FB_SawtoothWave (Function Block)

Generates a sawtooth wave signal.

The output rises linearly from -Amplitude to +Amplitude over one full cycle then resets instantly, or falls from +Amplitude to -Amplitude depending on Direction. Bias shifts the output vertically.

Phase shifts the wave horizontally in radians. Negative values shift in the opposite direction.

Note

The block is FINAL and must be instantiated, not extended. Use FB_init to set tPeriod, fAmplitude, fBias and fPhase at declaration time.

Extends: FB_PeriodicSignal

Properties

Direction

Type: E_RampDirection

Gets or sets the direction of the sawtooth.

Rising ramps from -Amplitude to +Amplitude before resetting. Falling is the inverse. Changes take effect immediately.

Methods

FB_init

Inputs

Name	Type	Description
`bInitRetains`	`BOOL`	if TRUE, the retain variables are initialized (warm start / cold start)
`bInCopyCode`	`BOOL`	if TRUE, the instance afterwards gets moved into the copy code (online change)
`tPeriod`	`LTIME`	Duration of one full cycle.
`fAmplitude`	`LREAL`	Scales the wave. Output swings between Bias ± Amplitude.
`fBias`	`LREAL`	Shifts the output vertically.
`fPhase`	`LREAL`	Phase offset in radians. Shifts the wave horizontally.

Reset

Restarts the wave from the beginning by resetting the accumulated time to zero. The phase, amplitude, and bias are unaffected.

Run

Advances the sawtooth wave by one time step.

Note

Must be called once per cycle on a single PLC task. If the measured cycle time is zero or Period is zero, the method returns early without updating the output.