Industrial Electronics DAE 32003 Industrial Electronics Jabatan Kejuruteraan Elektrik, PPD

HYDRAULIC AND PNEUMATIC CONTROL SYSTEM CHAPTER 7 HYDRAULIC AND PNEUMATIC CONTROL SYSTEM

Introduction to Pneumatic systems Pneumatic products represent a multi-billion dollar industry today. Pneumatic devices are used in many industrial applications. Most pneumatic devices are designed to use clean dry air as an energy source. The actuator then converts that compressed air into mechanical motion. The type of motion produced depends on the design of the actuator.

Introduction to Pneumatic systems Electro pneumatic system consist of both electrical and pneumatic system. Usage of electro pneumatic includes: Packaging Stamping, shearing & embossing part Sorting part Component stacking Material stacking

Introduction to Pneumatic systems Example of Pneumatic Diagram

Introduction to Pneumatic systems Example of Electrical Diagram

System components Solenoid valve Cylinder Compressor Actuator

System components

System components: SOLENOID VALVE Solenoid valve symbols

System components: DIRECTIONAL CONTROL VALVE Directional control valve is attached with solenoid, so that it can move forward & backward. The movement of the valve allows compressed air to go into the airway of the valve to control the movement of the cylinder.

System components: DIRECTIONAL CONTROL VALVE POSITIONS (Y) [ X / Y ] WAY VALVE PORTS (X) For this EXAMPLE: X = 4 ; Y = 2 4 / 2 WAY VALVE

System components: DIRECTIONAL CONTROL VALVE Valve switching positions are represented by squares. The number of switching positions of the valve is shown by the number of squares. The arrow show the direction of flow paths. Shut off positions are identified in the boxes by lines at right angles. The connection (inlet and outlet ports) are shown by lines on the outside of the box and are drawn in the initial position.

System components: DIRECTIONAL CONTROL VALVE Port or connection DIN ISO 5599 Lettering System Pressure port 1 P Exhaust port 3 R Exhaust ports 5,3 R,S Signal outputs 2,4 B,A

System components: DIRECTIONAL CONTROL VALVE

System components: CYLINDER Single acting cylinder SV DE-ENERGIZE Rest position, air supply shut off, cylinder retracted by the spring. When switch closed, current flow to the circuit & start to energize solenoid coil. Magnetic field created, push the plunger that will slide the valve to the right.

System components: CYLINDER Single acting cylinder This will allow the air to flow inside the piston & extend the piston. If switch released, the valve will slide back & cause the air to stop. SV ENERGIZE

System components: CYLINDER Double acting cylinder Rest position, air supply flowing to the cylinder piston rod via the valve and pushing the piston at rest / retraction position - no current flow to the solenoid Switch closed, energized solenoid coil-magnetic field develop at solenoid. SV DE-ENERGIZE

System components: CYLINDER Double acting cylinder Magnetic filed develop push the plunger and cause valve slide to the right. This allow air flow inside the piston via the other port & push/extend the valve. When switch released, current not flow, cause the magnetic field weaker and vanish - valve slide to initial position. SV ENERGIZE

System components: CYLINDER Single acting cylinder Double acting cylinder

System components: DIRECTIONAL CONTROL VALVE

System components: DIRECTIONAL CONTROL VALVE

System components: CYLINDER

Hydraulic systems

Control of pneumatic systems using PLC

Control of pneumatic systems using PLC Another consideration is important for double solenoid valves. Most double solenoid valves cannot withstand simultaneous activation of both coils. One of the circuits shown in Figure LC-8 should be considered to prevent this occurrence. In both circuits, SOL-A and SOL-B are attached to the same solenoid valve. A single control relay (CR-1) is used in the left circuit to activate contacts (CR-1A and CR-1B) which cannot be closed simultaneously. The circuit on the right uses the same principle for each solenoid coil.