Demand to Delta Consumption (BDemandToConsumptionBlock)
The framework supports both trend and value requests. Value requests require access to trend data as their demand data source. Even though a value request does not include a time range, the block requests the previous 1 hour of trend data for the input source and searches for the last trend record prior to the current time.
Value requests require access to trend data as their demand data source. Even though a value request does not include a time range, the block requests the previous 1 hour of trend data for the input source and searches for the last trend record prior to the current time.
With value requests, the framework calculates consumption by taking the real-time value and using the time delta from the last record in the underlying trend.
Figure 117. Demand to Delta Consumption properties
To view these properties, double-click the block on the Wire Sheet or the block name in the Nav tree.
| Property | Value | Description |
|---|---|---|
| Out | read-only value slot | Outputs a calculated consumption value from the Trend In demand value. |
| Trend In | required value slot | Links from the output of other logic blocks or data sources to supply trend data to the current logic block. |
Example
Consider a power point (KW) with a 15-minute interval history. The current value of the point is 240 at 10:07:10 AM and the last record in the applicable history is from 10:00:00 AM.
Inputs: there are 3,600,000 milliseconds in one hour and the time difference is 7 minutes 10 seconds.
Calculations: (7 minutes * 60,000 milliseconds/minute) + (10 seconds * 1,000 milliseconds/second) = 430,000 milliseconds
consumption = demand * (time difference milliseconds / milliseconds in one hour) = 240 KW * (430,000 / 3,600,000) = 28.7 KWH
Figure 118. Demand to Delta Consumption algorithm
The screen capture shows the blocks used in the algorithm. The following Property Sheet shows how the Proxy Ext properties are configured.
Figure 119. Demand to Delta Consumption properties
Consider an electrical power history logged at 15-minute intervals with the following values:
Figure 120. Electrical power history values
The algorithm processes a demand value of 200.0 KW at 3:00 AM and returns a delta consumption value of 50.0 KWH at 2:45 AM. It offsets the consumption value backwards by one 15-minute interval indicating this would have been the consumption from 2:45 AM - 3:00 AM. The result is 200.0 KW of demand recorded at 3:00 AM.
A Px view might be configured with a table widget that uses an Analytic Table Binding configured as below.
Figure 121. Analytic Table Binding properties
The algorithm processes a demand value of 200.0 KW at 3:00 AM. The result generates the following table.
Figure 122. Table result
The algorithm returns a delta consumption value of 50.0 KWH at 2:45 AM. This consumption value is offset backwards one 15-minute interval indicating that 50.0 KWH would have been the consumption from 2:45 AM - 3:00 AM to result in the 200.0 KW demand being recorded at 3:00 AM.
demand * (15 minutes / 60 minutes) or simplified as demand * 0.25.