Function Time - ABB i-bus KNX Product Manual

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ABB i-bus KNX
Planning and application
Function of the load control
The number of shedding stages that the master can send is determined in accordance with the number of
priority stages that should be switched with the slaves. If the system only has two priority stages available,
for example (priority 1 = always on; priority 2 can be switched off if required), one shedding stage is suffi-
cient.
A Load limit can be parameterized on the master that cannot be exceeded. Alternatively, a load limit is
available that can be changed via the bus, or there are four load limits available that can be alternately ac-
tively switched via a communication object.
Up to ten communication objects can be enabled that receive power values. The Power values 1...4 can
also be internally logically linked, i.e. the Active power Output A...C or the Active power total of the master.
The received power values of the slave should generally be sent after a change. As soon as the master
receives a new Power value, the sum of the power values is recalculated and a shedding stage is sent on
the bus if necessary. Additionally, a cyclic monitoring time can be set. If the power values are not received
within this monitoring period, the missing value is requested. If the value has still not been received, the
corresponding bit in the diagnostic byte Status load control is set.
Depending on how fast the system should react, the reaction time is selected for when the load limit is ex-
ceeded and for when it is under the limit. If the value falls below the load limit, after the Reaction time
when exceeding load limit has been completed, shedding stage 1 is sent on the bus. If the load limit is still
exceeded, after a renewed Reaction time when exceeding load limit has been performed, the next shed-
ding stage is sent until the value is again below the load limit. After the Reaction time when a value falls
below a load limit has been completed, the master reduces the shedding stage (restart attempt).
The service life of the relay must be considered with the parameterization of the reaction times. The sys-
tem must be designed to ensure that the Load control is only active at peak times or the reaction times for
exceeding or falling below the load limit must be selected to be correspondingly long, so that frequent
switching is avoided.
4.1.5

Function Time

The function Time can be enabled (value 0) and disabled (value 1) via the bus (1 bit communication object
Disable function time). The output operates without a delay as long as the function Time is disabled. Diffe-
rent functions can be realised using the function Time:
•
Staircase lighting
•
Switching ON and OFF delay
•
Flashing
128 2CDC 505 084 D0203 | SE/S 3.16.1