Designing a Sequential Control System based on the Example of a Drill
S7-GRAPH for S7 300/400 Programming Sequential Control Systems
3-12
C79000-G7076-C526-01
3.7
Programming Step Actions
There are also two methods available for programming step actions and
transitions: Direct and Drag & Drop. The procedure described below assumes you
have selected the menu command Insert > Drag & Drop:
1. Select the menu command Insert > Action.
Result: The mouse pointer then appears as shown below:
2. Insert an empty action line by clicking the action box.
3. Enter the actions.
An action consists of an instruction and an address. For the drill program, four
different instructions are necessary in the steps:
•
S
Set
output
•
R
Reset
output
•
N
Non holding: As long as the step is active, the signal state of the
address is 1.
•
D
Delay: The address is set to 1 after the defined time has elapsed
following activation of the step and is reset when the step is
deactivated.
3.8 Programming
Transitions
The bit logic instructions "normally open contact", "normally closed contact" and
"comparator" are used for the step enabling conditions in the transitions. To
program transitions:
1. Set the "LAD" view and select the relevant buttons in the "LAD/FBD" toolbar
Insert normally open contact
Insert normally closed contact
Insert comparator
2. Position the symbols at the appropriate points by clicking the transition lines.
You can exit the insert mode at any time with the ESC key.
3. Enter the addresses. Click the placeholder "??.?" of the required text field. Then
enter an absolute or symbolic address (for example I 0.7, "Start_switch").