Creating a Rating Table

This procedure assumes that you have a source tag, for example, a tag holding water level data, from which you want to derive a value for another tag.

To create a new rating table:

Create a tag for the derived value

• In the site for the source tag, create a tag in the site's SYSTEM table to hold the value derived from the rating table.

  See Creating a new tag for more information.

Create a rating table

1. Click Rating Tables to open the Rating Tables module.
2. Click Add to create a new rating table.
3. Enter the following details:

   Property	Description
   Source Variable Tag	Specify the tag from which you want to read data (the X value).
   Derived Variable Tag	Specify the tag whose value you want to determine from the equation or table (the Y value).
   Equation	If you have been provided with an equation, select the Equation checkbox and enter the equation parameters.
   Minimum/Maximum Values	Specify the minimum and maximum values for an equation based rating table.
   Start/End Date	The start and end dates specify when the rating table is valid. By default, a rating table becomes valid when it is created and remains valid until it is updated, but you can set a specific validity period if you wish.
   Interpolation Method	Specify the interpolation method to use when calculating values that fall between points on a data points table. Interpolation can be linear or logarithmic.

4. Click Save to save your changes.

Add a table of points

If you are not using an equation, add points to the data points table.

• In the Points tab, either enter data points manually with the Insert function, or import a file of data points.