Motion Arm Registration (MAR)

Use the Motion Arm Registration (MAR) instruction to arm registration event checking for the specified axis. When the instruction is called, a registration event is armed based on the selected Registration Input and the specified Trigger Condition. When the specified Registration Input transition satisfies the Trigger Condition, the axis computes the axis position at the moment the event occurred based on hardware latched encoder count data and stores it in the associated Registration Position variable in the axis data structure. Also, the instruction’s Event (PC) bit is simultaneously set, as well as the Registration Event Status bit in the axis data structure. If Windowed Registration is selected, only registration events whose computed registration position falls within the Max and Min Position window are accepted. If the Registration Position falls outside this window the registration event checking is automatically rearmed.

Available Languages

Ladder Diagram

Function Block

This instruction is not available in function block.

Structured Text

MAR(Axis,MotionControl, TriggerCondition, WindowedRegistration, MinimumPosition, MaximumPosition, InputNumber);

Operands

Ladder Diagram

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:

MOTION_INSTRUCTION Structure

Description

The MAR instruction sets up a registration event to store the actual positions of the specified physical axis on the specified edge of the selected dedicated high speed Registration input for that axis.

When an MAR instruction is executed, the RegEventStatus bit is set to 0 (FALSE) and the selected Registration input for the specified axis is monitored until a Registration input transition of the selected type (the registration event) occurs. When the registration event occurs, the RegEventStatus bit for the axis is set to 1 (TRUE) and the Actual Position of the axis is stored in the Registration Position variable corresponding to the registration input (for example, Registration 1 Position 1 or Registration 2 Position).

Registration

Multiple registration events may be active at any time for a given axis, but only one may be active per registration input. Each event is monitored independently and may be checked using the appropriate RegEventStatus bit.

Windowed Registration

When the Windowed Reg checkbox is checked, the selected trip state only results in a registration event if it occurs when the axis is within the window defined by the minimum and maximum positions as shown below.

Enter values or tag variables for the desired absolute positions that define the position window within which the selected trip state of the Registration input is valid. Windowed registration is useful in providing a mechanism to ignore spurious or random transitions of the registration sensor, thus improving the noise immunity of high-speed registration inputs.

For linear axes, the values can be positive, negative, or a combination. However, the Minimum Position value must be less than the Maximum Position value for the registration event to occur. For rotary axes, both values must be less than the unwind value set in the motion controller’s machine setup menu. The Minimum Position value can be greater than the Maximum Position value for registration windows that cross the unwind point of the axis, as shown below.

Position Window for Rotary Axis

Rearming an MAR Instruction

If your application requires rapid and continuous detection of a registration sensor, we recommend using this logic:

Ladder Logic for Continuous Registration Detection

To rearm the MAR instruction, the rung must change from false to true. The rate at which this logic functions depends on:

To successfully execute a MAR instruction, the targeted axis must be configured as either a Servo or Feedback Only axis. Otherwise, the instruction errs.

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 Operand. See

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. The following Extended Error codes help to pinpoint the problem when the MAR instruction receives a Servo Message Failure (12) error message. See

Motion Error Codes (.ERR)

for Motion Instructions.

Extended Error codes for the Parameter Out of Range (13) error code work a little differently. Rather than having a standard enumeration, the number that appears for the Extended Error code 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 MAR instruction, an extended error code of 4 would refer to the Min Position value. You would then have to check your value with the accepted range of values for the instruction.

Status Bits

MAR Changes to Status Bits

Example

Ladder Diagram

Structured Text

MAR(Axis1, MAR_2, Positive_Edge, enabled, minmarpos_1, maxmarpos_1, 1);