Use the fields within the Scaling section of the Analog Point tab to specify if, and how, Geo SCADA Expert scales the point values that are reported by the outstation.
ATTENTION: There are two levels of scaling that can be applied to a DNP3 analog point. The first level is scaling a raw value into an engineering value using linear interpolation. This level of scaling is applied only if the outstation returns integer values. At this level, if the outstation reports the value as a floating point value, Geo SCADA Expert ignores any configuration in the Raw Full Scale and Raw Zero Scale fields, regardless of the Enabled setting. The second level of scaling is where the Multiplier and the Offset values are applied. This second level of scaling is always applied.
- Enabled—This check box only applies to analog points for which the outstation reports the value as an integer.
Use the Enabled check box to determine whether the driver scales the integer values that are reported by the outstation.
Select the check box for the driver to interpret the reported value as a raw value. The driver uses the Raw Full Scale, Full Scale, Raw Zero Scale, and Zero Scale values to produce a scaled value. The driver then applies the appropriate Multiplier and Offset to the scaled value to produce a corresponding engineering value. It is this engineering value that Geo SCADA Expert uses for the point in the database.
When scaling is enabled, and the point value is not reported as a floating point value, any raw to engineering conversions performed by the outstation have to use the same Raw Full Scale, Full Scale, Raw Zero Scale, and Zero Scale values as those defined in Geo SCADA Expert.
Clear the check box for the driver to use the reported value without applying any scaling. The driver applies the appropriate Multiplier and Offset to the reported value, before updating the Geo SCADA Expert database with the resultant value.
- Raw Full Scale—Specify the raw integer value that the driver is to scale to the Full Scale value. The Full Scale value is specified in the Alarm Limits section of the Analog Point tab (see Alarm Limits).
- Raw Zero Scale—Specify the raw integer value that the driver is to scale to the Zero Scale value. The Zero Scale value is specified in the Alarm Limits section of the Analog Point tab (see Alarm Limits).
- Multiplier—Use to specify the amount by which the driver multiplies each point value. The driver applies the multiplier to the scaled value if scaling is supported and enabled, otherwise it applies the multiplier to the raw value. The driver then applies the relevant Offset to the value, before updating the Geo SCADA Expert database with the resultant value.
Leave the Multiplier at the default of 1 if the driver is not required to apply a different multiplier.
- Offset—Use to specify the amount that the driver is to add to, or subtract from, each point value once the Multiplier has been applied.
Specify a negative number if the driver is to subtract the specified amount from the point value.
Leave at the default of 0 if no other offset is required.