BACnet PTP Serial Driver Manual
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Appendix B. Troubleshooting
Appendix B.1. Debugging a BACnet Connection
•
If duplicate Object_Instances are configured in the FieldServer, the second call of the Instance will
overwrite the first one. This may cause a BACnet
Object to be “lost.”
•
If the Node Name configured on the BACnet Server Side of the configuration is not being indicated as
the Device Name on the BACnet SCADA system, then the FieldServer is not communicating with the
SCADA system. If the Device Object's name is being indicated, but the Present_Value shows
question marks, then it is likely that the Client side of the FieldServer is not communicating.
•
Extra memory is required to store Map Descriptors that have the active/inactive text parameters
specified. If the defaults are appropriate, do not specify these parameters. This will save memory and
allow more Map Descriptors to be created.
•
When a BACnet_PTP connection is established, and the connection is broken abruptly (for instance a
power down), the DEVICE might not know immediately that this happened. If the FieldServer is then
powered up again, it might take several seconds (up to 60 seconds) before polling will start again.
Appendix B.2. BACnet Error Response Decoding
BACnet reports errors in the following format:
T02> 10/22 02:57 HEXDUMP : ERROR_PDU
T02> 10/22 02:57 0x19d2d 50 97 0f 91 02 91 2a
T02> 10/22 02:57 BACnet -> Unexpected ERROR_PDU : err_class=2 err_code=42
These can be decoded using the following tables:
Appendix B.2.1. BACnet Error CLASS
Device
0
Object
1
Property
2
Resources 3
Security
4
Services
5
