StopWatch

Namespace: ZAux

Implements: IStopWatch

Simple clockrate-based stopwatch to measure time from one point in program to another one. It can be used for profiling the execution time of an algorithm and uses the CPU-Tick Count as lowest tick.

This implementations signature is based on MATLAB's way of measuring intervals. After instantiating the function block, the Tic method can be called to start the stopwatch. At any point Toc can be called to return the duration as LREAL. The duration is returned in the unit that is given as a parameter to the Toc method. The duration since starting the timer may be evaluated multiple times, only calling Tic resets the new base for the toc method of the stopwatch.

Note

The Stopwatch internally uses of the CPUs internal clock rate. While this is great for profiling, keep in mind that during breakpoints (used when debugging a PLC), the time keeps running and therefore, the duration increases. Also, since CPUs are not atomic clocks, the duration may differ from the actual duration by a bit.

Example

_stopwatch : ZAux.StopWatch;
_duration : LREAL;
---
_stopwatch.Tic();
ResourceHungryEvaluation();
_duration := _stopwatch.Toc(TimeUnit.Second);

FUNCTION_BLOCK StopWatch IMPLEMENTS ZCore.IStopWatch

Properties

Started

Returns TRUE if tic was called at one point in the application. This status can be reset with the Stop method. This bahavior is consistent with Timer.

PROPERTY Started : BOOL

Property Value

BOOL

Methods

Stop

Resets the stopwatch if started. After calling this method, Started will return FALSE. This behavior is consistent with Timer.

METHOD Stop ()

Tic

Starts the time measurement by saving the actual CPU-Tick-Count

METHOD Tic ()

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