OBIOMotionPwm (FB)

FUNCTION_BLOCK OBIOMotionPwm EXTENDS AbbLConCA

Single axis point-to-point or velocity movement, utilizing the PWM functionality for AC500 eco CPU.

precondition

the respective channel is configured as PWM channel.

Up to 8 PWM channel are possible. The max possible frequency is determined by hardware delay times.

Maximum possible frequency for channel 0..3 is 5kHz.

Maximum possible frequency for channel 4..7 is 100 kHz. Recommended is to use <50kHz, or combine the frequency calculation with a feedback like closed-loop control.

basic input parameters

OpenLoop

TRUE: There is no external position feedback available. The pulses output are used as actual position.

FALSE: A position feedback is used. The Actual position has to be written to ActPosition.

MaxFrequency

Used as a reference value to calculate the acceleration and deceleration. The axis will run from MinFrequency to MaxFrequency in RefAcceleration[ms] time.

MinFrequency

The movement will start and end with MinFrequency. The value should not be too small: 1Hz would mean the first/last step needs 1s.

Cycle

cycle time for the PLC program [ms]. A wrong setting for “Cycle” will result in wrong acceleration/deceleration ramps

p2p

provides the positioning method. It can either be of type OBIOBasicPoint2Point, which will use trapezoidal ramps, or of type OBIOSineSquaePoint2Point, which will use sinesquare ramps.

velocity movement

• A continuous velocity movement is started with a rising edge at ExecuteVel.

• The parameters used are RefFrequency, RefDirection, RefAcceleration and RefDeceleration.

• These paremeters can be changed during the movement and will be used immediately.

• The output InVelocity indicates that the required velocity is reached.

• The movement can be stopped with input Stop.

positioning movement

• A positioning movement can be started with a rising edge at ExecutePos. It is an absolute positioning.

• The parameters used are RefFrequency, RefAcceleration, RefDeceleration and RefPosition. No new values will be accepted during the movement.

• The output InPosition indicates that the movement is completed.

• The movement can be stopped with input Stop.

Note

This block should just be called once per cycle otherwise inconsistent values could be send to PRU, if send twice in short time.

InOut:

Scope	Name	Type	Initial	Comment	Inherited from
Input	Enable	BOOL	FALSE	A rising edge (Enable = TRUE) starts the operation, the output Busy goes to TRUE. All other inputs are read and considered continuously. A falling edge (Enable = FALSE) aborts the operation. During Aborting the Busy is still TRUE. Afterward all outputs are reset.	AbbLConCA
Output	Busy	BOOL	FALSE	Operation is running (while output Error is FALSE)	AbbLConCA
	Error	BOOL	FALSE	Operation is stopped with error (while output Busy is FALSE). This output is TRUE for at least one cycle or until Enable is set to FALSE. The output ErrorID gives more details about the error.	AbbLConCA
Input	Channel	BYTE		PWM channel, 0..7, requires according configuration
	OpenLoop	BOOL	TRUE	do not use the ActPosition as input if OpenLoop=TRUE is set. Instead, the number of pulses send to PWM will be written on ActPosition
	ResetPos	BOOL		Reset the position on rising edge to “0”, just allowed when Busy=FALSE
	ExecutePos	BOOL		start the algorithm with a rising edge, absolute positioning, just allowed with Busy=FALSE
	ExecuteVel	BOOL		start a continuous movement with a rising edge,just allowed with Busy=FALSE
	Stop	BOOL		Stop using RefDeceleration. Stop will overrule ExecutePos and ExecuteVel
	RefPosition	DINT		absolute position, where to move with rising edge at ExecutePos
	RefFrequency	DWORD		Reference Frequency in Hz, can be continuously changed for velocity movement
	RefDirection	BOOL		direction, used for velocity movement
	RefAcceleration	TIME	TIME#1s0ms	Acceleration as time in ms to run from MinFrequency to MaxFrequency
	RefDeceleration	TIME	TIME#1s0ms	Deceleration as time in ms to run from MinFrequency to MaxFrequency
	MaxFrequency	DWORD	100000	maximum frequency for frequency output, new value just used with Enable=FALSE
	MinFrequency	DWORD	500	minimum for frequency output, new value just used with Enable=FALSE
	Cycle	INT	1	Cycle time of the PLC-Program in ms, new value just used with Enable=FALSE
Inout	ActPosition	DINT		Actual position
Output	ErrorID	Error_ID		Error Code
	Active	BOOL		positioning is completed A new movement can just be started with Active=FALSE. Active is mutually exclusive with InPosition. A ExecutePos for the current position might result in InPosition without showing Active.
	InPosition	BOOL		positioning is completed
	InVelocity	BOOL		RefFrequency=ActFrequency
	ActFrequency	DWORD		moving frequency for the drive in inc/s. This value is send to the PWM channel (FB (INTERNAL)).
	ActDirection	BOOL		TRUE means: move forward. This output has to be connected to a binary output, to send the direction information to the stepper drive.
Inout	p2p	OBIOPoint2Point		provide interpolation method