Instruction for Experiment
Programowanie sterownika PLC S7-200
1. Aims
The aims of the experiment is to make students familiar with the following topics:
" Programming of PLC S7-200,
" Rules of drawing pneumatic schema.
2. Equipment
Software:
" Step 7 MicroWIN,
Hardware:
" Personal computer,
" Programmable logic controllers S7-200 family  see exemplary picture presented in
Fig.1.,
Fig. 1. Exemplary Simatic S7-200 PLC
" PC/PPI communication cable and interface  see Fig.2,
Fig. 2. PC/PPI cable and interface
" Pneumatic components: single acting pneumatic actuators (Fig.3), double acting
pneumatic actuators (Fig.4), two single acting electrically controlled pneumatic valves
(Fig.5. and Fig.6.), pneumatic pipes, air compressor.
Fig. 3. Exemplary single acting pneumatic actuator
Fig. 4. Exemplary double acting pneumatic actuator
Fig. 5. Single acting, electrically controlled pneumatic valve
Fig. 6. Single acting, 5 ways electrically controlled pneumatic valve
" Two inductive sensors detected all kind of metals
Fig. 6. Inductive sensor
3. Program of experiment
" Making the connection between PLC and PC,
" Making the connection between pneumatic components,
" Connecting the electropneumatic valve into PLC,
" Writing the program in PLC which allows to control pneumatic actuators.
4. PLC and PC connection
Connection between PLC and personal computer should be done with help of PC/PPI
interface. One plug of PC/PPI cable should be connected into RS485 connector in PLC  see
Fig.5. Second plug of PC/PPI cable should be connected into PC RS232 interface.
5. Making the connection between pneumatics components
Pneumatic components should be connected according to following schema:
Fig. 7. Schema of connection between pneumatic components
After connection check correctness (be shore if laboratory set is pressurized) of working by
pressing manual switch on electropneumatic vale. After switch pressing pneumatic actuator
should pull out the cylinder. When the switch will be released the actuator should pull out the
cylinder into initial position (starting position). Where you may find the manual switch on
electropneumatic valve you may see in Fig.8.
Fig. 8. Top view of electropneumatic valve
6. Connecting PLC, pneumatic valves and sensors
The control terminals of electropneumatic valve should be connected into output terminals of
PLC. Fig.9 presents position of output terminals of PLC where may be connected
electropneumatic valve and additional voltage source, while signals from sensors should be
connected into inputs terminal of PLC.
Fig. 9. Output terminals  1L and  2L of PLC
Electric components should be connected according to following schema:
Fig. 10. Schema of connection between pneumatic components
Table 1. Inputs  limit switch table
Input number Limit switch Comments
I0.0 S0 single acting actuator pull out
I0.1 S1 double acting actuator pull out
Table 2. Outputs table
Output number Comments
Q0.0 single acting actuator moving forward
Q0.1 double acting actuator moving forward
7. Work with software and exemplary program written on PLC
After connecting electric and pneumatic circuits, we may open STEP 7 MicroWin. First we
have to open new project and choose programming language (View Stl, Ladder or FBD).
On Fig. 11. shows view of main window.
Fig. 11. Step 7 MicroWin view of main window
After choosing programming language we may create program, example program is showing
on Fig. 12.
Fig. 12. Example program
How this exemplary program works??
After switch on pressure pneumatic actuators should be in homeposition and both sensors are
inactive, next we set output Q0.0, it means that single acting actuator is moving forward.
When single acting actuator is pull out, first sensor is active (I0.0), so we set Q0.1. Afterwards
pull out double acting actuator (both sensors active), single acting actuator is coming to
homeposition and next double acting actuator is coming to homeposition too.
When program is done, and PLC is connected with PC, we can download program by
choosing or (File Download). On picture below shows view of  download window
Fig. 13.  Download window
8. Report
Report should include:
" Schema of pneumatic and electric connections,
" Written program controlling motion of pneumatic actuator,
" Description haw program works
References
[1] www.siemens.com
Questions
1. How on schema are presented pneumatic components like: double acting actuator and
different valves?
2. How to connect PC and PLC and exchanging the data between them?
3. How to implement the logic  AND with help of relays in ladder logic diagram?