Task: Logic-based control

Use FluidSim to solve the following tasks. Please solve one task during the practical session. Select the station which you have not worked on before.

Conveyor belt

Workpieces are transported in every automated assembly. In the MecLab, a conveyor belt is provided for this purpose. The conveyor belt should not run continuously in order to save energy. Therefore, the conveyor belt should always switch on when a workpiece is placed at the start of the belt and stop when the transport task has been completed. The workpieces can be of any color.

Todo

How can it be achieved that the belt only runs when a workpiece is in contact?

Todo

Which logic component can be used to ensure that the motor runs as long as the workpiece is transported to the end of the conveyor?

Todo

Implement the belt functionality in FluidSim using a simulated motor and logic elements in the digital module.

Conveying and sorting tasks are important functions in any production. The task is to design a conveyor belt and an associated control program that has the following characteristics: Workpieces (black cans) are to be transported from the beginning of the belt to the end of the belt. The transport should start when a workpiece is placed at the beginning of the belt and stop after the workpiece has left the belt at the other end. Silver workpieces are to be sorted out onto the chute.

Todo

Expand the simulation of the conveyor belt which fulfills the described functionalities. Add an ON/OFF switch or the whole system. The functionality should be implemented using logic elements in the digital module.

Now, the system works in simulation mode. Thus, the next step is to test everything in real life.

Todo

Check the pin assignment at the distributor (“Multipolverteiler”).

Todo

Control the real conveyor belt via FluidSim.

Todo

What happens if you first place a silver can and shortly afterwards another silver can (distance approx. 3 cm) on the conveyor belt? Is it sorted out correctly?

If not, extend or change the logic diagram in the digital module to achieve more precise sorting. Also test other combinations.

Stack magazine

An important function of the stacking magazine station is the pressing of can and lid. A control system is to be designed for this purpose.

A vertically arranged pneumatic cylinder is to be used for pressing in, which is supplied with air by a solenoid valve and controlled by the PC. The cylinder is to extend at the push of a button and remain extended as long as the button remains pressed. An important boundary condition is that, for safety reasons, the cylinder also returns to the upper end position in the event of a power failure.

Todo

Create a simulation of both cylinders in which the magnetic valves are controlled by buttons. The single-acting cylinder should be operated by one button, the double-acting cyclinder by two buttons. Use flow control valves to adjust the operation speed.

Sensors are important components of any automated system. In the stacking magazine station, there is a magnetic limit switch which detects the position of the cylinder piston.

A control system for the stacking magazine is to be developed with the following features:

  • The operator places a can in the assembly fixture and presses the start button.

  • The double-acting cylinder pushes a lid out of the magazine tower (onto the can) and then moves back to the starting position.

  • The single-acting cylinder presses the lid into the can for exactly 10 seconds.

  • The operator removes the finished workpiece (lid plus can).

  • The can and lid may be of any color.

Todo

Modify the circuit from the previous task so that the solenoid valves are controlled by the digital module instead of by pushbuttons. Add a start button and the magnetic limit switch of the double-acting cylinder and connect them to the inputs of the digital module.

Todo

Create the circuit for the plant in the digital module using logic elements. Test the control in the simulation. Add an ON/OFF switch for the whole system.

Todo

Check the pin assignment at the distributor (“Multipolverteiler”).

Todo

Control the real stack magazine belt via FluidSim.

Todo

What happens,

  1. if you press the start button again during the pressing process?

  2. if you press the start button permanently?

Could this cause problems with the operation of the station? If so, extend your logic diagram to avoid this. Test again with the help of the simulation.