FB_CTRL_RAMP_GENERATOR

FB_CTRL_RAMP_GENERATOR 1:

The function block provides a parameterizable ramp generator.

Description

This function block generates a ramp connecting the starting value fStart and the target value fTarget. The slope of the ramp (i.e. the velocity) is given in units/s by means of the fVeloPos and fVeloNeg parameters. The starting value is adopted when a rising edge appears at bEnable; calculation of the ramp then begins. As long as the signal bEnable remains TRUE the target value can be changed, and the output value changes, taking the form of a ramp as it moves from the current value to the presently active target value.

Behavior of the output value

FB_CTRL_RAMP_GENERATOR 2:

Inputs

VAR_INPUT
    bEnable  : BOOL;
    fStart   : FLOAT;
    fTarget  : FLOAT; 
END_VAR

Name	Type	Description
bEnable	BOOL	Start of ramp generation
fStart	FLOAT	Start value of the ramp
fTarget	FLOAT	Target value of the ramp

Outputs

VAR_OUTPUT
    fOut           : FLOAT;
    fVeloOut       : FLOAT;
    bValueReached  : BOOL;
    eState         : E_CTRL_STATE;
    eErrorId       : E_CTRL_ERRORCODES;
    bError         : BOOL;
END_VAR

Name	Type	Description
fOut	FLOAT	Output of the ramp generator
fVeloOut	FLOAT	Current velocity of the ramp generator
bValueReached	BOOL	This output indicates by going TRUE that the output `fOut` has reached the value `fTarget`.
eState	E_CTRL_STATE	State of the function block
eErrorId	E_CTRL_ ERRORCODES	Supplies the error number when the output `bError` is set.
bError	BOOL	Becomes TRUE as soon as an error situation occurs.

Inputs/ outputs

VAR_IN_OUT
    stParams    : ST_CTRL_RAMP_GENERATOR_PARAMS
END_VAR

Name	Type	Description
stParams	ST_CTRL_RAMP_GENERATOR_ PARAMS	Parameter structure of the ramp generator

stParams consists of the following elements:

TYPE ST_CTRL_RAMP_GENERATOR_PARAMS :
STRUCT
    tTaskCycleTime  : TIME; 
    tCtrlCycleTime  : TIME; 
    fVeloPos        : FLOAT; 
    fVeloNeg        : FLOAT; 
END_STRUCT
END_TYPE

Name	Type	Description
tTaskCycleTime	TIME	Cycle time with which the control loop is processed. This must be greater than or equal to the TaskCycleTime. The function block uses this input value to calculate internally whether the state and the output values have to be updated in the current cycle.
tCtrlCycleTime	TIME	Cycle time with which the function block is called. If the function block is called in every task cycle this corresponds to the task cycle time of the calling task.
fVeloPos	FLOAT	Velocity in unit/s, with which the output is changed from a lower value to a higher one.
fVeloNeg	FLOAT	Velocity in unit/s, with which the output is changed from a higher value to a lower one.