The CASCADE Method similar to that for electromechanical devices. involves dividing the sequence into groups with each group’s manifold (power or main pressure line) being supplied with pneumatic power (pressure) one at a time and in sequence. Motion within each group is powered by its own group manifold.

The CASCADE Method – Step 1 Divide the sequence into Groups so that no letter is repeated within any Group. Example: START, A+, B+, B-, A-, C+, C- I II I

Step 2: For each cylinder, assign a 4/2(or 5/2) control valve with double pilot lines (i.e., without spring return) and two spring-return 3/2 limit valves to indicate end of strokes. START, A+, B+, B-, A-, C+, C- I II I Example

Step 3: Assign one or more Group Valves or Cascade Valves to control air pressure to the Group manifold lines so that only one Group manifold line is pressurised at any one time and in sequence. Examples of Cascade Valves for 2, 3 and 4 groups. I, II, III and IV are outputs to Manifolds. 1,2,3 and 4 are input control lines to switch to their respective groups. II I

Step 3: Assign one or more Group Valves or Cascade Valves to control air pressure to the Group manifold lines so that only one Group manifold line is pressurised at any one time and in sequence. START, A+ B+ B- A- C+ C- I II I Example

Step 4 There are two approaches. Approach 1: Design according to the sequence and using your understanding of how the Cascade Method is intended to work. The principal basis is the switching of the Group manifolds. Approach 2: Design according to a set of rules worked out according to the principles of the Cascade Method.

Begin with START. Input to START comes from c- limit valve and output goes to initiate A+ motion. After A+ motion, take input to a+ from its own Group I manifold and output to initiate B+ motion. Approach 1 START A+ B+ B- A- C+ C- I II I Example

At the end of the B+ motion, limit valve b+ is actuated At the end of the B+ motion, limit valve b+ is actuated. Connect its input to its own Group I manifold and take the output signal to switch to Group II. Approach 1 START A+ B+ B- A- C+ C- I II I Example

We’re in Group II now. First action is B- We’re in Group II now. First action is B-. Connect Group II manifold to initiate B- motion. At the end of B- stroke, connect input of b- to its own Group II and output to initiate A- motion. Approach 1 START A+ B+ B- A- C+ C- I II I Example

At end of A- stroke, a- limit valve is actuated At end of A- stroke, a- limit valve is actuated. It then take Group II power, connected to its input, and its output initiates C+ motion. At end of C+ stroke, need to use c+ to switch to Group I. Approach 1 START A+ B+ B- A- C+ C- I II I Example

We’re now into Group I. First action is C- We’re now into Group I. First action is C-. Thus, connect Group I manifold to initiate C- motion. At end of C- stroke, c- takes its input from Group I and output its signal to the next action, which is START.  Approach 1 START A+ B+ B- A- C+ C- I II I Example

Approach 2 Step 4 Connect the input of the limit valve at each stroke extremity to its own Group manifold… START, A+, B+, B-, A-, C+, C- I II I Example

Step 5 For the first letter in each Group, connect the corresponding control valve input to its own Group manifold … START, A+, B+, B-, A-, C+, C- I II I Example

Step 6 For the last letter in each Group, connect the output of the corresponding limit valve to switch to the next Group … START, A+, B+, B-, A-, C+, C- I II I Example

Step 7 For all other letters, connect the output of the corresponding limit valve to the control valve input corresponding to the next letter in the sequence START, A+, B+, B-, A-, C+, C- I II I Example

Step 8 Incorporate a 3/2 spring-returned manually-operated START valve Step 8 Incorporate a 3/2 spring-returned manually-operated START valve. The circuit should now be complete START, A+, B+, B-, A-, C+, C- I II I Example

Taking care of Repeated Motions START, A+, A-, A+, A- Cylinders requiring repeated motions will need "OR" logic at the control valve.

Taking care of Repeated Motions START, A+, A-, A+, A- For each motion, there needs to be an associated limit valve to detect end of motion.

Another example: START, A+, A-, A+, A- IV I II III IV Because of repeated motion, more than one limit valves are required for each stroke extremities, one for each motion. The bottom figure is an alternative. Shuttle valves are used for the OR logic function.

Another example: START, A+, A-, A+, A- IV I II III IV Assign the Cascade Valves for 4 groups making sure that the connections are drawn such that Group 4 Manifold is pressurized since START is in Group 4. Draw in the four Group Manifold lines.

Another example: START, A+, A-, A+, A- IV I II III IV For the first letters in each group, connect the relevant input of the cylinder control valve to its own group manifold. For this example, all the four letters are first letters.

Another example: START, A+, A-, A+, A- IV I II III IV According to Step 4, connect all the inputs of all limit valves to their own group manifold lines. Connect the input of the START push-button to the output of the previous action, in this case, the output of limit valve corresponding to the 2nd A- motion.

Another example: START, A+, A-, A+, A- IV I II III IV The two A+s, the first A-, and START are all last actions in their respective groups. Connect the outputs of the corresponding limit valves, and of START, to switch to the next group. In the case of START, this is to switch to Group I. The circuit now should be complete.

End of Cascade Method