MLPmpRel

 Function A function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. - used to perform two subsequent relative moves.

Using the MLPmpRel function block, the PMP Generator is capable of producing forward-backward motions with a non-stop, jerk In physics, jerk is the rate of change of acceleration; more precisely, the derivative of acceleration with respect to time-free transition through zero speed (see Figure below). This feature is frequently useful for linear axes which must move back and forward without any pause at one end.

This function can also be used to do a single relative move, ending in zero speed, by setting the DeltaSecond argument to zero (0.0). If it is done, for the controlling speed to be the first move, the “Last_Travel_Speed” parameter has to be set equal to or greater than the “First_Travel_Speed” parameter.

In general, the slower of the two “Speeds” is utilized to optimize the S-curve behavior for the move whether it is a 2 or 1 delta move.

If the DeltaSecond argument is non-zero, it must have the opposite sign than the sign of the DeltaFirst argument.

Figure 7-104: PMP Generator Forward & Backward Motion Profile

Arguments

Input

BlockID	Description	ID Name of the PMP function block in the Pipe Network
	Data type	DINT
	Range	[-2147483648, 2147483648]
	Unit	N/A
	Default	—
DeltaFirst	Description	Length of first Move
	Data type	LREAL
	Range	—
	Unit	User unit
	Default	Value defined in the setup of a PMP Block within a Pipe Network. It is the “FIRST_TRAVEL_SPEED” field in the parameter tab.
DeltaSecond	Description	Length of second (return) Move
	Data type	LREAL
	Range	—
	Unit	User unit
	Default	Value defined in the setup of a PMP Block within a Pipe Network. It is the “LAST_TRAVEL_SPEED” field in the parameter tab.

Output

Default (.Q)	Description	Returns True if the MLPmlRel successfully completedSee Function - General Rules for more information.
	Data type	BOOL
	Unit	N/A

Related Functions

MLPmpWriteAccel

MLPmpWriteFstSpd

MLPmpWriteJerk

MLPmpWriteLstSpd

Example

Structured Text

//Execute a Relative move on a PMP Block name “PmpMaster” with a First Travel Speed of 750.0, Second Travel Speed of -500,
MLPmpRel( PipeNetwork.PmpMaster, 750 , -500);

Ladder Diagram

Function Block Diagram

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