Siemens SIMATIC PN/BACnet LINK - Page 73

Configuring / Programming
9.5 Configure BACnet client
PN/BACnet LINK
Operating Instructions, 10/2017, A5E39895543-AA
73
Defining I/O object references
You can now configure references to their I/O objects for each BACnet device that is
created.
The configured references to I/O objects of the BACnet device are mapped as input and
output data in the corresponding process images on the PROFINET side.
1. To create a new I/O object reference, click the "New" button.
2. Select the type of I/O object. Possible options are: Binary input, binary output, analog
input, analog output.
3. Define the parameter values for the selected object type. Different parameters are
displayed depending on the selected type of the I/O object.
4. Specify the update cycle to access the "Present_Value" property of the referenced I/O
object.
Note
The specification of an update cycle is always required since
BACnet devices may exist
in the network that do not support COV (Change of Value). In this case, the value is
queried by the BACnet client function via polling. The query is made within the time set in
the update cycle.
If the cycle time is significantly
exceeded while reading an I/O object, the PN/BACnet
LINK sends diagnostics information to the S7 controller. The corresponding monitoring
time is the duration of an additional update cycle but at least 300
ms.
The smallest cycle time for your application d
epends, among other things, on the
following factors:
•
Number and type of the data to be transmitted
•
Reaction time of the addresses BACnet devices.