MLFB_HomeFindHomeFastInputModulo

Pipe Network motion icon

Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Fast homing to a home switch: Modulo mode.

Inputs

Input	Data Type	Range	Unit	Default	Description
ibExecute	BOOL	0, 1	N/A	No default	Request the homing step procedure at the rising edge A rising edge is the transition of a digital signal from low to high. It is also called positive edge.
iAxisID	AXIS_REF	1, 256	N/A	No default	Name of a declared instance of the AXIS_REF library function. See AXIS_REF Structure for more information.
iPosition	LREAL	No range	User units	No default	Offset position applied after home switch is found.
ibDirection	BOOL	0, 1	N/A	No default	Defines the axis homing direction. 0 (zero) = Clockwise rotation. 1 = Counterclockwise rotation.
iVelocity	LREAL	No range	User unit/sec	No default	Commanded velocity for the homing move.
iAcceleration	LREAL	No range	User unit/sec²	No default	Commanded acceleration for the homing move.
iDeceleration	LREAL	No range	User unit/sec²	No default	Commanded deceleration for the homing move.
ibLimitSwitchMode	BOOL	0, 1	N/A	No default	Limit switch state to complete homing. 0 (zero) = Rising edge of switch. 1 = Falling edge of switch.
ibPosLimitSwitch	BOOL	0, 1	N/A	No default	The positive direction limit switch input I/O point.
ibNegLimitSwitch	BOOL	0, 1	N/A	No default	The negative direction limit switch input I/O point.
iTimeout	TIME	No range	Sec	No default	Maximum time for homing move to complete. If exceeded, the homing procedure errors out. 0 (zero) = no time limit.
ibFastInputNumber	BOOL	0, 1	N/A	No default	Limit switch state to complete homing. 0 (zero) = Fast Input The inputs are taken into account at each cycle depending on the system periodicity (for example each millisecond). Under certain circumstances this can be insufficient when more accuracy is needed, or if a quick response is required from the system. To fill the gap, a drive may have some Fast Input connections (generally one or two). When an event happens that triggers a Fast Input (e.g. when a sensor sends a rising edge), the detection of a signal occurs faster (which can be 1000 times more accurate than the system periodicity). Then the timestamp associated with this input can be provided to the IPC to take corrective action Number 1. 1 = Fast Input Number 2.
iCycleTime	LREAL	No range	Microseconds	No default	EtherCAT ***EtherCAT is an open, high-performance Ethernet-based fieldbus system. The development goal of EtherCAT was to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs cycle time. Either 250, 500, or 1000.

Outputs

Output

Data Type

Range

Unit

Description

obDone

BOOL

N/A

Indicates the move completed successfully.
The Command Position has reached the endpoint.

obActive

BOOL

N/A

Indicates this move is the Active move.

obError

BOOL

N/A

Indicates either:

An invalid input was specified.
The move was terminated due to an error.

oErrorID

DINT

N/A

Indicates the error if the Error output is set to TRUE.

Error identifier:

ErrorID	Description
1	Axis in error.
2	Axis is not enabled.
3	Timeout exceeded or expired.
4	SDO read/write error.
5	Input parameter out of range.

Remarks

Performs a single-axis home to a limit switch connected to a High Speed Input.
This function is used when the axis is set-up in Modulo mode.
The motor starts to move according to the direction setting.
- The home position has been found as soon as the fast input The inputs are taken into account at each cycle depending on the system periodicity (for example each millisecond). Under certain circumstances this can be insufficient when more accuracy is needed, or if a quick response is required from the system. To fill the gap, a drive may have some Fast Input connections (generally one or two). When an event happens that triggers a Fast Input (e.g. when a sensor sends a rising edge), the detection of a signal occurs faster (which can be 1000 times more accurate than the system periodicity). Then the timestamp associated with this input can be provided to the IPC to take corrective action selected is triggered on the edge selected.
An absolute move is made to the triggered position and the position value is set.
- The hardware limit switches are monitored during the homing procedure.
The drive behaves this way in case a hardware limit switch is active before the home-switch has been activated:
The motor changes the direction until the home switch is crossed.

This image shows the function or function block I/O.

Figure 6-87: MLFB HomeFindHomeFastInputModulo

Usage

This procedure performs a homing function searching for a sensor A sensor is a type of transducer that converts one type of energy into another for various purposes including measurement or information transfer using only High Speed Input Switches.
- A High Speed Limit Switch has 1 Off (or On) area.
Home is commanded by the user in the designated homing direction at the selected or programmed Velocity.
If LimitSwitch is found On with a rising Execute, the process is started in the opposite direction as specified.
If LimitSwitch is found Off Edge (released), the process is restarted again in original direction.
This can be On, depending on LimitSwitchMode setting.
- This ensures the end conditions are always the same.
The Timeout can cause an error if exceeded.

FBD Language Example

FFLD Language Example

IL Language Example

Not available.

ST Language Example

Direction:= 0;
Position:=1000;
Velocity:=1000;
Acceleration:=10000;
Deceleration:=10000;
SwitchMode:=0;
Timeout:=T#100;
FastInputNumber:=0;
CycleTime:=1000;

inst_fbHomeFindHomeFastInputModulo(True, Axis1, Position, Direction, Velocity, Acceleration, Deceleration, PosLimitSwitch, NegLimitSwitch, Timeout, FastInputNumber, CycleTime);

HomeComplete :=inst_fbHomeFindHomeFastInputModulo.Done;
HomeActive :=inst_fbHomeFindHomeFastInputModulo.Active;
HomeError :=inst_fbHomeFindHomeFastInputModulo.Error;
HomeErrorID :=inst_fbHomeFindHomeFastInputModulo.ErrorID;

(* PosLimitSwitch and NegLimitSwtch are declared I/O points *)