DOL 278T
Technical Manual
5
1 Product description
DOL 278T is an advanced emergency opening unit providing optimum safety in connection with technical fail-
ures. This is achieved by means of a separate temperature sensor and manual setting of the temperature limit
for emergency opening. DOL 278T opens only as much as needed.
DOL 278T is specially designed for harsh livestock house environments. This applies to both climatic and elec-
trical influences. The system has a built-in 24 VDC motor power supply unit, maintenance-free battery and
charger.
DOL 278T regulates every three minutes. If the house temperature exceeds the setting of the temperature but-
ton by e.g. one degree, the shutters open only for a few seconds every three minutes. If the house temperature
exceeds the setting of the temperature button by e.g. six degrees, the shutters open for several seconds every
three minutes.
With it own outside temperature sensor DOL 278T takes high summer temperatures into consideration. Thus,
when the house is already open due to summer temperatures, the DOL 278T does not trigger an emergency
opening alarm.
DOL 278T and its settings are monitored by the house controller. It triggers an alarm, for example if DOL 278T´s
temperature button for emergency opening has been set too high or if the battery voltage is too low.
Emergency operation the first 3 minutes after supply voltage is restored
If the supply voltage is interrupted DOL 278T takes over the control system from the house controller and DOL
278T can open the shutters if necessary (emergency operation). When the supply voltage returns and the
house controller starts up again, there will be a risk heat loss during cold periods (outside temperature of less
than 20°C) when shutters are opened during start-up.
To lower this heat loss the DOL 278T controls the winch motors during the first 3 minutes after the supply volt-
age is restored, while the house controller starts up again. After this period the house controller resumes con-
trol.
On the other hand, during hot periods (outside temperature over 20°C) the DOL 278T makes sure that the cli-
mate control is restored as soon as possible by starting the fans as the house controller starts up.
DOL 278T in warm climates/Combi-Tunnel
When DOL 278T is used with a Combi-Tunnel house controller the jumper is to be set to
WARM
, so that un-
wanted emergency opening is avoided when the house controller runs in tunnel mode.
The following occurs when DOL 278T is set to
WARM
:
• Emergency opening is not triggered for high livestock house temperatures at outside temperatures over
20°C.
• Emergency opening is still triggered at power failure.
• At outside temperatures below 20°C the DOL 278T works as normal.
DOL 278T in normal climate
The following occurs when DOL 278T is set to
NORM
:
• Emergency opening is triggered even if the outside temperature is over 20°C.
• Emergency opening is still triggered at power failure.
At high power consumption
When a high power consumption exceeding 8 A is required, the DOL 278T can be extended with DOL 278 ON/
OFF of 4.2 A, 8 A or 10 A. See section
Setup options at high power consumption [
.
A mini UPS Mini Power unit is available as an accessory. This unit enables the house controller to regulate ven-
tilation for a short period during a power failure so that emergency control via the emergency opening unit does
not need to take over. The mini UPS module can be connected to an alarm system so that alarms will be gener-
ated when the module is active.
Содержание DOL 278T
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