Siemens SIMATIC PN/BACnet LINK - Monitoring Functions

Functions
4.6 Monitoring functions
PN/BACnet LINK
42 Operating Instructions, 10/2017, A5E39895543-AA
4.6
Monitoring functions
Diagnostics with activated device monitoring
For monitoring of configured BACnet devices, the PN/BACnet LINK cyclically requests the
property "System_Status" of the devices in question.
The cycle time with which the PN/BACnet LINK reads out the property "System_Status" from
other devices can be configured. The configured cycle time applies globally for all devices.
If data is to be written to a device, then all "System_Status" values not equal to
OPERATIONAL are classified as an error state.
If data is only to be read from a device, then all the values not equal to
OPERATIONAL_READ_ONLY and OPERATIONAL are interpreted as error states.
The PN/BACnet LINK sends diagnostics information to the S7 controller in the following
cases:
● An error condition is detected in a configured device.
● The device does not respond to the reading out of the "System_Status" properties.
Note
W
ith activated monitoring, the set monitoring time may act as a delay when a failed device
starts working again.
Diagnostics with deactivated device monitoring
When the monitoring of configured BACnet devices is deactivated for the BACnet client, the
failure of BACnet devices is still recognized in the following cases and signaled to the S7
controller by means of diagnostics:
● Output references are configured for the BACnet device (references are written cyclically)
● Input references are configured for the BACnet device without COV (references are read
cyclically)
This means device monitoring is only necessary when clients exclusively have COV input
references.
Use of acyclic services for diagnostic messages
The S7 user can access any property of BACnet objects with "Read data record". This
allows the S7 user to read additional information from the affected device if needed.