S_CurrentRequest (FB)

Epec Programming and Libraries Manual

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Supported platforms: CODESYS 3.5, CODESYS 3.5 SAFETY, CODESYS 3.5 SP19 SAFETY

S_CurrentRequest (FB)

Description

This function block scales the input control signal -10000 - (+)10000 to current request.

Initialization

Init method is used to initialize the necessary static calculation parameters for the function block instance.

The method shall be called at least once before the actual function block can be called, i.e. at the application initialization phase.

The method checks the validity of input parameters. However, none of the function block outputs are affected by the initialization.

A parameter error is diagnosed if:

Init method is not called before the main FB call OR
i_pEventCode = 0 OR
S_i_MinimumCurrent is out of range OR
S_i_MaximumCurrent is out of range OR
S_i_MinimumCurrent >= S_i_MaximumCurrent

Initialization parameters

Parameter	Data type	Unit	Range	Description
S_i_MinimumCurrent	SAFEUINT	mA	0-5000	Minimum current value which is used in scaling.
S_i_MaximumCurrent	SAFEUINT	mA	0-5000	Maximum current value which is used in scaling.
S_i_PositiveControlDir	SAFEBOOL	-	-	True = Positive control signals are scaled to current request. False = Negative control signals are scaled to current request.
i_pEventCode	POINTER TO EventCode	-	≠0	Pointer to application variable which is type EventCode.

Initialization method return value

TRUE: All initialization parameters ok.

FALSE: Error in initialization parameter(s).

Operation

POU scales the input control value S_i_Control to output current request S_o_CurrentRequest based on the given minimum and maximum current request parameters and S_i_PositiveControlDir flag. If S_i_PositiveControlDir is true then positive input control signals are scaled to output current request and negative input signal sets the output S_o_CurrentRequest to 0.

If S_i_PositiveControlDir is false then negative input control signals are scaled to output current request and positive input signal sets the output S_o_CurrentRequest to 0

The block sets o_Status.OutputValid state TRUE if signals are valid and operation is enabled, i.e. i_Enable is TRUE.

Inputs

Input variable name	Data type	Unit	Range	Description
i_Enable	BOOL	-	-	Enable POU operation
S_i_Control	SAFEINT	-	-10000 - (+) 10000	Control value

Outputs

Output variable name	Data type	Unit	Range	Description
S_o_CurrentRequest	SAFEUINT	mA	0-5000	Current request
o_Status	Status	-	-	Status of output value. See Status structure.

Error diagnostic

See Diagnostic Interface library description of error status and event code functionality.

Conditions	S_o_Output value	o_Status. OutputValid	o_Status error status	Event code FunctionID	Event code EventID
i_Enable TRUE AND init parameter error AND i_pEventCode valid	0	FALSE	ParameterError	CURRENT_REQUEST	PARAMETER_ERROR
i_Enable TRUE AND init parameter error AND i_pEventCode NULL	0	FALSE	ParameterError	-	-
i_Enable TRUE AND init parameters ok	scaled current request value	TRUE	-	NO_FUNC	NO_ERROR
i_Enable TRUE AND init parameters ok AND S_i_Control > 10000	0	FALSE	InputHigh	CURRENT_REQUEST	INPUT_TOO_HIGH
i_Enable TRUE AND parameters ok AND S_i_Control < -10000	0	FALSE	InputLow	CURRENT_REQUEST	INPUT_TOO_LOW