Applicatio Manual
Universal Interface 4 DIN/NTC EK- CG2-TP
Revisione 1.0.0 - Aggiornato: 04/09/2017
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MAEKCG2TP_EN
Pag. 23
The figure shows that, as long as the actual measured temperature is below the heating mode setpoint, the heating
mode is selected; similarly, if the value is greater than the cooling setpoint, then cooling mode is selected. If the
value is within the dead band, the operation mode remains unchanged; the heating/cooling switchover point must
correspond to the actual setpoint of the current HVAC mode, and in the same way the cooling/heating switchover
must correspond to the actual heating setpoint.
An automatic switchover can be performed by interlocking the valves based on the time needed by the actuator
to make a complete run. The switchover sequence includes the full closing of all intercept valves of, for example,
the hot fluid, before starting to open the valves of the cool fluid. This sequence can be realized with both
electrothermal actuators and zone valve drives.
7.7 Temperature control alarm
The integrated temperature controller can stop the internal control algorithm for one of the following reasons:
•
For an external event, which can be configured and linked to the
Thermal generator lock
communication object;
•
For an internal temperature sens
or’s fault (measured room temperature too low while NTC
resistance value is too high or vice versa);
•
For a timeout (data not updated by the bus) when a weighted mean between the internal sensor’s
value and an auxiliary external sensor’s value is used.
When one of these events occur, the internal controller stops the control algorithm and the command output is
taken to complete closing position (OFF or 0%): this state is indicated through the communication object
Temperature control alarm
.
8 Input from bus
8.1 Characteristics and timeout
When using the device with integrated temperature controllers, variables acquired from the bus are available,
which are different for each channel. All bus inputs allow to extend the device’s functionality..
