Programmable Logic Controllers 182 312 Programmable Logic Controllers Dr.Anucha Saengrung October 11st ,2011

Today Outline Course Syllabus History of PLC class History of PLCs Advantages of PLCs Example of PLC Applications How does PLC work? S7 Family

Big Picture of the Whole PLC Course Course Syllabus Big Picture of the Whole PLC Course Hardware PLC Operations AIs, AOs, PID Control STEP7, SCL, GRAPHS PROFIBUS

History of PLCs In 1968, engineers at Hydramatic division of General Motor Corporations invented the first PLC. - Use program to control the machine - More Efficient, Smaller than the existing controller - Easier to maintenance, lower cost - Cheaper when compared to control by using relays In 1970, using microprocessor in PLC In 1975, using computer technology both hardware and software with PLCs In1993 IEC (International Electro-technical Commission) specified the standards of PLC system, PLC languages, data communications, etc.

History of PLCs At present, PLCs have higher performances - Faster CPU, Higher memory - Multi-processor - Using remote I/Os - Control using Intelligent Module - Communicate via Ethernet Protocol, Profibus, ASI-bus - etc.

Advantages of PLCs

Advantages of PLCs

Advantages of PLCs PLC Relays/Magnetic Contactors Cost Lower Higher Size Compact Bigger Size Speed Fast Slower Tolerance to noise Good Excellent Installation Easy Take more time for design and installation Ability to control complex tasks yes Difficult to do Ability to change the control sequences Take time and efforts Maintenance and trouble shooting when there is a problem Maintenance is rarely required. Easy for trouble shooting. Have to maintenance the coils and contacts. Hard to trouble shooting

Examples of PLC applications Automotive Industry

Examples of PLC applications Airports

PLANT PLC How does PLC work? I CPU Sensors - Switches Actuators Inputs Outputs CPU DIs, AIs DOs, AOs Sensors - Switches Transducers Photocells Actuators - Valves - Inverter - Heater - Motor PLANT

S7 Family S7-200 S7-300* S7-400

PLCs in the market PLCs Europe SIEMENS ABB Honeywell Schneider National Instrument … Asia OMRON Mitsubishi Yokokawa