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SD plus controller free time

Hi ALL

i am just trying to find out a way to figure out how much is left on SD plus controller free time 

DV is V11.3.1

thanks 

Y H

• 9 May 2023 1:12 PM
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5 Replies

• ElectroTech

  

  • 9 May 2023 5:08 PM

  There are a few ways to view controller free time. The simplest is to open diagnostics and click on the controller, it will be there under the listed parameters. You can also right click on the controller in diagnostics and get a more in depth view via the time utilization chart.
  If you are looking to trend this over time you can also build a controller monitoring module and an external reference parameter to controllername/fretim and add the tag to your historian.
  You should also be looking at idle time as well and make sure it is not dropping.
  Is there a particular issue you are troubleshooting?
  
  There are a lot of factors at play when looking to gauge controller loading. Controller redundancy and CHARMs are 2 that have a big factor on reommended freetime.

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• Former Member

  

  • 9 May 2023 6:23 PM

  unsubscribe

   

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• Andre Dicaire

  

  • 9 May 2023 9:35 PM

  In reply to ElectroTech:

  V 11 is a ways back. This original release of electronic marshalling introduced the SDPlus and SX controller. In this release, the controllers run the original Operating system and so have the FREETIM parameter, just like the M Series Controllers. In v12, the S series controllers moved to QNX OS and in v14, all M Series also moved to QNX. Diagnostics for Freetim are replaced by CPU % capacity.
  
  As ElectronTech mentions there is an option for TIME UTILIZATION CHART in diagnostics and this will trend IDLE, Control, Communication, Redundancy and Other tasks, that will all add up to 100% of the overall CPU resource of the controller.
  
  FREETIM is a function of the CONTROL task based on 65% of the total CPU. That is, if CONTROL task reaches 65% in the Time Utilisation CHARM, that equates to 0% freetime. When FREETIME is at 50%, control task would show 32.5% in the CHART.
  
  But wait, there's more. The minimum recommended FREETIM for an SDPLUS controller is 28%. That is, if you see FREETIME below 28%, your controller is considered Full. For M-series the minimum FREETIM is pegged at 20%. Why the difference? CHARMS adds a significant communications load to a controller as the IO comes in over the DeltaV Network, and not the separate IO bus for local IO. To make room for this, and ensure control modules are not starved for CPU, the minimum recommended FREETIM was moved to 28%. This moved 10% of the Control CPU over to Communications.
  
  If you monitor the IDLE time in the utilization CHART, and it is not 0, then you should be good. If IDLE time is 0% or hits 0%, the controller is overloaded and you might also see slippage. The other important measure is to look at the On Time Percent, especially for High priority modules. If all modules are "100% on time", then your controller is not overloaded. These are found in diagnostics under assigned Modules. If On time percent is significantly below 100, you are slipping and the controller is overloaded. You should adjust module scan rates or offload modules to restore a healthy Freetime with no module slippage. But if FREETIME has moved past 28%, this is technically not supported.
  
  Eventually, this system will hopefully be updated. The SDPLUS is supported up to v14, but will need to be replaced in v15 and later. The SQ controller is available and is compatible with v11 provided the required hotfix update was installed to support the SQ. This will give you about 15 5o 20 % capacity over the SDPLus.
  
  The FREETIM parameter can be trended, historized.

  Andre Dicaire

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• Y H

  

  • 10 May 2023 9:02 AM

  In reply to Andre Dicaire:

  Andre
  Thank you so much for your answer, Much appreciated, free processor time found 86

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• Y H

  

  • 10 May 2023 9:03 AM

  In reply to ElectroTech:

  Thank you so much for your answer, Much appreciated, free processor time found 86

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