MLMstAbs

• 
  
• This information applies to both MLAxisAbs and MLMstAbs.
  For simplicity, the term Axis Block also refers to Master Block.

When the Modulo is turned on, the Axis Block moves to the targeted position during the corresponding period Motor systems having a reciprocating or oscillating motor that operates synchronously with the periodicity of the source which supplies the electrical energy. The period of execution of a pipe is the time spent between two successive computations of set values for the same pipe. The period of execution of a pipe is specified by the PERIOD parameter of the input pipe block. and is calculated as:

• If the Position input is between 0 (zero) and the Modulo position, the Axis Block moves within the current period (no position rollover).
• If the Position input is greater than the Modulo position, the Axis Block moves during one of the next period (positive position rollover).

Figure 1: MLAxisAbs or MLMstAbs Modulo

The Axis Block works similarly for negative positions.

If the Position input is less than 0 (zero), the Axis Block moves during one of the previous period (negative position rollover).

Forcing the Direction of Rotation

In some applications, the direction The orientation components of a vector in space. of rotation for the axis is forced in one direction only.

As a consequence, the motor An actuator focused to a movement, converting electrical energy in a force or torque. movement goes to the next or previous modulo in these situations:

End Position is Less Than Start Position

If the End Position is less than the Start Position and the direction of rotation for the axis is forced to be clockwise, the red point shows when the Modulo position is reached.

See Row 2 of the MLMstAbs.

Figure 2: MLAxisAbs or MLMstAbs - End Position Less Than Start Position

End Position is Greater Than Start Position

If the End Position is greater than the Start Position and the direction of rotation for the axis is forced to be counter clockwise.

See Row 4 of the MLMstAbs.

Figure 3: MLAxisAbs or MLMstAbs - End Position Greater Than Start Position

Example Table

Start Position	End Position	Direction of Rotation	Cross Modulo	Position Input to MLAxisAbs (1)	RelativeDistance Moved (2)
60	200	Clockwise	No	200	140	(i.e., 200 - 60 + 0)
60	30	Clockwise	Yes	390	330	(i.e., 30 - 60 + 360)
60	30	Counter clockwise	No	30	-30	(i.e., 30 - 60 - 0)
60	200	Counter clockwise	Yes	-160	-220	(i.e., 200 - 60 - 360)

With:

(1) Position Input = End Position ( + Modulo * Direction of rotation)

(2) Relative Distance Moved = End Position - Start Position ( + Modulo * Direction of rotation)

Where:

Direction of rotation = 1 when clockwise and -1 when anti-clockwise.

Travel Speed Update with MLAxisAbs

The travel speed Speed is the absolute value of the velocity without direction. of the generator can be updated using the function block A function block groups an algorithm and a set of private data. It has inputs and outputs. MLAxisGenWriteSpd.

Depending on the state of the generator, this speed is directly reflected on the current move or a future move.

• If MLAxisAbs is not currently being executed, the new travel speed is applied for the trajectory Time dependent description of the path the TCP of an axes group moves along. Additional to the geometrical description of the space curve, time dependent state variables like velocity, acceleration, jerk, forces etc. are specified. calculation for a future MLAxisAbs command.
• If MLAxisAbs is currently being executed, and a new MLAxisAbs with the same target position is called, the new travel speed is taken into account only if the current state of the TMP Trapezoidal Motion Profile - This pipe block is a source block that frequently serves as a virtual master for a system composed of several pipes. Generally, a trapezoidal motion profile generator is used to generate a flow of values with a first derivative which produces a trapezoidal trajectory. profile is the constant velocity For a group of axes this means: In ACS the velocities of the different axes. In MCS and PCS it provides the velocity of the TCP or acceleration A change in velocity over time. Because velocity is a vector, it can change in two ways: a change in magnitude and/or a change in direction. In one dimension, acceleration is the rate at which something speeds up or slows down. However, more generally, acceleration is a vector quantity expressing the change with time of the velocity both in magnitude and in direction. See these Wikipedia articles for more information: http://en.wikipedia.org/wiki/Velocity http://en.wikipedia.org/wiki/Euclidean_vector http://en.wikipedia.org/wiki/Rate_(mathematics).
  • If the axis was decelerating to stop at the goal position the new travel speed is not taken into account.
• If a MLAxisAbs is currently being executed, and a new MLAxisAbs with a different target position is called, the new travel speed is taken into account.

Example 1

First MLAxisAbs. Second MLAxisAbs. Initial Speed. New Speed.

Figure 4: Initial speed is smaller than the new speed.

Example 2

First MLAxisAbs. Second MLAxisAbs. Initial Speed. New Speed.

Figure 5: Initial speed is bigger than the new speed.

Example 3

Acceleration. Constant Velocity. Deceleration.

Figure 6: The speed update is taken into account only if the second MLAxisAbs is triggered during acceleration or constant velocity.