ABB i-bus KNX Product Manual page 51


ABB i-bus KNX
Commissioning
Monitor power values cyclically
Options:
•
yes: The 4 byte communication object Status load control is enabled. Using this communication ob-
ject, you monitor whether all enabled power values are received via the bus. The following parameter
appears:
Reaction time when exceeding load limit
in s [2...60]
Options:
If the sum of the power values exceeds the parameterized load limit, the master commences to send
shedding stages on the bus after the parameterized time. The shedding stage is increased until the load
falls below the load limit. The reaction time restarts before every further increase of the shedding stage.
Reaction time when falling
below load limit in s [30...65,565]
Options:
If the load is again below the load limit (sufficient slaves have been shed), the master waits for the pa-
rameterized time and then commences in inverse sequence to reduce the shedding stages until shedding
stage 0 is reached (i.e. all slaves are enabled) or the load limit is exceeded again.
Note
It is necessary to consider the reaction speed of the system. Depending on the number of shedding
stages and parameterized reaction times, it may take a long time before all slaves are re-enabled. If the
reaction times are too short and the system is frequently in an overload state (load limit exceeded), the
maximum number of relay switching operations (service life) can be reached prematurely.
Hysteresis for increasing load shedding
stage in % of load limit [0...100]
Options:
If the system is frequently at overload during operation, the hysteresis can prevent that a shedding stage is
continuously switched on and off. The hysteresis is subtracted from the load limit. Only when the limit val-
ue is less than the load limit minus the hysteresis will the shedding stage be reduced.
no
yes
Control period in s [20...65,535]
Options: 20...65,535
If the master does not receive all the external power values from the slaves within the parameter-
ized monitoring time, the missing values are requested via Value Read and an internal timer starts
(10 s). After the timer has timed out, the corresponding error bit in the communication object Status
load management is set and the value of the communication object is sent.
2...60
30...300...65,565
0...100
SE/S 3.16.1 | 2CDC 505 084 D0203 49