Do" Operation - Siemens SIMATIC S5 Manual

S5-115F Manual
3.2.9

"DO" Operation

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 3-19).
Operation Operand
DO
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.
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".
The following operations can be combined with the "DO" statement:
L FY, T FY, L FW, T FW, L IB, T IB, L QB, T QB, L IW,
T IW, L QW, T QW, L DL, T DL, L DR, T DR, L DW, T DW
CDB, JU OB, JU SB, JU FB, JU PB, JC OB, JC SB, JC FB,
JC PB
A F, = F, A T, AN T
S F, R F, R T
SS T, SE T
SLW, SRW
Warning
!
Operations other than that listed in the above table are not permissible and will be
rejected by the operating system.
EWA 4NEB 811 6149-02
Table 3-19. Overview of the "DO" Operation
Processing a flag word or data word
Parameter
0 to 254
0 to 255
Operations
Meaning
If you want to index binary operations,
Explanations
Load and transfer operations
Block call operations (FBs must
have no formal parameters)
Boolean logic operations
Set/reset operations
Timer operations
Shift operations
STEP 5 Operations
3-55