Linear-Motion FB

Summary of Linear-Motion FB

The default motion-values at the output of the Linear-Motion FB are equal to the Master Machine Angle.

Thus, the output continuously increases from 0 to 360, again, and again.

You can use the Linear-Motion FB to add or subtract a constant value from the MMA., so that motion-values at its output become 'before' or 'after' the Master Machine Angle.

Add and Edit Linear-Motion-FB



Kinematics FB toolbar > Linear-Motion FB [Right-side of Graphic-Area]


Add menu > Add Gearing FB


STEP 1: Add the Linear-Motion Function-Block to the graphic-area

1.Single-Click the Linear-Motion FB in the Kinematics FB Toolbar.
2.Single-Click again in the graphic-area to 'place' the FB in the graphic-area.

The Linear-Motion FB is now in the graphic-area.


STEP 2: Open the Linear-Motion Function-Block dialog-box:

1.Double-click the Linear-Motion FB in the graphic-area.

- or -

Linear-Motion FB dialog-box

The 'Function' of the Linear-Motion FB:

Output motion-value = Master Machine Angle + Constant

Optionally, select the Accumulate option, so that the output does not reset to 0 after each machine cycle.

The 'Function' of the Linear-Motion FB is then:

Output motion-value = (Revs * 360) + Master Machine Angle + Constant

Linear Motion FB dialog-box

Linear Motion FB dialog-box

Linear-Motion FB dialog-box:

1s-red Machine Angle +

Enter a motion-value in the Machine Angle + 'data box'.

In the example: the motion-value = '53.4'.

Thus, if the Master-Machine-Angle is '120', the output motion-value from the Linear-Motion FB = 120 + 53.4 = 173.4

When the Machine-Angle is made to be:
'Positive', then the output is 'before' [it 'leads'], the Master Machine Angle.
'Negative', then the output is 'after' [it 'lags'], the Master Machine Angle.

2s Output Options:

Reset after one Cycle [default option and most typical]
Output = Master Machine Angle + Value

- or -

Output = (Revs * 360) + Master Machine Angle + Value
3.Click the OK to close the dialog.

Notes on: 'Accumulate' or 'Reset after one Cycle' :

Generally, use Reset after one Cycle

Use 'Accumulate' when you want to model a watch, or a mechanism that does not have a motion-period equal to the Master-Machine-Angle.


You must use a Linear-Motion FB in the 'first' kinematic-chain in the 'first' Mechanism-Editor.

See Also:

Connecting FBs

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd