Description of tasks

Your employer has decided to automate the riveting process in the production. In the

riveting two pieces of metal are connected together by steel rivets. The mechanical

departement of the company has planned and build a prototype of riveting machine.

Your goal is to plan and automate the pneumatic and electric control of the machine according to

the safety regulations.

The device has three pneumatic acting actuators.

3

1 2

1) Fastener

-Single acting cylinder, which keeps the riveted component in place

-Cylinder has no limit switches, only pressure switch , which controls correct

working pressure.

-Control of the cylinder is made by pneumatically operated 3/2 way valve.

2) Support cylinder

- When the component is secured in its place by fastener cylinder, double acting support

cylinder moves forward and supports the component during the riveting.

-Cylinder has two mechanical micro limit switches to control the forward and backward

positions of the piston.

-Control of the cylinder is made by electrically operated 5/2 way valve with

two solenoids.

3) Riveting cylinder

- Double acting cylinder has two reed proximity switches to control the forward and

backward positions of the piston.

-When component is secured in its place and the support cylinder is in the forward position,

this riveting cylinder makes four strokes.

-Control of the cylinder is made by solenoid operated 5/2 way valve with spring return.

The first task is to design, document, and connect the fastener cylinders peumatic control circuit.

For safety reasons, the control of the fastener shall be a pneumatic two-hand control.

-Fastener cylinder moves forward when two manually controlled pneumatic valves are pressed

simultaneously.

-Cylinder returns in its original position if one or the other of the manually controlled valves is

released.

-Cylinders speed of the movement is controlled by one way flow control valve. Adjust the speed of

movement so that the time from backward to forward position is 3 seconds.

Task 1:Fulfill the pneumatic control circuit below by given symbols. Simulate the circuit by

fluidsim. Then make the real connections to the pneumatic board and test it. Working pressure is

4,2 bar.

Task 2: Next we will add solenoid valve and auxiliary relays to the fasteners control circuit. This is

done by adding solenoid valve, pressure switch , relays and suitable push button.

-Next to the cylinders air connection is added pressure switch P1 which triggers when a

suitable working pressure is reached. Connect the signal wire to normally closed (NO)

contact of the pressure switch. Triggerin pressure is 4.0 bar.

Pressure switch controls relay K1. Make a hold circuit to the relay. Relay controls

solenoid Y1 so that fastener cylinder leaves forward position when the suitable working

pressure is reached.

Connect pushbutton S1 to the circuit by which the hold circuit could be released.

Fullfill next pneumatic and electric circuits with given symbols. Test these circuits with

fluidsim. Then make the real connections to the pneumatic board.

Fullfill the electric control circuit and missing component identification marks.

Task 3 : PLC control of riveting machine. (Programming part of this task is optional,

if you are not familiar with codesys enviroment you can also use demo program in the monitor

mode).

Program the sequence according to the description below using codesys programming

platform.

Sequence:

-Attach the component using pneumatic two-hand control valves.

-When the working pressure is ok., pressure switch triggers and hold

circuit keeps the fastener cylinder in the front position.

-Indicator light H1 lights up.

-You are now able to start the automatic drive by pressing start button S2.

-When you press the start button indicator light H2 lights up and automatic

sequence starts:

-support cylinder moves front position.

-when the support cylinder is in its front position riveting cylinder

makes 4 front and back moves.

-when the riveting cylinder has made 4 moves and has come

to the back position , support cylinder moves back.

-when the support cylinder is in the back position incator ligth

H2 goes off and the sequence ends.

-New sequence starts by pressing S2

Other rules:

-Automatic drive is possible only when fastener cylinder is ready

-H1 lights up only when working pressure is at the right level.

-H2 lights only during the automatic sequence.

-If the working pressure of fastener cylinder goes down during automatic sequence,

all cylinders returns at their starting positions and the sequence stops.

Make the pneumatic connections of the cylinders according to the pneumatic diagrams below to the

pneumatic board.

Connect electric control circuit of the plc according to the input and output diagrams.

Push buttons and indicator lights you can find from the festo module descriped below.

Input diagram:

:

Output diagram