User Manual

Logical I/O blocks
Addressing the I/O blocks
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CM110664en_07 267 | 353
[PrVal] Addr1 Addr2 Addr3 Addr4 Comment /
Text group
1 0 0 0 0 Off
2 1 0 0 0 Stage 1
3 0 1 0 0 Stage 2
4 1 1 0 0 Stage 3
5 0 0 1 0 Stage 4
6 1 0 1 0 Stage 5
...
16 1 1 1 1 Stage 15
With binary mapping, more than one hardware input or output may be active.
BACnet addressing
Data can be exchanged via peer-to-peer communication.
The exchange takes place using the BACnet services defined in the BACnet
standard. The process employs mechanisms engineered in CFC which can be
tracked in online test mode, but which are based on BACnet objects and
BACnet services.
When engineering the exchange of data in CFC, it is important to take note of
the following:
● Addressing is via [IOAddr].
● Data is exchanged only between BACnet objects. The attributes of the I/O
blocks and pins must be defined appropriately, and the information must
also be made available in the form of a BACnet object. For this purpose, the
attributes of this block or I/O must be defined correctly.
● In BACnet terminology, the I/O block is a client which fetches the required
value from an object defined as the server. This process is carried out using
services defined by BACnet, e.g.: The client subscribes to the relevant
object (the server) using the SubscribeCOV service. The server then
supplies the value via the BACnet service COVReporting whenever it
changes by the programmed value, COVIncrement. ReadProperty (polling) is
another BACnet service. Here, the value is read at regular predefinable
intervals.
● Addressing is carried out via the Technical Designation (TD). Note,
however, that this Technical Designation must first be made known to the
client in the form of a reference address.
● The data is exchanged both within a given automation stations, and across
automation stations.
Addressing takes place via the input/output address [IOAddr] and always starts
with the prefix "B=".
The BACnet reference address is the same as the Technical Designation (TD)
of the value. The BACnet addressing syntax is as follows:
B=BACnetReference (BACnetConfig)
Example: B=Geb6'Lft3'FanSu'Mot'MntnSwi.PrVal(0)
The FB variable PollCyc is used instead of the prior BACnetConfig parameter in
the I/O address syntax, to distinguish between COV or polling:
FB variable IOAddr. FB variable PollCyc
BACnetConfig = 0 -> COV (Change of Value)
BACnetConfig = 1…65535 -> Polling in seconds
In an automation station operating as a BACnet device, the maximum number
of simultaneously supported COV subscriptions is limited to 400.
Peer-to-peer
communication
Engineering
Address syntax
Polling or COV
procedure