Periodic Sequence Control

A simple example where periodic sequence operation of machineries is applied is shown in figures below (A). At first, a solenoid valve G1 opens to let the flow of the liquid ingredient I, from tank T to container N. A calculated pre-set time is allowed to fill the container N at sufficient level poured ingredient. After the pre-set time hase elapsed, the solenoid valve G1 is closed to stop the pouring ingredient 1.

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Immediately after the solenoid valve G1 is closed, the motor M starts to operate and mix the poured ingredients in container N. Sufficient time is allowed to the mixing process and after which the motor M is de-energized to stop the mixing.

Right after the mixing stop, another solenoid valve G2 will open to drain the mixed ingredient in container N. When container N is fully drained, the solenoid valve G2 will close.After the closing of solenoid valve G2, the solenoid valve G1 will open again and the process is repeated.

(A) Illustrate a simple process where periodic operation of machineries is applied.

 

CONTROL OPERATION

Referring to figure below (A1) and (B1), pressing the start push button will energize contactor C1, timer TR1, and indicating pilot lamp A. Contact C1 (13-14) will close to maintain contactor C1, timer TR1, and indicating pilot lamp A energized. Contact C1 (11-12) will open. Also contact C1 (1-2,3-4,5-6) will close to energize and open gate valve G1. This is the operation for pouring process.

After a pre-set time normally open delay contact TR1 (6-8) will close energize contactor C2, timer TR1, and indicating pilot lamp B. Contact C2 (11-12) will open to de-energize contactor C1, timer TR1, and indicating pilot lamp A to bring about the closing of gate valve G1 and stop the pouring process. Also, contacts C2 (1-2,3-4,5-6) will close to energize motor M.  This is the operation for the mixing process.

(A1)   Periodic Sequence Control Circuit

After sufficient time is allowed for the mixing process, the normally open-delayed contact TR2(6-8)will close to energize contactor C3, timer TR3, and the indicating pilot lamp C. Contact C3(11-12) will open to de-energized contactor C2, timer TR2, and indicating pilot lamp B. The mixing process will stop. Also, contacts C3(1-2, 3-4, 5-6) will close to energize and open the gate valve G2. This is the operation for the draining process.

(B1)  Periodic Sequence Control  Power Circuit

A sufficient time, pre-set by TR3, is allowed to drain the mixed ingredients from the container N. After the pre-set of TR3 has elapsed, contact TR3(8-6) will close to energize contactor C1, timer TR1, and the indicating pilot lamp A again. Contact C1(11-12) will open to de-energize C3, timer TR3, and indicating pilot lamp C. This will stop the draining process. Since C1 is energized again, the pouring process is repeated.

The pouring, mixing, and draining is repeated periodically until the stop push button is pressed.

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