Lag time is the delay between a change in the process and the time that changed sample actually reaches the analyser.
Why lag time matters
If lag is excessive, the analyser may be technically correct but operationally late. That reduces the usefulness of the measurement for control and troubleshooting.
What affects lag time
Transport line size, length, internal volume, flow rate, and sample system layout all influence lag.
How fast loops help
A fast loop keeps sample moving quickly through the transport path so the analyser sees fresher gas while using a controlled side stream for actual measurement.
Why this should be designed early
Lag problems are much easier to prevent in design than to solve after installation.
