Tag History Bindings in Perspective

Tag History Binding Example

In this example, we'll use a Table component to show the records from some Tags that have Tag History enabled.

1. Drag a Table component onto a view. Select the Table component. 
2. In the Property Editor, click on the Binding  icon next to the data property.  The Edit Binding screen is displayed.
   
   
   
   
3. Select Tag History as the binding type.
4. In the Time Range section, select and the last 1 minute of data. 
5. Under the Select Tags section, click on the Tag icon. Navigate to the first Tag and click OK. Repeat for additional Tags. In our example, we chose the Sine0 and Sine2 Tags.
   
   
   
   
   
   
   
6. Notice the Binding Preview at the bottom of the screen. Click OK to save the Tag History binding.
7. Back in the view, the Table component now contains a column for the timestamp and one for each Tag. Notice how the timestamp does not have a date format. 
   
   
   
   
   
8. In order to change the t-stamp values into a date format, in the Property Editor under columns, click Add Array Element...
   
   
   
   
9. You'll notice that once the Array Element is added, the other two columns (Sine0 and Sine2) disappeared. We'll add them back in Step 10.
   1. In the field property, enter t_stamp (which is the column name).
   2. For the render property, select date from the dropdown.
   3. Select a dateFormat from the dropdown. In this example, we used the date time format.
      
      
      
      
      
10. Now, let's add the Sine0 and Sine2 columns back into our table by clicking on Add Array Elements... 2 times (refer to the yellow highlights in the image above). There is no need to change any of the Sine0 or Sine2 column properties unless you want to change the default settings or rearrange columns.  
    
    Notice that columns 1 and 2 (Sine0 and Sine2, respectively) are collapsed in this image. To see all the columns properties, expand the columns. 
    
    
    
    

Using Dynamic Tag Paths

Tag History bindings have the option to list out Tag paths, or to use an expression to build a Tag path. It is common to create a dynamic path or set of paths as a component property, that you then reference in other places. You can use as many Tag paths as you want, but they must all follow this format: 

• key [array] 

  • [0] {object}

    • aggregate value
    • alias value
    • path value
  • [1]{object}
    • aggregate value
    • alias value
    • path value
  • ...

 For an example, you can create a custom property on a chart and use it to fuel the historical data.

1. Create a custom property named Key on a chart component that is an Array type.

2. Copy and paste the JSON below into this Key property.

   JSON for Key Array

   [
     {
       "aggregate": "Average",
       "alias": "tank_temp",
       "path": "[default]Tank/03/Temperature"
     },
     {
       "aggregate": "Average",
       "alias": "setpoint",
       "path": "[default]Tank/03/Setpoint"
     }
   ]

3. Open the property binding on your chart and select the Tag History binding type. 
4. Select the Expression radio button to create your own tag structure.
5. Click on the property selector button on the right and find your new custom property. 
6. Click OK in the lower right.