S_PVGValveController (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_PVGValveController (FB)

Description

This function block controls Danfoss PVG32 voltage controlled proportional valves.

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
i_pEventCodePVGError = 0 OR
S_i_PosDirMaxPWMLevel out of range OR
S_i_PosDirMinPWMLevel out of range OR
S_i_CenterPositionPWMLevel out of range OR
S_i_NegDirMinPWMLevel out of range OR
S_i_NegDirMaxPWMLevel out of range

Initialization parameters

Parameter	Type	Unit	Range	Description
S_i_PosDirMaxPWMLevel	SAFEUINT	‰	0 - 1000	Defines PWM ratio when S_i_Control = 10000
S_i_PosDirMinPWMLevel	SAFEUINT	‰	0 - S_i_PosDirMaxPWMLevel	Defines PWM ratio when S_i_Control = 1
S_i_CenterPositionPWMLevel	SAFEUINT	‰	0 - S_i_PosDirMinPWMLevel	Defines PWM ratio when S_i_Control = 0
S_i_NegDirMinPWMLevel	SAFEUINT	‰	0 - S_i_CenterPositionPWMLevel	Defines PWM ratio when S_i_Control = -1
S_i_NegDirMaxPWMLevel	SAFEUINT	‰	0 - S_i_NegDirMinPWMLevel	Defines PWM ratio when S_i_Control = -10000
S_i_PosDirAscendRampTime	SAFEUINT	ms	-	Defines time how long it takes from ramped signal to change from center to max (0 to 10000).
S_i_PosDirDescendRampTime	SAFEUINT	ms	-	Defines time how long it takes from ramped signal to change from max to center (10000 to 0)
S_i_NegDirAscendRampTime	SAFEUINT	ms	-	Defines time how long it takes from ramped signal to change from center to negative max (0 to -10000 )
S_i_NegDirDescendRampTime	SAFEUINT	ms	-	Defines time how long it takes from ramped signal to change from negative max to center (-10000 to 0 )
S_i_PVGPullUpResistor	SAFEUDINT	Ω	-	PVG valve pull up resistor
S_i_PVGPullDownResistor	SAFEUDINT	Ω	-	PVG valve pull down resistor
S_i_PinPullUpResistor	SAFEUDINT	Ω	-	Control unit pin pull up resistor
S_i_PinPullDownResistor	SAFEUDINT	Ω	-	Control unit pin pull down resistor
S_i_DiagnosticDelay	SAFEUINT	ms	-	Diagnostic delay for PVG valve error signal.
i_pEventCode	POINTER TO EventCode	-	≠ 0	Pointer to application variable where event code is stored.
i_pEventCodePVGError	POINTER TO EventCode	-	≠ 0	Pointer to application variable where event code is stored.

Initialization method return value

TRUE: All initialization parameters ok.

FALSE: Error in initialization parameter(s).

Operation

POU is in normal operation mode if:

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

• The input parameters are valid and the input S_i_Control is inside its allowed limits AND

• Startup error is not detected AND

• PVG valve error is not activated

In normal operation the POU first ramp the input control value based on the given acceleration and deceleration parameters and the measured application cycle time.

The ramped value is scaled to output PWM ratio by using compensated PWM level parameters.

When the ramped value is 0 then the output o_PWMRatio is set to compensated center position value.

When the ramped value > 0 then o_PWMRatio is scaled to between compensated positive direction minimum and maximum level values.

When the ramped value < 0 then o_PWMRatio is scaled to between Compensated negative direction minimum and maximum level values.

The PWM level parameters are given as per mil from PWM maximum value G_PWM_OUT_MAXVALUE.

The constant G_PWM_OUT_MAXVALUE is HW dependent and it is defined in HW specific int library.

In normal operation the output o_ValveSupply is also set TRUE.

Operation in fault situations

The output o_PWMRatioControl is set to 0, o_ValveSupply and o_Status.OutputValid are set false, corresponding error bit is set in o_Status and corresponding EventID value is set to EventCode if:

• S_i_Control exceeds the allowed limits -10000- (+)10000 OR

• Input parameter i_pEventCode = 0 OR

• Input parameter i_pEventCodePVG = 0 OR

• PWM parameters exceeds the allowed limits or are not in consistent order OR

• compensated PWM level parameters exceed the allowed limits or are not in consistent order OR

• Startup error is detected i.e. S_i_Control ≠ 0 when i_Enable rises OR

• the PVG error signal is active for the diagnostic delay time

The output o_PWMRatioControl is set to 0, o_Status.OutputValid is set to false immediately if:

• i_Enable is FALSE

• A parameter error occurred.

The o_Status error bits and EventCode error are not reset before the rising edge of i_Enable input.

Inputs

Input variable name	Data type	Unit	Range	Description
i_Enable	BOOL	-	-	Enable POU operation.
S_i_Control	SAFEINT	-	-10000 - (+) 10000	Control value.
S_i_PVGError	SAFEBOOL	-	-	Error signal from PVG valve

Outputs

Output variable name	Data type	Range	Description
o_ValveSupply	BOOL	-	Valve supply output
o_PWMRatio	DWORD	0 - G_PWM_OUT_MAX_VALUE	Control value to PWM output.
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	o_PWM Ratio	o_Valve Supply	o_Status. OutputValid	o_Status error status	Event code FunctionID	Event code EventID
i_Enable TRUE AND init parameter error AND i_pEventCode NULL	0	FALSE	FALSE	ParameterError	-	-
i_Enable TRUE & Parameter error (i_pEventCode ≠ 0)	0	FALSE	FALSE	ParameterError	PVG_CONTROLLER	PARAMETER_ERROR
i_Enable TRUE AND init parameters ok AND S_i_Control in normal area (-10000- (+)10000)	PWM ratio	TRUE	TRUE	-	NO_FUNC	NO_ERROR
i_Enable TRUE AND init parameters ok AND S_i_Control > 10000	0	FALSE	FALSE	InputHigh	PVG_CONTROLLER	INPUT_TOO_HIGH
i_Enable TRUE AND init parameters ok AND S_i_Control < -10000	0	FALSE	FALSE	InputLow	PVG_CONTROLLER	INPUT_TOO_LOW
i_Enable TRUE AND init parameters ok AND S_i_Control in normal area (-10000- (+)10000) AND S_i_PVGError TRUE	0	FALSE	FALSE	PVGValveError	PVG_CONTROLLER	PVG_VALVE_ERROR