Motion Arm Output Cam (MAOC)

The Motion Arm Output Cam (MAOC) instruction offers the functionality to set and reset output bits based on an axis position.

Motion Arm Functionality

Internally, Output Cam objects handle the Motion arm Output Cam functionality. Each Output Cam object is responsible for one output, which consists of 32 output bits. Each single output bit can be programmed separately with an Output Cam profile, and compensated for position offset and time delay.

The MAOC instruction initiates the arming of a specific Output Cam between the designated axis and output. When executed, the specified output cam bits are synchronized to the designated axis using an Output Cam Profile established by the

Logix Designer

Output Cam Editor. This relationship can be viewed as a master/slave relationship with the axis representing the master and the output bit representing the slave. Hence, the Output Cam functionality is related to the position cam functionality, which provides a relationship between a master axis and a slave axis.

To accurately synchronize the output cams to the designated axis, an execution schedule and associated axis and cam arm positions are specified. When the axis travels past the axis arm position in the direction specified by the Execution Schedule parameter, the cam position becomes locked to the axis position starting at the specified Cam Arm Position parameter. At this time, the output cam is armed and the Output Cam Armed status is set.  The output cam can also be configured via the Execution Schedule parameter to execute Immediately or Pending completion of a currently executing output cam. The output cam can also be executed Once, Continuously or Persistently by specifying the desired Execution Mode. Persistent behavior allows the output cam to become disarmed when the cam position exceeds the output cam range, and rearmed when cam position returns to within range.

Output Cam range is defined by input parameters CamStartPosition and CamEndPosition. The Master Reference selection allows axis input to be derived from either the Actual or Commanded position of the designated axis.

Available Languages

Ladder Diagram

Function Block

This instruction is not available in function block.

Structured Text

MAOC(Axis, ExecutionTarget, MotionControl, Output, Input, OutputCam, CamStartPosition, CamEndPosition, OutputCompensation, ExecutionMode, ExecutionSchedule, AxisArmPosition, CamArmPosition, Reference);

Operands

There are data conversion rules for mixed data types within an instruction. See

Data Conversion

.

Ladder Diagram and Structured Text

Structured Text

For the array operands, you do not have to include the array index. If you do not include the index, the instruction starts with the first element in the array ([0]). See

Structured Text Syntax

for more information on the syntax of expressions within structured text.

For the operands that require you to select from available options, enter your selection as:

MAOC Instruction

A valid Cam Arm position is any position, between and including, the Cam Start and Cam End positions. If the Cam Arm position is set to a value equal to (or very close to) the Cam Start or Cam End position, compensation may put a cam position out of range of the Cam Start and Cam End position. Compensation is affected by Output Compensation values specified for Position Offset, Latch Delay, and Unlatch Delay, as well as internal compensation values applied based on the Reference and Output parameters of the MAOC instruction.

No side effects occur if the MAOC instruction is configured with an Execution mode of Continuous or Persistent, and a pending MAOC instruction does not exist when the Output Cam is armed and the axis moves.

These side effects may occur if the MAOC instruction is configured with an Execution Mode of Once Only, and a pending MAOC exists when the Output Cam is armed and the axis moves.

One or more outputs may never change state.

The MAOC instruction may complete immediately.

One possible side effect of a pending MAOC instruction existing when the Output Cam is armed and the axis moves is that one or more outputs could begin executing based on the configuration of the pending MAOC instruction.

MOTION_INSTRUCTION Structure

Description

The Motion Arm Output Cam (MAOC) instruction executes an output cam profile set up manually, programmatically, or by the

Logix Designer

Output Cam Editor.  Internally, Output Cam objects handle Motion arm Cam functionality. Each Output Cam object is responsible for one output, which consists of 32 output bits.  Each single output bit can be programmed separately.  Currently Output Cam functionality is executed in the Logix controller every coarse update period (currently configurable between 1 and 32 ms).

Axis

The axis provides the position input to the Output Cam. The axis can be a virtual, physical or consumed one.

