Siemens SIMATIC S5-100U, System Manual

Page: 212 / 552

STEP 5 Operations S5-100U
8.2.9 “DO” Operation, for CPU 103 and Higher
Use the “DO” operation to process STEP 5 statements as indexed operations. This allows you to
change the parameter of an operand during control program processing (see Table 8-19).
Table 8-19. Overview of the “DO” Operation
Operation Meaning
Parameter
0 to 254
0 to 255
Operand
DO Processing a flag word or data word
ID
FW
DW
“DO” Statements
“DO flag word or data word x” is a two-word statement that is unaffected by the RLO. “DO”
consists of the following two statements:
• The first statement contains the “DO” operation and a flag word or data word.
• The second statement defines the operation and the operand identifier you want the control
program to process. You must enter 0 or 0.0 as the parameter.
The control program works with the parameter that is stored in the flag word or data word. This
parameter is the one called up in the first statement. If you want to index binary operations, inputs,
outputs, or flags, you input the bit address in the high byte of this word. You input the byte address
in the low byte. In any other instance, the high byte must be “0”.
You can combine the following operations with the “DO” statement:
Explanations Operations
1 In combination with “DO FW,” the “A I” operation becomes the “A Q” operation if the byte address in
the data word or flag word is higher than 127.
A
1
, AN, O, ON
S, R, =
FR T, RT, SF T, SD T, SP T, SS T, SE T,
FR C, RC, SC, CD C, CU C
L, LD, T
JU=, JC=JZ=, JN=, JP=, JM=, JO=
SLW, SRW
D, I
C DB, JU, JC, TNB
Boolean logic operations
Set/reset operations
Timer operations
Counter operations
Load and transfer operations
Jump operations
Shift operations
Decrement and increment
Block calls
!
Caution
Damage to the system.
Performing operations that are not listed in Table 8-20 will damage your system.
Perform only those operations that are listed in Table 8-20.
8-54
EWA 4NEB 812 6120-02b