1.     Manually placing the keytag on the loading nest.
     2.      Manually driving the shaft that actuates the four-bar mechanism to load the key tag on to the
              rotational nest.       
     3.     Manually lowering the shaft that turns the keytag.
     4.     Old PLC controlled the router operation.
     5.     Manually raise the shaft that turns the keytag.

The new PLC controlled fixture will perform the following operations:

     1.     Manually placing the keytag on the loading nest.
     2.     Press start button
     3.     Suction is enabled for the coupler link of the 4-bar mechanism
     4.     Key-tag is picked up by the coupler
     5.     Key-tag is set down onto the rotational nest
     6.     Suction is turned of, 4-bar returns to home, and limit switch contacts made
     7.     Shaft is actuated down.
     8.     Router turns on, motor to rotational nest turns on.
     9.     After 360 degree’s of rotation another limit switch is thrown and step 8    turn

2. Design Considerations
A few components of the fixture had to be redesigned.  Essentially one more 12 V motor had to be added to the fixture to control the actuation of the four-bar mechanism.  A two-way air cylinder and a solenoid valve were then added to raise and lower the shaft that spins the keytag.

3.  PLC Design
The previous fixture operated via an Allen-Bradely SLC 150.  Due to the number of ouputs required and the potential integration of the fixture to the keytag assembly, it was decided to use the PLC-5 over the existing SLC 150.  By using the PLC-5, the student would be able to simultaneously run the round-off machine with the keytag machine.

4.  Electical Schematic
The following electrical schematic shows the inputs/outputs to and from the system using the Allen-Bradley PLC-5:

5.  Ladder Logic
The following ladder logic was used to program the PLC-5.




 

6.  Images of Key Tag Round Off Machine