically when the room tempera-
ture exceeds 8°C.
High/low room temperature alarm
High/low temperature alarm is a function to indicate if the room
temperature is too high or too low.
The high room temperature alarm will trigger when the room
temperature exceeds the congured high temp limit (FS=40°C).
The low room temperature alarm will trigger when the room
temperature falls below the congured low temp limit (FS=15°C).
The alarms are implemented as points that trigger when the
temperature either exceeds or falls below the limits, and return
as soon as the temperature returns. There is no advanced alarm
handling, incorporating blocking or acknowledging or so forth.
There is only an indication for faulty temperatures. All other
alarm and alarm handling functions must be handled by a super-
visory system.