Use the fields within the Scaling section of the Analog Point tab to configure the scaling of a point. ClearSCADA applies scaling to each value that it receives from the device. This is in addition to any scaling that takes place at the device (see Configure SCADAPack 50 Device Point Properties).
- Enabled—This check box only applies to analog points for which the device receives an integer value.
If the device receives a floating point value, ClearSCADA ignores the Raw Full Scale and Raw Zero Scale settings, regardless of the Enabled setting.
Select the Enabled check box to specify that ClearSCADA should scale integer values. ClearSCADA uses the Raw Full Scale, Full Scale, Raw Zero Scale and Zero Scale values to produce a scaled value.
ClearSCADA will then apply the appropriate Multiplier and Offset to convert the scaled value to an engineering value.
Clear the check box if ClearSCADA should not apply any scaling to the integer values it receives from the device. ClearSCADA will still apply the Multiplier and Offset to the value.
Example:
ClearSCADA receives integer values from the device in the range 0 to 32760. You might want to convert the values so that they are in the range 0 to 100.
In this situation, you would set the Raw Full Scale to 32760 and the Raw Zero Scale to 0. You would set the Full Scale to 100 and the Zero Scale to 0. ClearSCADA would then scale the values to the range 0 to 100.
- Raw Full Scale—Enter the uppermost limit for a raw integer value that ClearSCADA receives from the device. ClearSCADA will scale this value to the Full Scale value. You can specify the Full Scale value within the Alarm Limits section of the tab (see Alarm Limits).
- Raw Zero Scale—Enter the lowest limit for a raw integer value that ClearSCADA receives from the device. ClearSCADA will scale this value to the Zero Scale value. You specify the Zero Scale value within the Alarm Limits section of the tab (see Alarm Limits).
- Multiplier—Specify the amount by which ClearSCADA should multiply a value. ClearSCADA then applies the relevant Offset. Leave the field set at the default of 1 if you do not want ClearSCADA to apply a different multiplier.
- Offset—Specify the amount that ClearSCADA should add or subtract from a value, once ClearSCADA has applied the Multiplier, to produce an engineering value. ClearSCADA then stores the result in the ClearSCADA database. Leave the field set at the default of 0 if you do not want to apply an offset.
Example:
You might set the Multiplier to 0.1 and the Offset to 5.
ClearSCADA applies this scaling to produce an engineering value.
For example, to scale a value of 45, ClearSCADA multiplies this value by 0.1, then adds 5 to the value (that is, (45 x 0.1) + 5 = 9.5). It then stores the result (that is, 9.5) in the ClearSCADA database.