MC_TouchProbe

 Function Block - Arms a Fast Input and returns the latched position when the Fast Input event occurs.

Inputs

Elements

Capture Engine

This is the drive capture engine to be used.

INT TriggerInput.InputID

InputID INT

Range = 0, 1

• 0 = Touch Probe 1 / Capture Engine 0
• 1 = Touch Probe 2 / Capture Engine 1

Trigger Direction

This is the input signal’s edge to capture.

INT TriggerInput.Direction

Range = 1, 2

• 1 = Rising edge.
• 2 = Falling edge.

• 
  
• Trigger Direction is also sent to the servo drive and is shown in the WorkBench Position Capture screen Edge setup.

Axis Number

This is where the input comes from.

INT TriggerInput.TrigID

Range = 0, 256.

0 = Trigger axis is to be the same as Axis.AXIS_NUM.

Trigger Mode

This is the capture method.

INT TriggerInput.TrigMode

Range = 0, 1

• 0 = Time based capture.
• 1 = Position based capture.
  • For position based capture, the TrigID must be the same as the AXIS_REF.

• 
  
  
• The Mode (either Time or Position) must be configured the same in the servo drive.
  This can be done either in:
  
  • COE Init commands and executed when the EtherCAT network is initialized (0x3460, subindex 3 and 4).
  • The WorkBench Positon Capture screen.

Outputs

Remarks

• 
  
• This function block starts a motion-related action and stores data for calculations and error checking.
  If using a dual-core controller, see Call Function Blocks Multiple Times in the Same Cycle.

• This function or function block does not generate any motion.
• See Function Blocks - General Rules about how inputs and outputs work.
• This function block captures an axis position
• When the Execute input transitions from low to high, the control requests the drive to arm its Fast Input to latch the axis position when a Fast Input occurs.
• The Axis input specifies which axis's position to latch and the TriggerInput input specifies which Fast Input to use and whether to trigger on the rising or falling edge of the Fast Input.
• When the Fast Input event occurs, the drive latches the axis's position.
  • This function block then returns the latched position at the RecordedPosition output and set the Done output high.
  • This process can be canceled with the AbortTrigger function block.
• If the WindowOnly input is high, the FirstPosition input and the LastPosition input define a window in which a Fast Input is accepted.
• Any Fast Input events that occur outside the window is ignored.

• 
  
• There are differences in how MC_TouchProbe interacts with AKD and AKD2G drives.
  See these topics for drive-specific information:
  • AKD Support With MC_TouchProbe
  • AKD2G Support With MC_TouchProbe

• 
  

• The accuracy of captured position data depends on the travel velocity. Please see the article MC_TouchProbe and Time-Based Capture on KDN for more information and how to correct for timing.

Example 1

If First Position ≤ LastPosition, the window in which a Fast Input is accepted is:

FastInputPosition ≥ FirstPosition AND FastInputPosition ≤ LastPosition

Example 2

If First Position > LastPosition, the window in which a Fast Input is accepted is:

FastInputPosition ≥ FirstPosition OR FastInputPosition ≤ LastPosition

This image shows the ladder diagram view of the MC_TouchProbe function block:

Figure 1: MC_TouchProbe

Fast Homing - Inputs

See these topics for more information:

• Fast Homing Example with the Pipe Network Motion Engine Axis Pipe Block
• Fast Homing Example with the PLCopen Motion Engine
• Fast Inputs with Pipe Network Motion
• Pipe Network Registration and Fast Homing
• Registration Position Capture Example with Pipe Network Trigger Block

Usage

This function block can be used to:

• Perform registration
• Determine the position of a product
• Measure product length

Limitations

• Both high speed inputs cannot be used at the same time.
• The TrigMode option is only used by MC_TouchProbe.

FBD Language Example

Not available.

FFLD Language Example

IL Language Example

Not available.

ST Language Example

(* MC_TouchProbe ST example *)
TriggerInputRef.InputID := 1;    //configure InputID
TriggerInputRef.Direction := 1;  //configure Direction
TriggerInputRef.TrigID := 0;     //configure TrigID
TriggerInputRef.TrigMode := 0;     //Capture trigger based on distributed clock time
Inst_MC_TouchProbe( ArmProbe, Axis1, TriggerInputRef, FALSE,0.0, 0.0 );
//Inst_MC_TouchProbe is an instance of MC_TouchProbe function block
ProbeIsDone := Inst_MC_TouchProbe.Done;            //store Done output into a user defined variable
ProbeValue := Inst_MC_TouchProbe.RecordedPosition; //store RecordedPosition output into a user defined variable

See Also

MC_AbortTrigger