Sample problems for the Model # MVF-1 electro-pneumatic trainer
"It is very evident that along with studying and working with pneumatics, students are developing their problem solving skills by using logic.
They must go from the written description to a schematic drawing then to the final step of setting up and see if  the circuit operates as specified."
Problem 7

Control Air Cylinder with single solenoid valve

Initial Conditions

  1. Control power On

  2. Power air on

  3. Cylinder retracted

  4. Ready to start

Sequence of Control Operations

  1. Operator momentarily presses push button PB1

    • Cylinder extends

  2. Operator momentarily presses push button PB2, cycle reset button

    • Cylinder retracts

  3. Cycle complete

Solutions to be developed by the students
Click on images to expand
Left hand image shows physical components. Right hand image shows the ladder logic diagram.

Problem 24

Clamp, Drill 1, Drill 2 Control Circuit

Initial Conditions

  1. Power air on

  2. Control power On

  3. All Cylinders retracted

  4. Ready to start

Sequence of Control Operations

  1. Operator momentarily presses cycle start button PB1

    • Clamp cylinder starts to extend

  2. As clamp cylinder starts to extend, limit LS3 is released

    • No Action

  3. When clamp cylinder is fully extended, it makes LS4

    • Drill cylinder 1 starts to extend

  4. As Drill cylinder 1 starts to extend, it opens RS1

    • No action

  5. When cylinder 1 is fully extended, it closes RS2

    • Drill cylinder 2 starts to extend

  6. As drill cylinder 2 extends, it releases LS1

    • No action

  7. When drill cylinder 2 is fully extended, it makes LS2

    • CR2 is energized

  8. When CR2 is energized, Drill cylinders 1 and 2 begin to retract

    • No action

  9. As the drill cylinders retract, Drill cylinder 1 opens RS2, and cylinder 2 releases LS2

    • No action

  10. When drill cylinder 1 is fully retracted, it closes RS1

    • No action

  11. When drill cylinder 2 is fully retracted, it makes LS1

    • Clamp cylinder begins to retract

  12. As clamp cylinder begins to retract, it releases LS4

    • No action

  13. When clamp cylinder is fully retracted, it makes LS3

    • System is reset for next cycle

  14. End of cycle

Statement of Safety: If control power is lost, Drill 1 and 2 will retract and clamp will remain in clamped position. Upon obtaining control power, no cylinder will move without depressing PB1 and drill cylinders will ten resume from the beginning of the cycle.

Left hand image shows physical components. Right hand image shows the ladder logic diagram.