FB_CTRL_D
The function block provides a DT1 transfer element (a real D element) in a functional diagram.
Transfer function (continuous):
VAR_INPUT
VAR_INPUT
fIn : FLOAT;
fManSyncValue : FLOAT;
bSync : BOOL;
eMode : E_CTRL_MODE;
END_VAR
fIn : Input of the D element.
fManSyncValue : Input to which the D element can be synchronized, or whose value is present at the output in Manual Mode.
bSync : A rising edge at this input sets the D element to the value fManSyncValue.
eMode : Input that specifies the operation mode of the function block.
VAR_OUTPUT
VAR_OUTPUT
fOut : FLOAT;
eState : E_CTRL_STATE;
eErrorId : E_CTRL_ERRORCODES;
bError : BOOL;
END_VAR
fOut : Output of the D element.
eState : State of the function block.
nErrorID : Returns the ADS error number when the bError output is set.
bError: Becomes TRUE, as soon as an error occurs.
VAR_IN_OUT
VAR_IN_OUT
stParams : ST_CTRL_D_PARAMS;
END_VAR
stParams : Parameter structure of the D element. This consists of the following elements:
TYPE ST_CTRL_D_PARAMS
:
STRUCT
tCtrlCycleTime : TIME := T#0ms; (* controller
cycle time [TIME] *)
tTaskCycleTime : TIME := T#0ms; (* task cycle time
[TIME] *)
tTv : TIME := T#0ms; (* derivative
action time Tv *)
tTd : TIME := T#0ms; (* derivative
damping time Td *)
fOutMaxLimit : FLOAT := 1E38; (* maximum output
limit *)
fOutMinLimit : FLOAT := -1E38; (* minimum output
limit *)
END_STRUCT
END_TYPE
tCtrlCycleTime : 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.
tTaskCycleTime : Cycle time with which the function block is called. If the function block is called in every cycle this corresponds to the task cycle time of the calling task.
tTv : Differentiation time constant
tTd : Damping time constant
fOutMaxLimit : Upper limit at which the output of the D element is limited.
fOutMinLimit : Lower limit at which the output of the D element is limited.