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How to

How to


Products: AS-B, Enterprise Central, Enterprise Server, AS-P, Virtual Project Servers
Functionalities: Trends
Product version: 3.2, 3.3, 2022
10/15/2020

Configuring Log Processing Trend Log

You configure a log processing trend log to enable calculation within or between various trend logs.

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A log processing trend log enables calculation within or between various trend logs. With this feature, building managers can gather new information about how the building is operating, they can view historical data that is calculated against new data and in this way detect new trends, they can compare various values and calculate a new trend log displaying relativised behavior, or unify measurements made with different units. The results from these calculations can indicate anomalies that have other reasons than the naturally varying conditions, so that it becomes easier to find problems with the building.

Examples

For instance, you use a log processing trend log in the following contexts:

Use a log processing trend log to compute the amount of the energy used during some given period of time, depending on the degree of the outdoor temperature. You can log this value along with, or instead of, the value of the outdoor temperature. You can also use some other energy measure such as degree days or an energy index listed in MSCI World Index. For this calculation you use the formula expressing the following function: “Energy consumption divided by energy index"

Use a log processing trend log to compute how much the light level differs from the natural light level. For this calculation you use the formula expressing the following function: "natural light level minus light level in the room".

Use a log processing trend log to store in a new log the average, or the minimum or the maximum temperature for a given period of time. You can log this value along with, or instead of, the value of the temperature. It can be further used by a 3rd party reporting tool. For this calculation you use one of the formulas expressing one of the following functions: "average(temp)" or "min(temp)" or again "max(temp)".

Use a log processing trend log to store in a new log the value of the total energy usage. You can log this value along with, or instead of, the values of the partial energy indicators. For this calculation you use the formula expressing the following function: "a sum of energy usage measured by multiple meters where there is no main meter".

Mathematical Operators Used in Calculations

The formulas for the calculations use operators discribed in the C++ Mathematical Expression Toolkit Library (ExprTk). For more information, see: https://github.com/ArashPartow/exprtk Scroll down to [SECTION 01 - CAPABILITIES] and [SECTION 02 - EXAMPLE EXPRESSIONS].

For instance, use:

(01) Basic operators: +, -, *, /, %, ^

(02) Assignment: :=, +=, -=, *=, /=, %=

(03) Equalities & Inequalities: =, ==, <>, !=, <, <=, >, >=

(04) Logic operators: and, mand, mor, nand, nor, not, or, shl, shr, xnor, xor, true, false

(05) @(My Trend Log:Count) will give you the number of records in the calculated period.

Non-Persisted Data

If data isn't persisted, calculation will be executed on the latest value while data is received. The latest value can change value until the period is finished. If data is persisted, calculation on the latest value will be executed first when the period is done. Views can then differ between a non-persisted log and a persisted log.

To configure log processing trend log

  1. In Workstation, in the System Tree pane select the folder where you want to create the log processing trend log.

  2. On the File menu, point to New, and then click Trend .

  3. In the object type list, select Log Processing Trend Log .

  4. In the Configure Log Processing Trend Log dialog box of the Create Object wizard, in the Name box, type the name of your log.

  5. In the Path , select the folder where you want to create the log processing trend log .

  6. In the Description box, type a description for the trend log.

  7. Click Next .

  8. Enter basic properties.

    Table: Log Processing Trend Log

    Component

    Description

    Start time

    Enter the starting date and time of the calculation.

    Period interval

    Type the time span of the calculation.

    Trend logs

    Displays trend logs that are used in the calculation.

     
    action_zoom_plus_stroke

    Click to add a trend log to be used in the calculation.

     
    action_zoom_plus_stroke

    Click to edit a trend log that is used in the calculation.

     
    action_zoom_plus_stroke

    Click to delete a trend log from the calculation.

    Name

    Displays the name of the trend log.

    Calculation type

    Displays the type of the calculation.

    Use last known value

    Displays the last known value of the calculation.

    Calculation value

    Type the formula for the calculation. For more information, see Log Processing Trend Log .

    Quick filter

    Displays the list of available log processing trend logs.

    Time zone

    Select the time zone for your calculations.

    Displaying timestamp

    Select the point in calculations where you want your timestamp to be inserted.

    Unit

    Enter the unit of your log.

    Last logged value

    Displays the last logged value.

    Last logged timestamp

    Displays the date and time of the last logged timestamp

    Fetch delay (min)

    Select the waiting time before the calculation starts.

    Persist data

    Select True to store data in the database.

  9. Click

     
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    to add trend logs to be used in your calculation.

  10. In the Choosing the Type and Naming the Object dialog box of the Create Object wizard, Name box, type the name of your trend log.

  11. In the Path box, select the folder where you want to create the log processing trend logs.

  12. In the Description box, type a description for the trend log.

  13. Click Next .

  14. Enter basic properties.

    Table: Configure Log Processing Trend Log Dialog Box

    Component

    Description

    Log reference

    Enter the unique identifier of your trend log.

    Name

    Type the name of your trend log.

    Calculation type

    Select the calculation type for your trend log.

    Use last known value

    Select True to use the last know value from the trend log.

    Log unit

    Enter the input unit of your log.

    Target unit

    Enter the output unit of your log.

    Log guid

    Displays the unique identifier of the log.

  15. Click Create .

  16. Select a trend log from the filter that you added and that are displayed in the Quick filter list.

  17. In the Calculation Value box, type the formula you want to use for creating a new value from your trend logs.

  18. Click Create .

See Also

  • Log Processing Trend Log
  • Create Object Wizard - Configure Log Processing Trend Log
  • Configure Log Processing Trend Log Item Dialog Box
  • Log Processing Trend Log - Basic Tab
  • Creating a Log Processing Trend Log
  • Creating a Log Processing Trend Log Item