STEP 7 V14 – Simple Sample: passing arrays without size pre-definition (array[*])

“Simple Samples” are small projects that demonstrate simple features. The target is give a quick overview about the theme and be used as start point for related discussions. Follow there are a short description and the configuration main steps.

Description:

One of news of TIA V14 is the possibility todefine arrays with no pre defined size as block parameter (Array(*) as new parameter data type).

New instructions (LOWER_BOUND, UPPER_BOUND are available to determining the array boundaries.

This make be possible to build general proposes block that automatically adapts by itself by usage.

Benefits

• Pointer programming for arrays of varying lengths no longer necessary
• Better runtime performance than pointer (Any/Variant) and copying by MOVE_BLK
• Fully symbolic and improved readability
• Enables generic standard functions for arrays varying in length

This sample program shows a block (Block_1) that calculate the average value of a array of data:

Tips:

• The array is passed as a whole, as InOut block parameter.
• To define the variable data type, first select “array [0..1] of” after that select the “v” button, select the data type and in the “array limits” type “*”
• The initial and final array index value is evaluated in runtime with help of the blocks LOWER_BOUND and UPPER_BOUND (Toolbox → Basic Instructions → Move Operations → array[*])

Requirements:

TIA V14.

Project:

Archived program, compressed (zip)