About Limits

Upper and lower limits can be applied to the command values in a mechanism. These limits are enforced for all mechanism simulations (including those performed in the Mechanical Systems Experienceapp). Limits are useful for preventing unrealistic configurations in a mechanism, such as an offset distance that extends a component past the physical dimensions of the mechanism.

Limits can be defined as part of an engineering connection definition, or they can be assigned in the Mechanism Player.

This page discusses:

Define Limits in Engineering Connections

Limits are defined for a controlled constraint in an engineering connection using the Lower and Upper columns in the Engineering Connection Definition dialog box.

For more information, see Creating Engineering Connections for Mechanisms. Limits defined as part of an engineering connection take precedence over any other limits applied to that connection.

Define Limits in the Mechanism Player

If limits are not defined in the engineering connection, default limits are assigned in the Mechanism Player.

  • For offset-based commands (cylindrical or prismatic connections), the default limits are 100 above and 100 below the initial value of the command.
  • For angle-based commands (cylindrical or revolute connections), the default limits are 360° above and 360° below the initial value of the command.
  • For curve-based commands (point curve, roll curve, or slide curve connections), the default limits are zero and the length of the curve. If the curve forms a closed loop, then the limits are defined relative to the initial value of the command. The lower limit represents the beginning of the curve and the upper limit represents the end of the curve. For example, for a curve with a length of 100, the initial values result in the following limits:
    Initial Command Value Limits
    10 0, 100
    110 100, 200
    210 200, 300
    –10 –100, 0

You can change the limits in the Mechanism Player by right-clicking the value box and selecting Range > Edit from the menu that appears. However, if you define limits in the engineering connection later, the engineering connection limits take precedence over any limits defined in the Mechanism Player.