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?