Topic: DMD0520

CTAXCFG - CTRIO2 Axis Configuration

Note: The CTAXCFG instruction can only be used with the CTRIO2 module.

The CTRIO2 Axis Configuration (CTAXCFG) instruction is used to define the characteristics of a profile that will be used by subsequent CTRIO2 Axis instructions.

The red triangle in the upper left corner indicates the CTRIO2 Axis Configuration (CTAXCFG) is a Fully Asynchronous instruction.

This instruction requires that the output channel that will be placed under Axis mode control is already configured for Pulse/Direction or CW/CCW pulse output mode by the System Configuration for the CTRIO.

Inputs:

The input is edge-triggered, meaning that each time this input logic transitions from OFF to ON, the CTRIO2 Axis Configuration (CTAXCFG) will run to completion, even if the input logic goes OFF before the operation is complete.

Parameters:

Note: Use the F9 key (Element Browser) or Down-Arrow key (Auto-Complete) at any time to see a complete list of the memory locations that are valid in the current field of the instruction.

Pulse Output Device - designates which of the pre-configured CTRIO2 Devices to interact with. Before this instruction can select a Pulse Output Device, a CTRIO2 Device must be configured with at least one of its output channels setup for Pulse/Direction or CW/CCW pulse output mode.

Part of the configuration for a device is assigning a name to the device. It is that name which will show up in the Pulse Output Device selection drop-down menu. For more information on configuring CTRIO2 devices go to the Module Configuration Section under System Configuration.

Note: no devices available - indicates that there are no CTRIO2 Devices that have been pre-configured to perform this instruction. Selecting 'create module' from the drop-down list will invoke the Create New Module Configuration dialog.

Note: create module - Selecting this will immediately pull up the System Configuration and allow the creation of a new module (see Module Configuration Section under System Configuration)

Pulse Output Structure - This field displays the name of the Pulse Output Structure that will be used by this instruction. This structure was created when the CTRIO2 module was configured during the Module Configuration phase.

Minimum Frequency - designates the starting frequency (in pulses per second) for the pulse output. This can be any positive constant value or any readable numeric location.

Maximum Frequency - designates the target frequency (in pulses per second) that the pulse output will ramp towards. This can be any positive constant value or any readable numeric location.

Acceleration Rate (pulses / sec2 ) - designates the rate at which the Minimum Frequency will to ramp toward the Maximum

Frequency. This can be any positive constant value or any readable numeric location.

Deceleration Rate (pulses / sec2 ) - designates the rate at which the Maximum Frequency will to ramp toward the Minimum Frequency. This can be any positive constant value or any readable numeric location.

Encoder Feedback - optionally selects which encoder feedback location to use and any required scaling of the encoder value.

• None - no encoder feedback will be used.

• Channel 1 - selects the encoder on CTRIO2 Channel 1

• Channel 2 - selects the encoder on CTRIO2 Channel 2
   

• Scale Factor (Pulse Output / Encoder) - designates optional scaling to account for different resolutions between the encoder and the stepper motor.
  
  This value is derived by dividing the encoder resolution (in pulses per revolution, after adjusting for X2 or X4 pulse counts) by the stepper motor resolution (also in pulses per revolution).
  
  This can be any positive constant value between 9.809089E-45 to 2,147,483,647 or any readable numeric location.
   

• Encoder Deadband (counts) - designates a number of pulses to use as a deadband around the target pulse count. This is helpful to prevent jitter of the stepper motor.
  
  This count value is applied equally above and below the target pulse count. A good minimum value is the number of encoder pulses that are generated by one stepper pulse, mathematically this equates to (2 / Scale Factor).
  
  This can be any positive constant value or any readable numeric location.

Initialize Output Position - optionally specifies whether to initialize the current position value (.OutputPosition) to the supplied value when this instruction is executed. This can be any positive or negative constant value or any readable numeric location.

