S_AIOverCurrentProtection (FB)

This function block is used for protection of a current mode input from over current.

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 is not called before the main FB call OR
i_pEventCode = 0

Initialization parameters

Parameter	Data type	Unit	Range	Description
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

The block sets o_Status.OutputValid state TRUE if:

• The control is enabled, i.e. i_Enable is TRUE and

• No fault (including initialization) has been diagnosed

If the diagnosed AI pin is set to operate in current mode, and S_i_Current value is over G_AI_OVERCURRENT_LIMIT continuously over G_AI_OVERCURRENT_DIAG_DELAY time, then

• The diagnostic statuses o_Status.OutputValid is set FALSE, o_Status.OverCurrent error is set TRUE and the corresponding EventID is set to i_pEventCode.

If S_i_Current input value is under 0 when i_Enable is TRUE, then

• Immediately the diagnostic statuses o_Status.OutputValid is set FALSE, o_Status.ParameterError error is set TRUE and the corresponding EventID is set to i_pEventCode.

The application must set the pin to voltage mode with FW-provided function.

Inputs

Input variable name	Data type	Unit	Range	Description
i_Enable	BOOL	-	-	Enable POU operation
S_i_Current	SAFEDINT	uA	>=0	Measured current of input

Outputs

Output variable name	Data type	Range	Description
o_Status	Status	-	Status of output value. See Status struct.

Error diagnostic

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

Conditions	o_Status. OutputValid	o_Status error status	Event code FunctionID	Event code EventID
i_Enable TRUE AND i_pEventCode valid AND S_i_Current < 0	FALSE	ParameterError	AI_OC_PROTECTION	PARAMETER_ERROR
i_Enable TRUE AND i_pEventCode NULL	FALSE	ParameterError	-	-
i_Enable rises AND i_pEventCode valid AND S_i_Current <= G_AI_OVERCURRENT_LIMIT	TRUE	-	NO_FUNC	NO_ERROR
i_Enable TRUE AND i_pEventCode valid AND S_i_Current > G_AI_OVERCURRENT_LIMIT	FALSE	OverCurrent	AI_OC_PROTECTION	INPUT_TOO_HIGH

Example code

When enabling IO configuration on-the-fly, the firmware turns the safety switch off.

S_AIOverCurrentProtection FB is included for current inputs in Multitool Creator code template.

Safety Definitions:

Result: EPEC_SYSTEM.SYSTEM_ERROR_CODES:= EPEC_SYSTEM.SYSTEM_ERROR_CODES.FW_ERR_OK;

PIN_1_03_OC: EPEC_SHWD.S_AIOverCurrentProtection;

PIN_1_03_OC_Status: EPEC_SHWD.Status;

PIN_1_03_OC_EC: EPEC_DITF.EventCode;

Safety Init:

PIN_1_03_OC_EC.DeviceID := BYTE#1;

PIN_1_03_OC_EC.ChannelID := BYTE#3;

PIN_1_03_OC_EC.FunctionID := EPEC_DITF.FunctionIDs.NO_FUNC;

PIN_1_03_OC_EC.EventID := EPEC_DITF.ErrorIDs.NO_ERROR;

PIN_1_03_OC.Init(

i_pEventCode := ADR(PIN_1_03_OC_EC)

);

Safety Code:

PIN_1_03_OC(

i_Enable := TRUE,

S_i_Current := PIN_1_03_Current, (* Mapped to pin current feedback in io_interface *)

o_Status => PIN_1_03_OC_Status

);

(* Pin overcurrent -> set to voltage mode *)

IF PIN_1_03_OC_Status.OverCurrent THEN

Result := EPEC_IODRV.IoDrvDOSetConfig(EPEC_HW.IO_Channels.PIN_1_03_DO_TYPE_V_mA,FALSE);

END_IF