BACnet Buffer Full Broadcasts

Overview

• Trend logs only.
• The device that is writing to the log is saying that the log is ready to be read, and it hasn’t been read.
• Any traffic going into the log either doesn’t go in, or it overrides what was already there. This leads to gaps in data, either at the end of your data, or the front of your data.
• Traffic problems are causing BACnet Buffer Full problems, because the Buffer cannot be emptied. It cannot be emptied because it has not been read.

Why it fails

• The log is not being read.
• The archiver is not online, or somehow cannot reach the controller.
• The controller’s limits. Every embedded device has X amount of memory, so you can only put so much data on it.
• There might be traffic issues.
• It could be a configuration issue, if trend log source is too small. Maybe you’re collecting only five, instead of 2,000 entries. That would cause this notification to go off all the time.
• There should be a cleanup service. If there isn’t, the Buffer will continually fill up.

How to fix it

• Identify which device it was. Look to the source.
• Check the archiver.
• Check your configurations: how much data it’s storing, and how fast it’s filling up (in Visual BACnet, pps = how often it’s been sending out the notification on average).
• Check the router. If the router’s full or busy, it might not be able to read the log.