Lag Source
All lag happens for a reason. For data-driven lag, you compensate for lag using a data point. This data point is called the Source of Lag, since it measures the reason the lag exists (ie. the distance between sensors).
This data point will almost always be either a counter or a rate.
Rate examples include…
- Production Line Speed
- Flow Rate
- Number of Products per Second*
Counter examples include…
- Distance Total
- Flow Total
- Production KPI (ie. Products Produced this Hour*)
*: For metrics such as 'products per second' or 'products this hour', we assume that each product is the same size/shape/distance apart.
By reviewing the value of this point, we can convert a particular amount (which we call a distance) into a time-difference, by calculating how long it to either count or total that much.
Example
For example, you may a conveyor system with two items 50m apart.
In this case, the source of our lag is the speed of the conveyor, and the distance between the two sensors is 50m.
We calculate the amount of lag between the two sensors by back-calculating how long it took 50m to pass based on the conveyor speed.