Execution Target

The execution target defines a specific Output Cam from the set that is connected to the specified axis. Currently, only eight Output Cams can be specified.

Specifying the Output Cam

To execute a MAOC instruction, a calculated Output Cam data array tag must be specified. Output Cam array tags may be created by the

Logix Designer

tag editor or the MAOC instruction using the built-in Output Cam Editor.  The data defines the specifics for each Output Cam element. The number of Output Cam elements is limited by the amount of available memory.  Zero or more cams can be defined for each output bit. There is no constraint on how these elements are arranged within the Output Cam array.

RefAn anomaly occurs when the output CAM ON window positions are redefined while the output controlled by the output CAM element is active. In some instances, the Motion Planner may not detect the off-crossing of the window and the output controlled by the output CAM element remains ON.er to the description of the OUTPUT_CAM structure for more information about data types and programming units.

This issue applies to any output point or virtual output controlled by an MAOC instruction.

Additionally, we recommend that you only change configuration when the CAM element is not active.

This diagram shows the relationships between the axis, input, and output that are defined by the Output Cam element.

Latch Type

Depending on the selected LatchType, the corresponding output bit is set according to this table:

This diagram shows the effect of the selected latch type on the output bit for different compensated cam and enable bit combinations as function of position.

Unlatch Type

This diagram shows the effect of the selected latch type on the output bit for different compensated cam and enable bit combinations as function of position.

This diagram shows the effect of the selected unlatch type on the output bit for different compensated cam and enable bit combinations as function of position.

This diagram shows the effect of the selected unlatch type on the output bit for different compensated cam and enable bit combinations as function of time.

Left and Right Cam Positions

The Left and Right cam positions define the range of an Output Cam element. If the latch or unlatch type is set to "Position" or "Position and Enable" with the enable bit active, the left and right cam positions specify the latch or unlatch position of the output bit.

Duration

If the unlatch type is set to "Duration" or "Duration and Enable" with the enable bit active, the cam duration specifies the time between the latching and the unlatching of the output bit.

Enable Type

Depending on the selected enable type, the enable bit is an element of either the input, inverted input, output, or inverted output.

Output Cam Array Checks

These output cam array checks are used with the MAOC instruction:

An Output Compensation data array tag may be specified via the

Logix Designer

tag editor. The data type defines the specifics for each output bit by specifying the characteristics of each actuator. The array indices correspond to the output bit numbers. The number of the highest compensated output bit defines the minimum size of this array. Changes to the output compensation take effect immediately.

This diagram shows the effect of the output compensation on the relationships between the axis, input, and output

Offset and Delay Compensation

The offset provides position compensation, while the latch and unlatch delay provides time delay compensation for the latch and unlatch operation. The following diagram shows the effect of the compensation values on an Output Cam element.

The cam range is defined by the left and right cam positions of the Output Cam element. The compensated cam range is defined by the cam range, offset, and latch and unlatch offsets. The latch and unlatch offsets are defined by the current speed v.

Latch Offset = v * Latch Delay

Unlatch Offset = v * Unlatch Delay

The resulting compensation offset can actually be larger than the difference between cam start and cam end position.

This equation illustrates the effect of the compensation values on the duration of an Output Cam element

Compensated Duration = Duration + Latch Delay - Unlatch Delay

Mode Compensation

Depending on the selected mode, the compensated output bit is set according to the following table.

This diagram shows the effect of the mode, cycle time, and duty cycle on an output bit.

Output Compensation Array Checks

This output compensation array checks are used with the MAOC instruction.

If you select a latch and unlatch delay combination that results in a compensated cam of less than minimum width, the width of the compensated cam is set to the minimum.

If you select a mode less than 0 or greater than 3, a Normal mode is considered and you are warned with an instruction error Illegal Output Compensation.

If you select a duty cycle less than 0 or greater than 100 and the mode is set to Pulsed or Inverted and Pulsed, a 0 or 100 duty cycle is considered and you are warned with an instruction error Illegal Output Compensation.

