Fan Coil General - ABB i-bus KNX Product Manual

4.5

Fan Coil general

© 2009 Busch-Jaeger Elektro GmbH – A Company of the ABB Group
Ventilator convectors, also referred to as blower convectors or fan coil units,
are used for decentralised heating and cooling. They are mounted in the
room and supplied by a central heating and cooling system. A distinction
is made between 2-pipe and 4-pipe systems (see also page 87, Section 4.3
Controller). A fan coil unit has multi-stage fans that enable fast adjustment
of room temperature as required by the user. The Fan Coil ambient
temperature controller with display can actuate up to three fan stages
manually or automatically.
The fan stagers can be actuated in three ways:
- with 1-bit values,
i.e. a separate 1-bit communication object "fan coil stage ... switch"
is available. This is required for "normal" switching actuators. (If KNX
switching actuators and fan coil units are used, note the connection
instructions of the fan coil unit.)
- with a 1-byte object as count value 0-3,
i.e. there is a 1-byte communication object "fan stage manual 1 byte",
which is linked to a corresponding communication object of a fan coil
actuator. Here the values are
0 = OFF
1 = stage 1
2 = stage 2
3 = stage 3
- with a 1-byte object as continuous value 0-100%,
i.e. there is a 1-byte communication object "fan stage manual 1 byte",
which is linked to a corresponding communication object of a fan coil
actuator. When a stage is manually switched, the stage fast values are
transmitted, which are set on the heating or cooling tab. In heating mode
the fast values for heating, in cooling mode the fast values for cooling.
The parameters of the fan coil actuator must be appropriately configured
to ensure that the fan coil unit also switches the fan stages.
The parameter "evaluate status byte fan stage" can be enabled by a 1-byte
communication object "state fan coil operating state", which is linked to a
corresponding object of a fan coil actuator. The fan coil ambient temperature
controller is able to evaluate which fan stage in the fan coil actuator is
actually enabled. The display shows the value of the communication object
(0 = OFF, 1 = stage 1, 2 = stage 2, 3 = stage 3).
The parameter "status byte evaluate operation" enables a 1-bit
communication object "receive in operation - actuator monitoring". Cyclic
telegrams can be received and evaluated at this object by the fan coil
actuator. This enables the ambient temperature controller to check that
the fan coil actuator is still operating and can be actuated. If the fan coil
actuator indicates a problem and cannot send cyclic telegrams, the ambient
temperature controller indicates this by showing the "fault" symbol in the
display. If the fault in the fan coil actuator is corrected and cyclic telegrams
are being received again, the "fault" in the display disappears and the
ambient temperature controller operates "normally" again.
When adjusting the cycle time "in operation" in the fan coil actuator, note
that it must be at least twice as large as the monitoring time in the ambient
temperature controller ("send cycle time of actuator in s"). A reasonable
cycle time for the actuator is approx. 60 s with a monitoring time of 120 s
in the ambient temperature controller.
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