[?]: Display number of digital inputs

[Frz 1995]

In the step 7 s300 (with fbd or ladder) write a program that display number of true digital inputs of a card with 16 inputs in every moment.

[MaxS]

Henry S. Warren, Jr. - Hacker’s Delight (Second Edition)
Chapter 5. Counting Bits

For 16 bits:

Code: Select all

  x = (x & 0x5555) + ((x>>1) & 0x5555);
  x = (x & 0x3333) + ((x>>2) & 0x3333);
  x = (x & 0x0F0F) + ((x>>4) & 0x0F0F);
  x = (x & 0x00FF) + ((x>>8) & 0x00FF);
  return x;

SIMATIC Step 7 (FBD)

Show