Functional Analysis Of The Control - CIAT AirControl CTA Manuel De Régulation

1.5 Functional analysis of the control:1.

1.5.1 Management of on and off modes
Powered up
OR critical fault
Off
request
Starting up and switching off will take place locally by pressing on the  and  keys on the display.
Remote control is available and carried out by a potential-free contact between terminals 1 and 2 in place of the factory-installed
shunt.
The unit is to be switched on/off by the CMS.
The unit will start up if the 3 running orders are actuated (on the display, on the remote control and via the CMS, depending on
the configuration).
If one of the 3 orders is in "Off" mode, the unit will be stopped.
1.5.2 Safety and isolation damper
The insulating damper is activated by an On/Off servomotor with spring-return.
When the unit is stopped, this damper is normally closed.
When unit start-up is requested, it will open then send the information used to open it back to the PLC (via an end of travel
contact); the unit will then be switched to "on" mode and the damper will be kept open until the next unit stop request or, if
operating with a safety damper, when the Frost protection alarm appears.
1.5.3 Frost protection thermostat
The frost protection thermostat has a manual reset and it is constantly monitored once the controller is switched on.
If an frost protection alarm is activated, the fresh air damper is closed, the valves on the hot water coil installed in the air handling
unit are opened fully and the fault is signalled.
A frost prevention function is available once the unit is switched off. This consists of leaving the hot water coil valves slightly open
(adjustable value) to maintain pre-heating.
1.5.4 Fire fault
The optional fire fault contact triggers a close contact relay.
- One contact wired to an input on the controller so that the latter can signal the occurrence of a fire fault.
- A second contact connected to the terminals to feed back information.
- A third contact in series with the control for relays KV1 and KV2 authorising fan operation
The other faults are described in the alarms table.
Unit off
On request
AND on authorisation
AND NO critical fault
Unit powered up
Air flow rate OK
Unit on
Off request
At least 1 override requested
Manual mode
No override requested
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