Configure the Rate of Change Properties
The SCADAPack x70 tab on the Forms of SCADAPack x70 Analog Configuration items contains a Rate of Change section. Use the section to specify how the SCADAPack x70 device is to process analog data when the analog's value is rising or falling too rapidly for your requirements. When configured to do so, the device compares the current engineering value of the analog with its value over the specified time period and calculates the rate of change. It evaluates the rate of rise or fall whenever the analog's engineering value changes.
The properties in this section only apply if the analog is associated with a T_SPx70_ADV_ANALOG SCADAPack x70 logic variable (see Specify any SCADAPack x70 Logic Requirements).
The Rate of Rise and Rate of Fall fields are 'grayed out' and unavailable for use if the Period is set to 0. Such a time period disables the feature and indicates that rate of change detection is not to be performed.
- Rate of Rise—Use to specify the percentage of the analog's full scale, in engineering units, by which the value has to rise within the specified time Period. (You specify the analog's full scale using the Minimum Engineering value and Maximum Engineering value in the 'Scaling' section of the tab.) If the rate of change reaches or exceeds this percentage, the Rate of Rise Exceeded quality is set in the T_SPx70_ADV_ANALOG SCADAPack x70 logic variable that is associated with the analog.
Enter the required percentage, from 0 to 100. The default is 100, which indicates that this particular type of calculation is not to be performed.
- Rate of Fall—Use to specify the percentage of the analog's full scale, in engineering units, by which the value has to fall within the specified time Period. If the rate of change reaches or falls below this percentage, the Rate of Fall Exceeded quality is set in the T_SPx70_ADV_ANALOG SCADAPack x70 logic variable that is associated with the analog.
Enter the required percentage, from 0 to 100. The default is 100, which indicates that this particular type of calculation is not to be performed.
- Period—Use to specify the period of time (in seconds) over which the SCADAPack x70 device should calculate the analog's rate of change. Enter the required interval in the OPC Time Format. You can enter the value directly in the field, or use the Interval window (accessed via the field's browse button) to specify the required value.
The default of 0 disables the Rate of Change feature.