Frequently Asked Questions

How Can I Tell if I am Overloading a Jace?
Last Updated 2 years ago

Subject: Jace Resource Monitoring
Manufacturer: Niagara
Model Range: AX-N4
Software Version: 3.1-3.8 & 4.0-Upwards

When using Workbench, right-click on the connected station in the nav sidebar and select View -> Resource Manager.

  • The CPU usage should be less than 80% on a continuous basis.
  • The heap.used should be less than 75% of the heap.max value. Execute garbage collection before evaluating the heap.max value by right-clicking on the connected station in the nav sidebar and selecting Spy -> util -> gc.
  • For a Soft JACE ensure that the is less than the licensed resource limit. Soft JACE's are licensed for either a 10,000 KRU or 30,000 KRU limit. If actual station resources exceed 110% of the licensed limit for a Soft JACE, the station will fail to start.

If running AX 3.1 or later, when using Workbench right-click on the connected station in the nav sidebar and select 'Spy'. On the Remote Spy page select 'platform diagnostics' and then 'fd usage'. This displays a list of processes and the number of open file descriptors for each.

QNX-based JACE controllers are limited to 1000 open file descriptors. File descriptors include but are not limited to directories, files, histories, and socket connections. If the number of open file descriptors exceeds the limit, the station will behave erratically such as misreporting available file space, missing history collections, etc. A maximum of 800 histories per station is recommended to avoid exhausting the pool of available file descriptors. Per issue 8943, in AX 3.2 and newer the maximum file descriptor count for JACE-4, 5, and 6 has been increased from 1000 to 2000. This allows customers to use up to 1600 histories in a JACE.

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