AxisLib

The AxisLib library provides a clean interface for basic motion control.

Every motion axis has a set of basic functionality in common. This includes powering and homing the axis, performing basic moves, and reading back status information. In addition to this basic functionality, every axis has its own set of specific functionality. Since it is impossible to make one piece of software that can handle both the common and specific functionality of any arbitrary axis, the software that handles common functionality must not interfere with axis-specific functionality.

The AxisLib library bundles the most common motion control commands and status information together into one clean interface. This leads to significantly faster development of motion applications. Also, the library is designed to work in parallel with any other motion functionality. This allows any application specific motion code to be layered on top of the basic functionality while still taking advantage of all the library has to offer.

Usage

The AxisLib functionality can be integrated into any project using a data structure and a function call.

Recommendations

In most applications, this function is useful for adminstration functions (Init, Homing, Error handling, Powering, User interface), however, we would encourage the user to create their own specific function blocks in their application code.

For example, use AxisLib to do Init, Home, and Power an axis. Use a user created MC_MoveAbsolute to do your process.

There are several reasons for this, but the main reason is for status information. If this structure is used directly, there is only 1 busy and 1 done, so the statuses are consolidated from all the function blocks. This makes it difficult to determine the state of your process based on an output from this structure. Using an instance created by the user means that the information on the PLCOpen block can be used reliably.

Initialization

The AxisLib library provides an interface to the acp10mc library, commonly referred to as PLCOpen motion control. This means that all of the steps to create a motion axis must still be followed. For details on this, please see the B&R motion control training manuals or the Automation Studio Online Help.

To use the AxisLib functionality, a variable must be declared of type AxisBasic_typ. This variable should then be initialized in the INIT routine of your program. This initialization consists of setting configuration settings and initial motion parameters.

BasicAxis.pAxisObject:=			ADR(gNCaxis);
BasicAxis.ErrorTextModuleName:=	'acp10etxen';

BasicAxis.IN.CFG.HomingPosition:=	0;
BasicAxis.IN.CFG.HomingMode:=		mcHOME_DEFAULT;

BasicAxis.IN.PAR.Position:=			0;
BasicAxis.IN.PAR.Distance:=			0;
BasicAxis.IN.PAR.Direction:=		mcPOSITIVE_DIR;
BasicAxis.IN.PAR.Velocity:=			1000;
BasicAxis.IN.PAR.Acceleration:=		10000;
BasicAxis.IN.PAR.Deceleration:=		10000;

BasicAxis.IN.PAR.JogVelocity:=		100;
BasicAxis.IN.PAR.JogAcceleration:=	10000;
BasicAxis.IN.PAR.JogDeceleration:=	10000;

BasicAxis.IN.CFG.StopDeceleration:=	10000;

The pAxisObject configuration setting contains the address of the ACP10AXIS_typ variable listed in the NC mapping table. This creates the link between the BasicAxis variable and the physical axis. Please see the motion training manuals or the Automation Studio Online Help for more information on NC mapping tables.

Cyclic Operation

To control the axis cyclically, the AxisBasicFn_Cyclic() function must be called in the CYCLIC routine of your program, once every scan, unconditionally. This function should not be called on the same BasicAxis variable more than once per scan.

AxisBasicFn_Cyclic( BasicAxis );

The BasicAxis can then be used as an interface for higher level motion sequencing programs.

CASE State OF

	ST_IDLE:

		BasicAxis.IN.CMD.Power:=	0;

		IF( Start )THEN

  			Start:=	0;

  			IF( 		BasicAxis.OUT.DriveStatus.ControllerReady
   				AND NOT	BasicAxis.OUT.DriveStatus.ControllerStatus
				)THEN
				
				State:=	ST_POWERON;

			END_IF

		END_IF
		
	ST_POWERON:
	
		BasicAxis.IN.CMD.Power:=	1;
				
		IF( BasicAxis.OUT.DriveStatus.ControllerStatus )THEN
  
			State:=	ST_HOME;
			
		END_IF
		
	ST_HOME:
	
		BasicAxis.IN.CMD.Reference:=	1;
		
		IF( 	BasicAxis.OUT.Done
  			AND	BasicAxis.OUT.DriveStatus.HomingOk
   			)THEN						
		
			BasicAxis.IN.CMD.Reference:=	0;
		
			State:=	ST_JOG;
			
		END_IF
	
	ST_JOG:
	
		BasicAxis.IN.CMD.JogForward:=	1;
			
		IF( Stop )THEN
  			
			Stop:=	0;

  			BasicAxis.IN.CMD.JogForward:=	0;
		
			State:=	ST_IDLE;
			
		END_IF
				
END_CASE

Reference

BasicAxis Data Structure

The main data structure of the AxisLib library is the BasicAxis structure (AxisBasic_typ datatype). This provides the interface to higher level programs and also stores all necessary internal information. It is divided into inputs (BasicAxis.IN), outputs (BasicAxis.OUT), a test interface (BasicAxis.TEST) and internals (BasicAxis.Internal).

Inputs

The BasicAxis inputs are divided into commands (IN.CMD), parameters (IN.PAR), and configuration settings (IN.CFG). Commands are used to initiate operations, and parameters and configuration settings determine how the commands will be processed. The difference between parameters and configuration settings is that configuration settings are generally set only once, while parameters might be set any time a command is issued.

Hard coded configuration

These are technically configuration parameters, but since they are typically not changed by users (or are addresses) they are removed from the CFG structure

pAxisObject - Address of the ACP10AXIS_typ variable listed in the NC mapping table. See the motion training manuals or the Automation Studio Online Help for details.
pEndlessPosition - Address of a permanent variable to use the InitEndlessPosition and mcHOME_RESTORE_POS homing method. If this value is non-zero, the position will be restored on startup.
ErrorTextModuleName - Name of the error text module for looking up error texts. See the motion training manuals or the Automation Studio Online Help for details.

