Difference between current value and value at N period(s) ago.
Defines the time series data fed into the function. This can be a sensor ID or another function.
Number of data intervals considered in the function
*Input data is optional in most cases. If Info360 detects that the first input is time series data, it will be applied to the function. Otherwise, the current active sensor's data will be used, which is often the case in Reference Charts.
Example Usage as an Expression:
Change(7) - For daily data, this finds the difference between the current day from the same day the previous week.
Change(Lowest(24),168) - For hourly data, this will find the change between the lowest value of the day from the lowest value a week ago.
Example Reference Chart:
The following example shows how Change can be used to calculate the volume that has changed in the Tank (the equivalent of simply using the Volume function). Change(1) returns the change in tank level from the previous value. Next we multiply by 1104.47 ft^2 which is the tank area (the diameter is 37.5 ft).
This second example shows that the Change in Change can be a strong indicator of pumping operations. In the second panel, every positive spike in the Change(Change(1),1) represents the pump turning on, while negative spikes indicate the pump turning off.
For information on setting up custom equations and syntax, please refer to Analytical Functions.