Week 4 2_basic_of_electro_hydraulics_design
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This document provides information on electro-hydraulic components including open/closed contact switches, relays, coils, solenoids, and logic circuits. It explains the symbols and functions of these components and how they are used in series and parallel circuits. Memory circuits are also discussed, along with examples of a memory on and memory off circuit. Relays are described as helping to switch small currents to larger ones and providing safety and interlocking capabilities. Solenoids function to switch valves on and off based on being energized or not.
Week 4 2_basic_of_electro_hydraulics_design
- 2. By the end of this lecture, student should be able to: ◦ Explain electro-hydraulic components symbol and function: series and parallel circuits, open/close contact switch, OR/AND logic circuit, relay, coil and solenoid ◦ Design and analyze memory circuit
- 3. 1. Open Contact Switch 2. Closed Contact Switch 3. Changeover Contact Switch – a combination of an Open and a Closed Contact Switch. Usually used on Relay and Limit Switch.
- 8. +24V 0V
- 10. IMPORTANT COMPONENTS IN ELECTRO-HYDRAULIC SYSTEMS RELAY SOLENOID
- 11. Consists of a coil and a set of changeover contact switch Its function includes: 1. To help switch over small current to larger current 2. To help switch over small voltage to larger voltage 3. Consists of multiple large contact switches for simultaneous switching of multiple outputs 4. Safety feature: Interlock capability
- 12. Coil Coil connections Contacts Contact connections Return spring Cover Symbol A1 A2 11 12 14 21 22 24 Armature
- 13. Symbol A1 A2 11 12 14 21 22 24 A1 A2 4 2 1
- 14. Symbol A1 A2 11 12 14 21 22 24 A1 A2 4 2 1
- 15. Symbol A1 A2 11 12 14 21 22 24 A1 A2 4 2 1
- 16. Symbol A1 A2 11 12 14 21 22 24 A1 A2 4 2 1
- 17. The circuit on the right is a direct connection without using relay. The lamp will switch on as soon as the contact switch is closed. However, if there is a power surge from the main, then the user will experience some form of electric shock. +24V 0V
- 18. The circuit on the right is an indirect connection with a relay (K1). Once the switch is pressed, relay coil (K1) will be energized. The coil will then closes the relay switch thus, switching the lamp. The safety measure here is that, if there is a power surge from the 240V, then the user will be protected from any form of electric shock. +24V 0V K1 K1 24 0V 2 different circuits
- 19. A solenoid is like a coil of the relay When it is energized, it will switch on the valve, similar to turning on the hand lever of a normal valve. If it is a single solenoid valve, then the valve will switch off automatically through a spring mounted at the opposite end of the valve. If it is a double solenoid valve, then the valve will switch off only after the second solenoid is being energized.
- 20. Single Solenoid Valve Double Solenoid Valve
- 21. Hydraulic Circuit Symbol Electrical Circuit Symbol A B P T Y1 Y2 A B P T Y1 Y1 Y1 Y2
- 22. F=0 A B P T Y1 Y2 +24V 0V S1 K1 K1 Y1 S2 K2 K2 Y2
- 23. Relevancy: 1. Used to build Continuous Cycle circuit. 2. Used to latch a circuit for continuous supply of electricity to a particular line. 3. Used when replacing a double solenoid valve to a single solenoid valve of a circuit, without changing the originality of the circuit function.
- 24. Memory ON (Dominant Set) +24V 0V ON K1 K1 OFF K1 • When ON is pressed, Relay coil K1 will be energized. Both relay K1 switches will close. This means, while the lamp turns on, the relay switch will continuously energize the coil. Therefore, the lamp is permanently on. Only when the OFF button is pressed, the lamp will switch off. • To confirm that this is a Memory ON circuit, press both ON and OFF together. The lamp will still light ON.
- 25. Memory OFF (Dominant Reset) • The function of this circuit is similar to the previous Memory ON circuit. However, please note that the OFF button is placed below the ON button, not parallel! • To confirm that this is a Memory OFF circuit, press both ON and OFF together. The lamp will NOT light ON. +24V 0V ON K1 K1 OFF K1
- 26. Proximity -> closeness Detect close objects without contact. Various types: 1. Inductive sensor 2. Capacitive sensor 3. Optical sensor
- 27. Used to sense only metal type of object.
- 28. Used to sense only high density objects.
- 29. Used to sense only reflective type of object.