Siemens LOGO! CMK2000, Operating Instructions Manual

Page: 47 / 90

Configuring and commissioning using ETS
8.5 Parameter assignments for the KNX channels
CMK2000
Operating Instructions, 11/2015, A5E34877550B/001
47
8.5.4 Value update with data transfer from LOGO! to KNX
In order to optimize the bus load (message frame rate) on KNX, it is possible to activate
sending of values when they change. Each KNX channel can be parameterized such that a
KNX message frame is only sent upon certain changes in value. On the other hand, values
can also be sent cyclically in order to synchronize smaller changes in value which are not
time-critical.
Image 8-2 Value update on the KNX bus
Sending
For each channel you can define the cycle in which the value is to be sent to KNX. Criteria
for updating on the KNX bus can be a change in value on the one hand or the reaching of a
parameterized cycle time on the other. The following options are available for updating a
value:
Parameter Range of values
Cyclic Time value is parameterized
(Time unit: minute)
• 1…240
If value has changed Difference in values is parameterized
(Value without unit)
• 1 byte: 1...255
•
2 bytes: 1...65535
• 4 bytes: 1...4294967295
Cyclic and if value has
changed
Time value and difference in values
are parameterized.
The transfer is made as soon as a
criterion is satisfied. The cycle time is
restarted following the transfer of a
value.
The ranges apply as for cyclic / if
value has changed.
Note
•
Digital values are not affected by this parameterization of the value update. Digital values
are automatically transferred to the KNX bus upon each change in value.
•
A change in value can only be reliably detected if it is present for longer than the update
rate at which the values are read out from the LOGO! by the CMK2000.
•
The minimum change in value refers to the LOGO! range of values.