INTRODUCTION TO ELECTROPNEUMATICS

INTRODUCTION TO ELECTROPNEUMATICS

Introduction:-

Integration of pneumatic and electrical technologies has played an important part in the development of a large range of industrial automation solutions. More than ever, the need for cost effective and efficient production systems demands that machine cycle times are minimized. An electro pneumatic control offers a number of advantages to the developer of control systems .Where signals are transmitted over great distances in a control system, the time between signal transmission and signal reception is minimized using electricity as the transmission medium.

Where growth in production is anticipated, the incorporation of solenoid actuated valves also provides the developer with the option of developing the system to incorporate controller that allows the system operating cycle to be altered as production requirements change.

1.1 Electro pneumatics control an overview:-

 Electrical components used in the system basically have the following roles.

1. Sensing information.
2. Processing information.

The sensing of information can be carried out by roller actuated limit switches, magnetically actuated switches or electronic sensors that sense whether or not a particular operation has occurred. This information is passed to the processing device, which may be a relay. The processor then has the task of directing and modifying its received signal to drive the output stage of the system. This output stage generally has two parts .Firstly a final control element that is electrically actuated with a pneumatic output and secondly the pneumatic actuator

General applications for electro pneumatic systems include:-

1. Packaging
2. Feeding
3. Metering
4. Door and hopper control
5. Material transfer
6. Sorting of parts
7. Component stacking
8. Stamping, shearing and embossing parts etc 

1.2 System structure and signal flow:-

Components in a control system can be identified as belonging to four basic groups .The primary levels of an electro pneumatic system structure are

1. Energy supply (Compressed air and electrical)
2. Input elements (Limit switches/push buttons/proximity sensors)
3. Processing elements(Switching logic, solenoid valves, pneumatic to electric converters)
4. Actuators and final control elements(cylinders,motors,directional control valves)

Components in the system are represented by symbols which indicate their function. The symbols are then combined to represent a solution for a particular control task and this representation forms the circuit diagram

The following figure shows a typical component placement of a electro pneumatic control system                                                                                       

                                                                Pneumatic +24V   Electrical   

Electro pneumatic components:-

       Electro pneumatic components fall under the following category

• Actuators:-

Pneumatic cylinders, Rotary actuators, Lamps /Buzzers.

• Control ElementsSolenoid actuated directional control valves, Relays.

• Processors:-

Solenoid actuated directional control valves, Logic elements, Pneumatic/electric converter, Relays.

• Sensors:-

            Limit switches, push buttons, proximity sensors.

• Energy supply:-

Compressor, AC or DC power supply