FB_Ramp (Function Block)

Generates a ramp signal that rises or falls at a fixed rate indefinitely.

The output starts at StartValue and advances at Rate units per second. A positive rate produces a rising ramp, a negative rate a falling ramp. Changing Rate mid-run takes effect immediately.

Calling Reset() returns the output to StartValue.

Note

The block is FINAL and must be instantiated, not extended. Use FB_init to set fStartValue and fRate at declaration time.

Extends: FB_SoComponent

Properties

Rate

Type: LREAL

Gets or sets the rate of change in units per second.

A positive value produces a rising ramp, a negative value a falling ramp. Changes take effect immediately.

StartValue

Type: LREAL

Gets or sets the start value.

This is the output value the ramp returns to after a Reset().

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)
`fStartValue`	`LREAL`	Initial output value.
`fRate`	`LREAL`	Rate of change in units per second. Negative values produce a falling ramp.

Reset

Resets the output to the start value set in FB_init. The rate is unaffected.

Run

Advances the ramp by one time step.

Note

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