S_RefControlAndDiagnostics (FB)

Epec Programming and Libraries Manual

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Supported platforms: CODESYS 3.5, CODESYS 3.5 SAFETY

S_RefControlAndDiagnostics (FB)

Description

This function block diagnoses and controls reference voltage outputs. Reference voltage types depend on HW, 5V and 10V outputs are supported.

The function block uses internally S_ADCToVoltageOrCurrent function block to convert ADC values to voltage, and S_ValidateAI function block to validate voltage values.

Depending on the input parameter S_i_ReferenceType5V, the function block uses either VALUE_AT_AD_MAXIMUM.U_REF_5V or VALUE_AT_AD_MAXIMUM.U_REF_10V as voltage value at AD maximum value.

Also depending on the input parameter S_i_ReferenceType5V, the function block uses either G_REF_5V_OVERVOLT_LIMIT or G_REF_10V_OVERVOLT_LIMIT for diagnosing voltage high in both inputs.

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 OR
S_i_Tolerance < 0 OR
S_i_Tolerance > 1000 OR
S_i_DiagnosticDelay > 100

Initialization parameters

Parameter	Data type	Unit	Range	Description
S_i_Tolerance	SAFEDINT	‰	0 - 1000	Limit for voltage mismatch diagnosis.
S_i_ReferenceType5V	SAFEBOOL	-	-	Is used REF type 5V.
S_i_DiagnosticDelay	SAFEUINT	ms	0 - 100	Delay time for diagnostics.
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 (V1.4.1.0 or older)Operation (V1.4.1.0 or older)

The function block validates reference voltage by comparing measurement channel 1 with channel 2 and given high and low limits and that the channel voltages differ no more than given tolerance. The tolerance voltage is calculated per mil of channel 1 voltage. Tolerance is monitored only when REF control is active (i_RefControl = TRUE).

Short circuit and external voltage situations are diagnosed too.

The validated voltage is written to S_o_Voltage if:

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

• No fault (including initialization) has been diagnosed

Operation (V1.5.1.0 or newer)Operation (V1.5.1.0 or newer)

The function block validates reference voltage by comparing measurement channel 1 with channel 2 and given high and low limits and that the channel voltages differ no more than given tolerance. The tolerance voltage is calculated per mil of nominal reference voltage (5000mV or 10000mV depending on used REF mode). Tolerance is monitored only when REF control is active (i_RefControl = TRUE).

Short circuit and external voltage situations are diagnosed too.

The validated voltage is written to S_o_Voltage if:

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

• No fault (including initialization) has been diagnosed

Inputs

Input variable name	Data type	Unit	Range	Description
i_Enable	BOOL	-	-	Enable POU operation
i_RefControl	BOOL	-	-	Reference output control status request
i_ADValueCh1	DWORD	-	0 - G_ADC_MAXIMUM_VALUE	Measured channel 1 AD value
i_ADValueCh2	DWORD	-	0 - G_ADC_MAXIMUM_VALUE	Measured channel 2 AD value

Outputs

Output variable name	Data type	Unit	Range	Description
o_RefControl	BOOL	-	-	Reference output control status.
S_o_Voltage	SAFEDINT	mV	-	Validated reference voltage.
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	S_o_Voltage	o_RefControl	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	FALSE	ParameterError	REF_CONTROL	PARAMETER_ERROR
i_Enable TRUE AND init parameter error AND i_pEventCode NULL	0	FALSE	FALSE	ParameterError	-	-
i_Enable TRUE AND init parameters ok AND ( i_ADValueCh1 > G_ADC_MAXIMUM_VALUE OR i_ADValueCh2 > G_ADC_MAXIMUM_VALUE )	0	FALSE	FALSE	ParameterError	REF_CONTROL	PARAMETER_ERROR
i_Enable rises AND init parameters ok AND input valid	Calculated voltage of channel 1	i_RefControl	TRUE	-	NO_FUNC	NO_ERROR
i_Enable TRUE AND init parameters ok AND (channel 1 voltage > G_REF_5V_OVERVOLT_LIMIT OR channel 2 voltage > G_REF_5V_OVERVOLT_LIMIT)	0	FALSE	FALSE	Output High	REF_CONTROL	OUTPUT_TOO_HIGH
i_Enable TRUE AND init parameters ok AND i_RefControl TRUE AND voltages ok AND channel difference > tolerance	0	FALSE	FALSE	ValueMismatch	REF_CONTROL	DATA_MISMATCH
i_Enable TRUE AND init parameters ok AND i_RefControl FALSE AND voltages ok AND (channel 1 voltage > G_REF_EXT_VOLT_LIMIT OR channel 2 voltage > G_REF_EXT_VOLT_LIMIT)	0	FALSE	FALSE	ExternalVoltage	REF_CONTROL	EXTERNAL_VOLTAGE
i_Enable TRUE AND init parameters ok AND i_RefControl TRUE AND voltages ok AND (channel 1 voltage < G_REF_5V_SHORTCUT_VOLT_LIMIT OR channel 2 voltage < G_REF_5V_SHORTCUT_VOLT_LIMIT)	0	FALSE	FALSE	OverCurrent	REF_CONTROL	VOLTAGE_SHORTCUT

Example code

Function block is included in hardware specific diagnostic program.

It is automatically generated to code template when MultiTool Creator is used.

Reference voltage diagnostic is a safe-context POU.

Definitions:

VAR_INPUT

(* Reference Voltage Control Inputs *)

i_Enable: BOOL := FALSE; // Enable operation

i_RefVoltageControl: BOOL := FALSE; // Application request for 5V reference

i_5VRefChannel1: DWORD := DWORD#0; // Filtered ADC value for 5V reference

i_5VRefChannel2: DWORD := DWORD#0; // Filtered redundant ADC value for 5V reference

END_VAR

VAR_OUTPUT

(* Reference Voltage Control Outputs *)

o_RefControlStatus: EPEC_SHWD.Status; // FB status

o_RefControl_EC: EPEC_DITF.EventCode; // Event code

o_RefControl: BOOL; // 5V ref voltage control status for controlling FB function

S_o_RefVoltage: SAFEDINT; // Measured voltage

END_VAR

VAR

init_ok: BOOL; // Initialization status

refControl: EPEC_SHWD.S_RefControlAndDiagnostics; // POU instance

END_VAR

Init:

(* Reference voltage control and diagnostic *)

init_ok := refControl.Init(

S_i_Tolerance := G_IO.REFCONTROL_TOLERANCE, // Maximum voltage tolerance (per mil)

S_i_ReferenceType5V := TRUE, // Ref output nominal voltage 5V (FALSE = 10V)

S_i_DiagnosticDelay := G_IO.REFCONTROL_DIAGNOSTIC_DELAY, // Delay time (ms) for error diagnostic

i_pEventCode := ADR(o_RefControl_EC) // Event code pointer for FB

);

Code:

(* Reference voltage control and diagnostic *)

refControl(

i_Enable := i_Enable, // Enable operation

i_RefControl := i_RefVoltageControl, // Control request status

i_ADValueCh1 := i_5VRefChannel1, // Filtered ADC value for 5V reference

i_ADValueCh2 := i_5VRefChannel2, // Filtered redundant ADC value for 5V reference

S_o_Voltage => S_o_RefVoltage, // Measured reference voltage

o_RefControl => o_RefControl, // Reference voltage control status for FW function

o_Status => o_RefControlStatus // FB ststus

);