The Concept of Time Zero.

All the early FXL DATA Loggers were designed in the mid 90's when memory chips had low capacity and were expensive. Because they all used small memories and a high sample rate of 100 samples per second, the recording times were short, from 11 seconds to 23 seconds, depending on the model of logger. There needed to be a technique of only recording the run. Almost all drag racing vehicles, whether car or bike, would go to the start line, stage and lock up either the transbrake in the transmission or line-lock the front brakes. To overcome these short recording times, FXL DATA wrote the software in the loggers to trigger from when the Wide Open Throttle was on and the transbrake or line lock or clutch switch was off.

picture of a graph with r p m traces and switch traces on it.

See the horizontal purple trace near the top of the chart. That is the full throttle switch. On the line below it, you will see a green trace that disappears at Time Zero when the driver has dumped the clutch. You will get the same traces from a bike when the rider dumps the clutch lever and launches.

NOTE that the older loggers had no internal battery to maintain the recording. If you turn the logger off, you lose the recording. You MUST download the recording before switching it off