Siemens CPU 948 User Manual

Using floating point numbers Use floating point numbers for solving extensive calculations,
especially for multiplication and division or when you are working
with very large or very small numbers!
Accuracy The mantissa indicates the accuracy of the floating point number as
follows:
•• Accuracy with a 24-bit mantissa:
2
-24
= 0.000000059604 (corresponds to 7 decimal places)
If the sign of the mantissa is "0" the number is positive; if the sign is
"1" it is a negative number in its two’s complement representation.
The floating point value ’0’ is represented as the binary value
80000000H (32 bits, see below).
Coding floating point numbers Coding a floating point number:
31 30 24 23 22 0
V2
6
... . ... 2
0
V2
-1
.... . . . . . ... 2
-23
Exponent Mantissa
Specification of the data format for floating point numbers at the
PG: KG
Permissible numerical range
± 0.1469368 x 10
-38
to ± 0.1701412 x 10
39
Input/output on PG a) in a logic block:
You want to load the number N = 12.34567 as a floating point
number.
Input:
:LKG1234567+2
STEP 5 Programming Language
CPU 948 Programming Guide
2 - 10 C79000-G8576-C848-04

Siemens CPU 948 Specifications

General

Brand	Siemens
Model	CPU 948
Category	Controller
Language	English