S5 square root function

Use Newton's method, as described in any text on Numerical Methods. It converges rapidly.

TIP: For an initial approximation, use a non-zero value that has half has many bits as the number of which you're trying to find the square root.


Michael Griffin

Siemens has (or had) a set of standard numerical function blocks for use with the S5 PLCs. You may wish to check if this product has a square root
function block.

Michael Griffin
London, Ont. Canada
Dear fids,

The 100U, 115U, 135U processors use standard function block F5 as a "16 bit binary root extractor". This is FB18 in the 150U and 155Us.

I don't have current information on the 90U and 95U but they likely use the FB5 as well.

Let me know if I can be of additional help.

Thanks. Joe
Joseph Luft
FasTrak SoftWorkS, Inc.
[email protected]