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Command Position

Mechaware API Documentation > Input

Overview

Overview

Description

The Command Position block is an Input block that is a source for Command Position data. The output from the Command Position block is the updated Axis Command Position value, the update rate is determined by the Evaluate Block.  

Example

The following example shows how to construct a PID Filter from scratch, the Command Position is used to generate a Position Error (by having Input 1 with a Gain of -1 on the summing junction), the Position Error is then sent into the PID Tree.

The following parameters are used to configure this block at load time:

 
AxisNumber

The number of the axis which is the source of the acceleration data. This number may be absolute or linked to the Model Number.

Evaluate Block This block allows you to specify whether the block executes Every Sample, Every Other Sample (Odd or Even), or Every Fourth Sample (and specify the First, Second, Third, or Fourth). This provides greater flexibility in controlling the execution of a model and to preserve performance for other areas of motion control.
User Defined Block Priority When selected, allows you to enter a Priority Code to modify Execution Ordering of this block. For more information, see Block Execution Order and User Defined Block Priority.
Priority For an explanation of how the Priority field is used by the MechaWare Model Downloader, see Block Execution Order and User Defined Block Priority.
User Data 0 Application-specific data. See User Data Storage.
User Data 1 Application-specific data. See User Data Storage.

Matlab/Simulink

Simulink Interface

cmdPosition1

The sim (opt) input is an input which only relates to simulation.

Note: This input is only used when simulating within Simulink and is ignored when the model is downloaded to a controller.

By supplying a value from a Simulink source or a trajectory generator that passes the value through the model, will allow you to see how the system responds given a Command Position. Additionally, allows you to to generate a Position Error when comparing to a simulated Actual Position block.

The Output of the Command Position block is the Axis Command Position value.

The Axis Number of the axis providing the position data is determined by the Axis Number parameter. This number can be absolute or linked to the model number.

The block has two user data fields (User Data 0, User Data 1) to store application-specific data for convenient storage and retrieval. See User Data Storage for details.

The block's update schedule is determined by the Evaluate Block. The following Parameter Dialog Box can be opened by double-clicking on the block in a Simulink Model:

cmdPosition2

 

C++ API

COMMANDBlock

Declaration

Public Method

  
class COMMANDBlock: public virtual Block
{
public:
	// User accessible coefficients
};
 

Required Header: mechaware.h

Description

The Command Acceleration block is used to connect the inputs of a model.

Methods

Block Methods

See Also

Memory
 Torque Output
Noise Generator MemoryOut
Actual Position Memory Out User Buffer
Command Position Scope
Position Error Feedback
Memory User Buffer Reset Status
Command Acceleration Test In
Command Velocity Test Out

 

 
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