What is a scaling object?

A scaling object maps one set of values to another set of values. Note that a scaling object is an internal object and therefore does not represent a physical process component.

Use

Use the scaling object when you need to map one set of values to another, instead of writing the necessary PLC code. The scaling object can be reused as many times as needed. You can use a scaling object to convert values from one measurement unit to another, for example, from °F (Fahrenheit) to °C (Celsius).

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How to define a scaling object

Click here $images\CHICLET.gif$ to learn how to define a scaling object.

Connecting a scaling object to an analog or a table object

When you need to scale an analog object or a table object with fixed values, you simply connect the scaling object to the appropriate object using the Scale As option on the Data Management tab in the object properties dialog box.

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No graphical display

Usually, a scaling object is not graphically represented on process diagrams, as the operator has no use for it during supervision. However, if you want to show the scaling object graphically, you are free to do so.

Scaling objects cannot be used as Master Objects in a Faceplate Master diagram.

How to view properties

Once the scaling object is defined, you can view its properties by -

Selecting Edit ® Open By Name, choosing Scaling and then selecting the name of the scaling object in the drop-down list beside the Name field.

If the scaling object is graphically shown on a diagram

double-click its symbol to view its properties.

The properties can be changed at any time and will be inherited by any analog or table object which is scaled with that object.

Type-specific properties

Each object type has its own type-specific properties. The scaling-specific properties can be viewed on the Scaling tab in the object properties dialog box. The most important ones are:

Property	Description
I/O value	Enter the input/output value you want to map to another value.
Real value	Enter the value you want to use instead of the input/output value.

In the example, the scaling object maps values within the area 4 to 20 onto values in the area 0 to 100. This means that when, for instance, the value 12 is sent to IGSS, the scaling object maps the value onto 50.