FC_CrankForwardTransformation

FC_CrankForwardTransformation - General Information

Overview

Type:	Function
Available as of:	V1.0.3.0
Versions:	Current version

Task

Forward transformation of a push crank

Description

From the angle of a push crank, this function calculates its linear position (kinematic transformation) and, from the torque engraved on the rotative side, the force resulting therefrom on the linear side (mechanical transformation). The meaning of the quantities involved can be taken from the following figure. The crank angle is measured in the mathematically positive sense (anti-clockwise), starting from the positive X direction.

It must be noted that there are cranks where it is not possible mechanically to move into all crank angles. If a mechanically non-permissible crank angle is specified, this function block issues the message q_etDiag = InputParameterInvalid and q_etDiagExt = AngularPositionRange.

NOTE: This function only serves for calculating the transformation of the crank. A transfer of position set values to axes does not take place. An advantage of this method is that the function can be combined with other mechanical calculation POUs without any problems.

Interface

Input	Data type	Description
i_lrRadius	LREAL	Length of crank radius in accordance with the above figure. Value range: > 0.0
i_lrPushRod	LREAL	Length of the crank push rod in accordance with the above figure. Value range: > 0.0
i_lrYOffset	LREAL	Position of the linear movement plane in relation to the X axis. Attention: This parameter is provided with a sign. If the plane is below the X axis, a negative value must be specified.
i_lrXOrigin	LREAL	User-defined zero position of the linear position. If i_lrXOrigin = 0.0, then the linear position is equal to the distance from the Y axis (= distance from the perpendicular through the crank fulcrum). However, in practice the zero point is to be positioned frequently in one of the two limit positions of the linear position, so that the linear position moves e.g. from 0.0 ... to X_max. This can be effected by specifying a suitable value for i_lrXOrigin (see figure above).
i_xCrankLeft	BOOL	This indicates in which direction the push rod of the crank is pointing. TRUE: Push rod shows in the negative X direction (towards the left in the figure) FALSE: Push rod shows in the positive X direction (towards the right in the figure)
i_lrAngularPosition	LREAL	Angle of the crank (rotative position). Unit: Degrees, value range: 0.0° ... 360°
i_lrTorque	LREAL	Torque engraved on the rotative side. The unit can be freely chosen; it must be noted, however, that a conversion factor may need to be used in order to obtain the output-side force q_lrForce in a specific unit (Example: selected unit for i_lrRadius, i_lrPushRod etc.: mm, selected unit for i_lrTorque: Nm. As a unit for q_lrForce this then yields Nm / mm = 1000 N.

Output	Data type	Description
q_etDiag	GD.ET_Diag	General library-independent statement on the diagnostic. A value not equal to ET_Diag.Ok corresponds to an diagnostic message.
q_etDiagExt	ET_DiagExt	POU-specific output on the diagnostic. q_etDiag = ET_Diag.Ok -> Status message q_etDiag <> ET_Diag.Ok -> Diagnostic message
q_lrLinearPosition	LREAL	Linear position calculated from the crank angle i_lrAngularPosition. Note: Depending on the specifications, the linear position may also assume negative values.
q_lrForce	LREAL	Output-side force calculated from the engraved torque i_lrTorque

Diagnostic Messages

q_etDiag	q_etDiagExt	Enumeration value	Description
OK	Ok	0	Ok
InputParameterInvalid	AngularPositionRange	65	AngularPosition is outside the valid range.
InputParameterInvalid	PushRodRange	64	PushRod is outside the valid range.
InputParameterInvalid	RadiusRange	21	Radius is outside the valid range.

AngularPositionRange

Enumeration name:	AngularPositionRange
Enumeration value:	65
Description:	AngularPosition is outside the valid range.

Issue	Cause	Solution
-	The outputs q_lrLinearPosition and q_lrForce cannot be calculated for the value defined for i_lrAngularPosition.	Verify i_lrAngularPosition Verify all parameters that are part of the calculation: i_lrRadius, i_lrPushRod, i_lrYOffset

Issue

Cause

Solution

The outputs q_lrLinearPosition and q_lrForce cannot be calculated for the value defined for i_lrAngularPosition.

Verify i_lrAngularPosition

Verify all parameters that are part of the calculation: i_lrRadius, i_lrPushRod, i_lrYOffset

Enumeration name:	Ok
Enumeration value:	0
Description:	Ok

The forward transformation has been completed successfully.

PushRodRange

Enumeration name:	PushRodRange
Enumeration value:	64
Description:	PushRod is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrPushRod, a negative value has been applied.	At the input i_lrPushRod, a value greater than 0 must be transferred.

RadiusRange

Enumeration name:	RadiusRange
Enumeration value:	21
Description:	Radius is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrRadius, a negative value has been applied.	At the input i_lrRadius, a value greater than 0 must be transferred.