Data Blocks - Siemens S5-100U User Manual

Introduction to STEP 5
PB 3
: JU FB5
NAME : EXAMPLE
X1 : I 0.0
X2 : F 1.3
X3 : Q 1.0
.
.
: A I 0.1
: JC FB5
NAME : EXAMPLE
X1 : I 0.3
X2 : I 0.2
X3 : Q 1.0
7.3.5

Data Blocks

Data blocks (DB) store data to be processed in a program.
The following data types are permissible:
• Bit pattern (representation of controlled system states)
• Hexadecimal, binary or decimal numbers (times, results of arithmetic operations)
• Alphanumeric characters (ASCII message texts)
7-16
Parameter list
for first call
Actual operands
Parameter list
for second call
Formal operands
Figure 7-6. Programming a Function Block
FB 5
NAME : EXAMPLE
DES: X1 I BI
DES: X2 I BI
DES: X3 Q BI
: A = X1
: A = X2
: = = X3
: BE
Formal operands
S5-100U
Executed
program
First call
A I 0.0
A F 1.3
= Q 1.0
Second call
A I 0.3
A I 0.2
= Q 1.0
EWA 4NEB 812 6120-02