CIF 3

Test station

../../_images/photo_test_station.jpg

Products coming from the input station can be delivered to the test station by means of the manipulator described for the input station.

The test station has to determine two different attributes of each product: the kind of material, and the thickness (or height). The main components of the test station are a pneumatic linear drive unit which acts as an elevator, and a conveyer belt used to transport qualified products towards the process station. Attached to the elevator platform is a pneumatic cylinder which is used to push the product off the platform.

The product to be tested is positioned at the location where three sensors are applied to determine the type of material. Each of the three sensors is different. The available sensors are: an capacitive sensor, an inductive sensor, and an optical sensor. Next, the elevator transports the product upwards to the measuring probe. Only products whose height is within the range of 24.0 to 26.0 mm are allowed to go through on the conveyer to the process station. The others must be rejected and removed from the flow line.

The conveyer belt has a (movable) sensor on it, that detects the presence of a product. This sensor may be located anywhere in the working area of the conveyer belt.

Sensors and actuators

This following table lists all the sensors of the workstation:

Index Label Type Initial state Event names Remark
0 SenConveyer Digital off ConveyerSensor.u_on, ConveyerSensor.u_off  
2 PushButton1 Digital off (released) Button1.u_pushed, Button1.u_released  
3 PushButton2 Digital off (released) Button2.u_pushed, Button2.u_released  
4 PushButton3 Digital off (released) Button3.u_pushed, Button3.u_released  
5 Switch Digital off Switch.u_on, Switch.u_off Bi-stable
6 EmergencyStop Digital on n/a NC contact
8 SenOptical Digital off OpticalSensor.u_on, OpticalSensor.u_off  
9 SenInductive Digital off InductiveSensor.u_on, InductiveSensor.u_off  
10 SenCapacitive Digital off CapacitiveSensor.u_on, CapacitiveSensor.u_off  
11 SenPusherIn Digital on PusherSensors.u_in_on, PusherSensors.u_in_off  
12 SenPusherOut Digital off PusherSensors.u_out_on, PusherSensors.u_out_off  
13 SenElevatorDown Digital on ElevatorSensors.u_down_on, ElevatorSensors.u_down_off  
14 SenElevatorUp Digital off ElevatorSensors.u_up_on, ElevatorSensors.u_up_off  
17 Thickness Analogue n/a ThicknessSensor.c_request, ThicknessSensor.u_low, ThicknessSensor.u_ok, ThicknessSensor.u_high  

This following table lists all the actuators of the workstation:

Index Label Type Initial state Event names
0 Pusher Digital off Pusher.c_on, Pusher.c_off
1 Conveyer Digital off Conveyer.c_on, Conveyer.c_off
2 ElevatorDown Digital on Elevator.c_down_on, Elevator.c_down_off
3 ElevatorUp Digital off Elevator.c_up_on, Elevator.c_up_off
4 Lamp1 Digital off Lamp1.c_on, Lamp1.c_off
5 Lamp2 Digital off Lamp2.c_on, Lamp2.c_off
6 Lamp3 Digital off Lamp3.c_on, Lamp3.c_off

Furthermore, multiple timers are available, as software implementations (virtual hardware):

Name Event names (mandatory) Event names (optional)
Timer1 Timer1.c_start, Timer1.u_timeout Timer1.c_cancel, Timer1.c_pause, Timer1.c_resume
Timer2 Timer2.c_start, Timer2.u_timeout Timer2.c_cancel, Timer2.c_pause, Timer2.c_resume
Timer3 Timer3.c_start, Timer3.u_timeout Timer3.c_cancel, Timer3.c_pause, Timer3.c_resume

For more information on timers, their mandatory and optional events, and how to model them, see the Timers page.

Simulation and visualization

The following is a screenshot of the visualization provided for this workstation, as part of the 4K420 course files:

../../_images/sshot_viz_test.png

The current simulation time is shown in the upper left corner. On the right, you’ll find the user interface. The buttons, lamps, and switch are all present. The product type detection sensors are also shown here. The buttons and switch can be turned on or off by clicking on them. Clicking once pushes the button or turns on the switch. Clicking once more releases the button or turns off the switch.

Clicking on one of the products, also on the right side, will add such a product to the system. The added products can be removed from the platform, by clicking on them. Removal of products from the platform by clicking on them, is only allowed when the platform is at the bottom (down position), and the pusher is in (retracted). The manual removal of products is useful, for instance when the supervisor prohibits the platform from going up for certain products. The rightmost product on the conveyer can also be manually removed, by clicking on it. Obviously, a supervisor may remove products also at different places.

The main part of the visualization shows the actual system, using a frontal view. Various sensors are visualized, as are the actuators (visualized as arrows).

Three timers are provided. There status is shown using rectangles. For more information on the visualization of timers, see the Timers page.

Configuration

The durations of the three timers that are provided, can be configured. That is, you can decide the durations of the each of the timers. To change the durations, open the config.cif file, and change the values of the appropriate constants. Make sure the read the comments that explain the allowed values. For more information on timers, see the Timers page.

If you change the configuration, the changes will automatically be applied to subsequent simulations, as well as for the next PLC code generation.

Similarly, you can configure the position of the sensor above the conveyer belt.