If you select a cycle time less than or equal to 0 and the mode is set to Pulsed or Inverted and Pulsed, the output bit is not pulsed and you are warned with an instruction error Illegal Output Compensation.

Output

The output is the set of 32 output bits that can be set and reset depending on the specified Output Cam. The output can be either a memory location or a physical output (for example, Local.0.O.Data).

Input

The input is the set of 32 input bits that are can be used as enable bits depending on the specified Output Cam. The input can be either a memory location or a physical input (for example, Local.0.I.Data).

Cam Start and Cam End Positions

The cam start and cam end positions define the left and right boundary of the Output Cam range. When the cam position moves beyond the cam start or cam end position, the behavior of the Output Cam is defined by the execution mode and execution schedule. Changes to the cam start or cam end position don’t take effect until the execution of a current MAOC instruction completes.

Execution Mode

Depending on the selected execution mode, the Output Cam behavior may differ, when the cam position moves beyond the cam start or cam end position.

Execution Schedule

Depending on the selected execution schedule, the Output Cam is armed according to the following table.

Axis Arm and Cam Arm Positions

The axis arm position defines the axis position where the Output Cam is armed, if the execution schedule is set to either forward only, reverse only, or bi-directional and the axis moves in the specified direction. The cam arm position defines the cam position that is associated with the axis arm position, when the Output Cam is armed. Changes to the axis arm or cam arm position only take effect after the execution of an MAOC instruction.

Reference

Depending on the selected reference, the Output Cam is connected to either the actual or command position of the axis.

In this transitional instruction, the relay ladder, toggle the Rung-condition-in from cleared to set each time the instruction should execute.

Affects Math Status Flags

No

Major/Minor Faults

None specific to this instruction. A major fault can occur if an uninitialized reference or a reference of incorrect type is passed to the Axis OperandSee

Common Attributes

for operand-related faults.

Execution

Ladder Diagram

Structured Text

Error Codes

See

Motion Error Codes (.ERR)

for Motion Instructions.

Extended Error Codes

Extended Error Codes provide additional instruction specific information for the Error Codes that are generic to many instructions. Extended Error codes for the Parameter Out of Range (13) error code lists a number that refers to the number of the operand as they are listed in the faceplate from top to bottom with the first operand being counted as zero. Therefore for the MAOC instruction, an extended error code of 4 would refer to the Output operand’s value. You would then have to check your value with the accepted range of values for the instruction. See

Motion Error Codes (.ERR)

for Motion Instructions.

Execution

Status Bits

MAOC Effects Status Bits

Status bits may be used to determine if an MAOC instruction can be initiated. The MAOC instruction affects the following status words in the Motion Axis Structure:

Each above is a DINT with bits 0 to 7 corresponding to the 8 execution targets. Bit 0 is execution target 0; bit 1 is execution target 1, etc.

If the Execution Schedule is set to Forward Only, Reverse Only or Bi-Directional, an MAOC instruction can be initiated when either of the following two conditions exist:

OutputCamStatus bit corresponding to execution target = FALSE

OutputCamStatus bit corresponding to execution target = TRUE

If the Execution Schedule is Pending, the MAOC instruction is initiated if either of the following two conditions exist:

OutputCamStatus bit corresponding to execution target = FALSE

OutputCamStatus bit corresponding to execution target = TRUE

Axis and Module Fault Conditions Disarm Output Cams

When the controller detects one of the following faults, it disarms output cams:

Those faults produce unreliable feedback data.

Also, if an axis fault exists when an MAOC instruction is initiated, the instruction errs.

Example

Ladder Diagram

Structured Text

MAOC(Axis1, ExecutionTarget1, MotionControl1, Output1, Input1, OutputCam1[0], CamStartPosition1, CamEndPosition1, OutputComp1[0], Persistent, Immediate, AxisArmPosition1, CamArmPosition1, actual);