Examples

The following examples use a few channels and functions that are:

speed: The speed of the car in km/h
lapctr: The current lapnumber
HOLD: The last value calculated by this math-channel
dt: Time passed since the last calculated sample of this math-channel
sigma: Sums up the expression inside for the whole file up to the current sample

Example with sigma and dt - Integration over time

There is no function for integrating a channel over time. No matter, integration over time is simply the sum of a channel multiplied with the delta-time:

In this example, the speed is integrated over the file. The result is the distance driven (assuming the unit of speed is km/h, we have to divide by 3.6 to receive the distance in meters)

sigma(speed*dt) / 3.6

Example with delta and dt - Derivation of a channel

To derivate a channel by time, you have to divide the change of the channel by the change of time:

delta(channel)/dt

Example with HOLD - Filtering measurement errors

Assuming the speed of a car is between 0 and 400 km/h. If we want to clean the speed-channel from all measurement errors (values outside the valid speed-range) we have to find the error values.

If (speed <0 OR speed >400;0;speed)

Now every wrong value is set to 0. Instead of using this static value, you may want to keep the latest reasonable value. This can be accomplished by inserting the HOLD-function: HOLD returns the previous result of the math channel.

If(speed < 0 OR speed > 400; HOLD; speed)

Examples with sigma, lapsigma, dt, and delta - Calculating “highspeed”-duration for each lap

In this example, you are shown how to use these functions to generate a math channel that calculates the duration driven with more than 200 km/h for each lap. First thing to do is to sum up the time; the car is faster than 200 km/h.

sigma(if(speed > 200; dt; 0))

The if-function returns the time since the last sample when speed is greater 200 and 0 if not. Sigma sums up the results of the if-function to get the time past driving faster than 200 km/h.

Note:

This current function sums up the time for the whole file.

If you want the time being calculated for each lap individual, you have to reset the sum at the each laptrigger.

Unfortunately the sigma-function works on the whole file by default, so you need to reset the function after each lap. For that matter, the sigma-function has an optional reset condition.

Sigma(if(speed > 200; dt; 0); delta(lapctr) <> 0)

The new part in this function does exactly that. If the lap number changed (delta(lapctr) <> 0) sigma resets the sum back to zero and starts again.

Note:

Instead of delta (lapctr) you can also use {laptrig} <> 0.
Whatever your choice is, take care of the calculation period of your math channel. Especially {laptrig} is a single peak at the lap trigger and can be easily missed, if the calculation period is set to “Slowest channel”. Therefore using the lap counter is better, but again: If the period is “slowest channel” and your speed is measured faster, you have to select “fastest channel”!
For more information, see also “Computing Tab”.

There is a faster way to get the same results as well. Use LapSigma for resetting the sum at the beginning of a new lap.

LapSigma(if(speed > 200; dt; 0))

Example with DetectEvent - Brake Pressure

A Simple math function:

DetectEvent({pbrake_fl} > 10)

This generates an output with a non-zero value while the condition is true, in this case, the front brake pressure is greater than 10 bar. For one braking event, this looks like:

Rising Edge: The output is equal to a value of '1' for exactly one sample.
Event True: The output is equal to a value of '2' while the event is true (between the rising and falling edge)
Falling Edge: The output is equal to a value of '-1' for exactly one sample.

Detect Event Supports Multiple Overloads

Two additional arguments “BeginDelay” and “EndDelay” were added to DetectEvent. With these arguments DetectEvent delays state changes by the given amount of time.
The two arguments are optional and don’t change the signature of the “old” DetectEvent:

DetectEvent(Inactive|Rising|Active|Falling; <BeginCondition>; <BeginDuration>; <BeginDelay>; <EndCondition>; <EndDuration>; <EndDelay>)

The kind of the arguments are actually controlled by the given number of arguments. Hereby the first keyword argument (Inactive/Rising|Active|Falling) is always optional and is NOT counted as an argument!

DetectEvent with 6 Arguments

DetectEvent(