On Success - designates which of the following actions to take if the CTRIO2 Axis Configuration (CTAXCFG) operation is successful, that is, the profile description is successfully loaded into the CTRIO2's memory, and the designated pulse output is in Axis mode.

• SET BIT - The specific BIT location will be turned OFF when the CTRIO2 Axis Configuration (CTAXCFG) instruction is first enabled, and then SET ON if the operation is successful. This value can be any writable bit location.
   

• JMP to Stage - JMP to the specified Stage. The target Stage must be in the same Program code block as the CTRIO2 Axis Configuration (CTAXCFG) instruction, you cannot specify a Stage in a different Program code block. This selection will function like a standalone Jump to Stage instruction. Click here for more information on the Jump To Stage instruction.

On Error - designates which of the following two actions to take if the CTRIO2 Axis Configuration operation is unsuccessful. For example if this instruction tries to target a CTRIO module (not a CTRIO2), or if the specified output device is not configured as a Pulse Output.
 

• SET BIT - The specific BIT location will be turned OFF when the CTRIO2 Axis Configuration (CTAXCFG) instruction is first enabled, and then SET ON if the operation is unsuccessful. This value can be any writable bit location.
   

• JMP to Stage - JMP to the specified Stage. The target Stage must be in the same Program code block as the CTRIO2 Axis Configuration (CTAXCFG) instruction, you cannot specify a Stage in a different Program code block. This selection will function the same as a standalone Jump to Stage instruction. Click here for more information on the Jump To Stage instruction.

Note: any time the On Error condition occurs, the CTRIO2 generates an Error Code that can be read in the <Module Name>.ErrorCode (Module Name is the name assigned to the CTRIO2 in the Module Configuration). The List of Error Code values (in decimal) follows:

Status Display:

The Status display of the CTRIO2 Axis Configuration (CTAXCFG) instruction shows:

• Values: .OutputPosition, Minimum Frequency, Maximum Frequency, Acceleration Rate, Deceleration Rate, (Pulse Output/Encoder) Scale Factor (if configured), Encoder Deadband (if configured), Initialize Output Position (if configured)
   

• Highlights: .OutputEnabled, .OutputActive, .Direction, .OutputSuspended, .OutputStalled bits
   

• ON/OFF: On Success, On Error bits

CTRIO2 Structure Field Care-Abouts:

The following is a list of the"dot" fields of the CTRIO2 structure that are programmatically used with the CTRIO2 Axis Configuration (CTAXCFG) instruction. To see a complete listing of all CTRIO structures and members, goto the Project Browser --> Configuration --> Memory --> I/O --> Specialty.

COLOR KEY

Blue: CTRIO2 Input

Maroon: CTRIO2 Output

Black: CTRIO2 Module

Silver: Not used for this instruction

Note: The red "x" is the digit 0, 1, 2, or 3.

See Also:

• CTRIO2 Axis Configuration
   

• CTRIO2 Axis Run Dynamic Position Mode
   

• CTRIO2 Axis Run Dynamic Velocity Mode
   

• CTRIO2 Axis Run Trapezoid
   

• CTRIO2 Axis Run Trapezoid w/ Limits
   

• CTRIO2 Axis Jog Mode

Example 1 of 2:

Description of a Typical CTRIO2 Axis Configuration (CTAXCFG) Stage Diagram:

To the right is a stage diagram of a simple sequence control that would move a motor to any number of positions and stop.

Initially the Config stage waits for Begin to come ON. When Begin comes ON, the CTRIO2 axis is configured and the process transitions to the Position stage.

The Position stage puts the CTRIO2 pulse output in the Dynamic Position mode. Once this is complete (Ready = ON) then the Move stage is enabled (not transitioned to). The reason for this is because the Position stage must remain enabled to keep the CTRIO2 pulse output in the Dynamic Position mode through the whole process.

The Move stage sets the CTRIO2's GotoPosition bit and waits for the AtPosition bit to come on indicating the pulse output has reached its position (Positioned = ON). Then the stage transitions to the InPos stage.

