Data Exchange Between Pn/Bacnet Link And Other Bacnet Devices; Data Transfer As Client - Siemens SIMATIC PN/BACnet LINK Operating Instructions Manual

Functions

4.4 Data exchange between PN/BACnet LINK and other BACnet devices

Effect of the S7 communication state on the status information of server objects
For server objects, the S7 controller can only affect the OUT_OF_SERVICE status flag. The
other status flags are set completely by the PN/BACnet LINK. The state of the
OUT_OF_SERVICE status flag which is specified by the S7 controller can be overwritten by
internal states of the PN/BACnet LINK.
State of S7 communication
S7-CPU in RUN mode
S7-CPU in STOP mode
Error in PROFINET communica-
tion
4.4 Data exchange between PN/BACnet LINK and other BACnet
devices
4.4.1

Data transfer as client

Transmission types
Possible transmission types:
● Transmission on change
● Cyclic transfer
Writing values
For values that are written from the S7 controller to BACnet objects, the user can configure
in the HSP whether this write operation is only to be performed in the event of a change of
value or cyclically. With cyclic sending, the user can assign parameters for the cycle times.
The cycles start with each activation of the client function by the client control bit. The data is
transmitted for the first time at the start of a cycle.
For write operations, the user can set priorities from 1 (highest) to 16 (lowest). The set
priority applies globally to all devices and is used for the corresponding "WriteProperty" call.
With the transmission mode "Send if value has changed", the user can specify for each
analog value how big a change of value is required to trigger transmission. If "0.0" is
specified as the value change, the corresponding analog value is transmitted in the shortest
possible cycle.
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Status information of objects
The OUT_OF_SERVICE bit is set in the "Status_Flags "Property
in all objects based on the S7 status information.
The "Out_Of_Service" property represents the" Out_Of_Service"
bit from the "Status_Flags". When the bit is updated, the property
is also updated accordingly.
"Out_Of_Service" property of all objects is set to TRUE (1).
Operating Instructions, 10/2017, A5E39895543-AA
PN/BACnet LINK