Commands (.IN.CMD)

Power - Power the axis. If set to 1, the axis will be powered. If set to 0, the axis will be depowered.
Reference - Home the axis. Uses the HomingPosition and HomingMode parameters.
MoveAbsolute - Perform a move to an absolute position. Uses the Position, Velocity, Acceleration, Deceleration, and Direction parameters.
MoveAdditive - Perform an additive move. The Distance parameter is added to the current target position (NOT the current actual position). Uses the Distance, Velocity, Acceleration, and Deceleration parameters.
MoveVelocity - Perform a velocity move. The axis accelerates to the Velocity parameter and continues until another command is issued. If a new velocity is desired, the MoveVelocity command must be toggled. Uses the Velocity,
MoveCyclicPosition - Track the input position. When set to 1, the axis will continually track the input position. Uses the Position, Velocity, Acceleration, and Deceleration parameters. Acceleration, Deceleration, and Direction parameters.
JogForward - Jog the axis forward. The axis will stop when this command is reset. Uses the JogVelocity, JogAcceleration, and JogDeceleration parameters.
JogReverse - Jog the axis backwards. The axis will stop when this command is reset. Uses the JogVelocity, JogAcceleration, and JogDeceleration parameters.
Halt - Stops the axis. When set to 1, the axis while begin a command to zero speed. This command differs from stop, in that it can be interupted by new commands. Uses the StopDeceleration parameter.
Stop - Stops the axis. When set to 1, all other motion commands will be ignored and the axis will remain stopped. Uses the StopDeceleration parameter.
ClearReference - Clear the “Referenced” state of the axis. The axis HomeOk my remain true, but the Referenced output will be false, and the homing data will be cleared from the permanent memory and invalidated
AcknowledgeError - Acknowledge any errors or warnings on the axis.
Reset - Reset the axis after an axis error to get it out of axis error state
WaitToInitializeReference - Indicates that the axis should wait for the application before initilizing the reference routine. This may be required if the application dynamically sets the period or factor, for example.

Parameters (.IN.PAR)

Position - Position for absolute moves. [Units]
Distance - Distance for additive moves. [Units]
CyclicPosition - Cyclic position input for tracking set position. [Units]
Velocity - Velocity for absolute, additive, and velocity moves, and for tracking set positions. [Units/s]
Acceleration, Deceleration - Acceleration and deceleration for absolute, additive, and velocity moves, and for tracking set positions. [Units/s^2]
Direction - Direction for absolute and velocity moves. See the acp10mc library help for details.
JogVelocity - Velocity for jog moves. [Units/s]
JogAcceleration, JogDeceleration - Acceleration and declaration for jog moves. [Units/s^2]

Configuration Settings (.IN.CFG)

Name - Display name of the axis
Active - Activates the axis
HomingPosition - Actual position after homing the axis. [Units]
HomingMode - Mode with which to home the axis. See the acp10mc library help for details.
DefaultPosition - Defualt position if the endless position is invalid
StopDeceleration - Deceleration for stopping. [Units/s^2]
ReadCyclicPositionParID - ParID to use for Actual position if not the default
Factor - PLCOpen Scale Factor
Period - PLCOpen Axis Period

Hardware Inputs (.IO)

This function provides Input mapping for drives that do not have hardware inputs built in or that are not using the built in hardware inputs. In this case, standard IO module inputs can be used and forwarded to an axis. To use these mappings, the axis inputs must be configured in the axis init object to be ncFORCED. Any input that does not have ncFORCED will be ignored.

diHomeSwitch - Input Mapping for Home switch
diNegHWSwitch - Input Mapping for negative hardware limit switch
diPosHWSwitch - Input Mapping for positive hardware limit switch
diTrigger1 - Input Mapping for trigger 1
diTrigger2 - Input mapping for trigger 2

Outputs (OUT)

The BasicAxis outputs contain status information

Active - Indicates this function is active
ActualPosition - Current axis position. [Units]
ActualPositionPrecise - Current axis position. [Units]
ActualCyclicPosition - Current axis position. [Units]
ActualVelocity - Current axis velocity. [Units/s]
DriveStatus - Extended drive status information. See the help for the acp10mc library MC_DRIVESTATUS_TYP datatype for details.
PLCOpenState - Current PLCOpen state as booleans. See the motion training manuals or the Automation Studio Online Help for details.
Referenced - The axis has been properly referenced. This is set and reset by the application.
EndlessPositionInitialized - The endless position data has been initialized for the axis.
DataValid - The endless position data is valid.
Busy - Operation is currently being processed.
Done - Operation completed successfully. Done is reset when the input command is reset.
Warning - A warning exists for the axis. Warning is reset with the AcknowledgeError command.
WarningCount - Number of current warnings.
Error - An error exists for the axis. Error is reset with the AcknowledgeError command.
ErrorCount - Number of current errors.
ErrorID - Current error ID number.
ErrorString - Current error text information.

Test Interface

The test interface gives you direct access to the axis commands and parameters, interrupting any commands from higher level programs. This allows for easy testing of the axis during machine commissioning or servicing. The test commands and parameters are intended for use in an Automation Studio watch window and SHOULD NOT BE SET IN PROGRAMS.

Enable - If set to 1, TEST.CMD and TEST.PAR take priority over IN.CMD and IN.PAR. If set to 0, then TEST.CMD and TEST.PAR are ignored.
CMD - Test commands. See above for a full list of commands.
PAR - Test parameters. See above for a full list of parameters.
STAT - A reduced set of status information that is always available whether test mode is enabled or not.

Error ID Numbers

For a full list of motion errors and their descriptions, please see the Automation Studio Online Help.