PLCopen examples

Example: A function block instance controls different motions of an axis

The following figure shows an example where the function block (MC_MoveVelocity) is used to control AxisX with three different values of Velocity. In a Sequential Function Chart (SFC) the velocity 10, 20, and 0 is assigned to V. To trigger the input Execute with a rising edge the variable E is stepwise set and reset.

Fig23_Single_FB_SFC — Fig. 354: Single function block with SFC

The following timing diagram explains how it works:

Fig24_Timing_diagram_singel_FB — Fig. 355: Timing diagram for a usage of single function block

The second InVelocity is set for only one cycle because the Execute has gone low before the ActualVelocity equals CommandedVelocity.

Example: Different function blocks instances control the motions of an axis

Different instances related to the same axis can control the motions on an axis. Each instance will then be responsible for one part of the global profile.

Fig25_Cascading_FB — Fig. 356: Cascaded function blocks

The timing diagram:

Fig26_Timing_diagram_Cascading_FB — Fig. 357: Cascaded function blocks timing diagram

A corresponding solution written in LD looks like:

Fig27_Cascading_FB_LD — Fig. 358: Cascaded function blocks with LD