Data Sources - Flow Historian Simulator Customization

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The Flow Historian Simulator is configured using an XML "Defintion" file. You will find the default "Juice Factory" file in your “C:\ProgramData\Flow Software\Flow\Config\Simulator” folder.  If you would like to create your own simulator files, we recommend you create a copy of the default "Simulator.xml" file and modify it little by little until you are comfortable with how it works.

The following is a section of the default "Simulator.xml" file.



Notice how the XML structure is made up of a number of nested <folder> elements.  These elements are used to create your Namespace folder structure.  The <folder> element only requires a "name" attribute.


Within the folder structure, you can add <item> elements.  <item> elements represent the definition of a tag, including instructions on how to generate historical data for it.

Each <item> has the following attributes to define typical tag properties:





Name of the tag



Description of the tag

"Boiler Pressure"


Unit of measure



Data type of tag value

integer / double


Item data is generated, but tag is not displayed in Namespace

false / true


Reference to another item by Name. Typically used to align tag generation to a "state" or "step" item.


Each <item> must contain at least one of the following elements to define its data generation:

  • one or more <step> elements
  • one <integrator> element

A <step> element is used to generate a value for a tag for a specified duration.  Where multiple <step> elements are defined, the simulator will cycle through them and loop back to the first <step> element as long as required.  Each <step> element has the following attributes to define its data generation:





Value of the step. This can be a specific value or a randomly generated value.


"random(95, 105)"


Duration of the step, specified in day.hour:minute:second



Minimum duration of the step.  Used with durationMax. Simulator will select a random duration between durationMin and durationMax.



Maximum duration of the step. Used with durationMin. Simulator will select a random duration between durationMin and durationMax.


Reference ???

An <integrator> element is used to generate a ???



When the simulator is first used, it will generate data for all the items configured as a once-off operation.

By default the simulator will generate data from the beginning of the 1st day of the month 3 months ago (e.g. if we are in June, simulated data will begin on March 1st).  This allows for the demonstration of Flow's backfill functionality.  This historical duration can be configured by changing the "duration" attribute of the <simulator> element (line 2).

The simulator will always generate data up to the end of the month following the current month (e.g. if we are in June, simulated data will end on August 1st).

Adding Custom Definition

Once you have built your “Simulator.xml” file, you can add it to your Historian Simulator Data Source by editing its “Definition” property, selecting your new XML file, and clicking “Save”.


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