The InPos stage waits for either the NextMove or the Done buttons. If this was the last move, then the Done button converges both the Position and InPos stage and transitions to the Stop stage. If this was not the last move, then another position is given and the NextMove button transitions back to the Move stage.

The Stop stage simply exits this Program code block.

Description of a Typical CTRIO2 Axis Configuration (CTAXCFG) Stage Ladder:

To the right is the ladder equivalent of the above stage diagram that uses the CTAXDYNP instruction which will move a stepper motor attached to the CTRIO2's pulse output to any number of subsequent positions utilizing an axis configuration (CTAXCFG) profile, and then stop. Click here for more information on the CTAXDYNP instruction.

This example presupposes the existence of the following System Configuration for the CTRIO2 (PLC --> System Configuration --> Module Configuration(s) --> CTRIO_000 -->):

• Configure I/O --> Outputs --> Out0 --> Pulse (Step/Dir) or Pulse (CW/CCW).

• A stepper motor is wired to CTRIO2's Output 0 and Output 1.

Config is the initial stage which waits for the input Begin to come ON. It is assumed that the first position value is loaded into the Target variable before turning on the Begin bit. Once Begin comes ON the PositionEnable bit is set ON, the CTAXCFG instruction configures an axis and when it is finished it jumps to the Position stage.

Position is the main CTAXDYNP instruction stage. This stage remains enabled during all moves. Instead of transitioning to the next stage (Move), the next stage will merely be enabled. PositionEnable is already ON when first entering this stage and will enable the CTAXDYNP instruction. Then the following things occur:

1. The Pulse Output Device ($CTRIO_000_Out0) will be placed in the "Dynamic Position Mode."

2. The current position value ($CTRIO_000_Out0.OutputPosition) is set to 0 because the Current Position parameter is set to "Zero-out".

3. The CTRIO2's Pulse Output is enabled ($CTRIO_000_Out0.OutputEnabled = ON).

The PositionEnable bit will remain ON for all moves. It will be cleared OFF at the completion of the last move.

The CTAXDYNP's SUS (Suspend) input is controlled by the Suspend bit. This bit must remain OFF for any given move to complete. Turning this bit ON will cause the CTRIO2's output to decelerate and stop. Turning it back OFF will cause the CTRIO2's output to accelerate and complete a move.

The On Success parameter jumps to the Stop stage. This will occur when PositionEnable is cleared OFF and everything was successful.

The On Error parameter jumps to the ErrorStage stage. In this stage should exist logic (not shown here) that would properly handle the error (e.g. to process the $CTRIO_000.ErrorCode value).

Once the CTAXDYNP is enabled, the $CTRIO_000_Out0.OutputEnabled bit will be set ON by the Pulse Output Device (this could take a couple of scans). When this occurs the next stage (Move) is enabled.

Move stage accomplishes all moves. In order to do this the newest position value is assumed to be already written to the Target and the $CTRIO_000_Out0.GotoPosition bit is set ON. The Pulse Output Device will clear this bit when the move begins. Once the bit is cleared, then the $CTRIO_000_Out0.AtPosition bit is monitored for completion of the move. Once that bit is set ON by the Pulse Output Device, this move is complete and the Move stage transitions to the InPos stage.

The InPos stage waits for either the NextMove or Done bit. If this was not the last move, then a new position value is written to the Target variable and the NextMove bit is toggled. The NextMove bit resets itself OFF immediately just in case the move is so small that it completes before this bit can be manually turned OFF causing the program to oscillate between the Move and InPos stages. Setting NextMove ON causes a transition back to the Move stage. If this was the last move, then the Done bit is toggled. This disables the InPos stage and resets the PositionEnable bit.

The PositionEnable bit resets the CTAXDYNP instruction in the Position stage above. This causes the following to happen:

1. The CTRIO2 pulse output is disabled ($CTRIO_000_Out0.OutputEnabled = OFF).

2. The On Success transitions to the Stop stage.

The Stop stage merely exits this Program code block.

Example 2 of 2: