User Manual

BACnet/IP networks
Diagnostics and troubleshooting BACnet/IP networks
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4.4 Diagnostics and troubleshooting BACnet/IP networks
General procedure for diagnostics and troubleshooting
BACnet on IP involves the use of a large number of components and this results in a certain degree of
complexity and a corresponding vulnerability to errors.
If a problem arises in the system, it must be located in a step-by-step procedure. Always start you analysis
at the lowest system. Only continue to the next higher system once you are sure that the system is
operating correctly. A sketch of the topology is extremely helpful when attempting to locate problems.
Create a sketch if none exists.
The following questions can help to troubleshoot communication problems.
Faults Possible causes & troubleshooting
Is the link signal available on the IP
components?
With switches, the link signal is indicated by a
continuous or flashing LED. In all devices in the
Desigo system, the Service LED is continuously
ON if no link signal is detected.
● Is the extension module (PXC modular) plugged in firmly?
● Are all connectors firmly in their sockets?
● Is there supply voltage for the switches?
● Were the RX and TX connections mixed up on fiber optics?
● Is the setting for the switch/router port correct?
Are VLAN switches used on the network? ● Are all BACnet devices configured on the same VLAN?
● A number of managed switches offer information on their own web interface
on connected devices. This includes, for example, port speed, VLAN
association, and packet statistics. The latter can also provide references on
insufficient cabling.
Diagnostics via wireshark is not possible. No port mirroring configured on the managed switches
● Use of hub or configured switch
● Consultation with customer IT on the use of wireshark
Wireshark does not have the proper BACnet
services.
Layer 2 switch is used, but without port mirroring
Use a hub or configure a corresponding layer 2 switch via the web interface
No communication between the BACnet client
and the various BACnet devices.
Is a firewall available?
Consultation with IT, cannot be discovered using the diagnostics tool.
Firewall, UDP port configuration is not entered
The BACnet clients cannot access the different
BACnet devices on the various VLANs.
BBMD in multiple IP segments
BACnet devices do not have a unique instance number
BACnet devices do not have a fixed IP address (if configured as BBMD)
BBMD used, but all BACnet networks are the same UDP port?
Have you considered notes from technical
documentation?
●
Desigo Ethernet, TCP/IP, MS/TP and BACnet fundamentals (CM110666)
Communication, speed on the Desigo network Compliance with system topology, regarding:
● Number of devices on a BACnet network.
● Max. number of 500 commanded group members. No more than 500
addresses can be managed.
● Max. number of 250 group members. The interface performance when
acquiring data is limited, in other words, only a limited number of telegrams
can be processes in brief period.