بسم الله الرحمن الرحيم (وقل رب زدني علما ) ( رب اشرح لي صدري ويسر لي امري واحلل عقدة من لساني يفقهوا قولي )

Programmable Logic controllers (PLC) BY : Marwan Hammouda Sabri Mohammed Radi To : Dr. Basil Hamad The Islamic University Of Gaza Faculty Of Engineering Electrical Engineering Department Advanced Technical English

Functions of Controllers : OOOOn-off control SSSSequential control FFFFeedback control MMMMation control

Control Devices: MMMMechanical control PPPPneumatic control EEEElectromechanical control EEEElectronic control CCCComputer control

Programmable Logic controllers PLCs WWWWere introduced in 1968 WWWWere primarily intended to replace relay devices, so it is appropriate to be familiar with the components used in relay devices

PLCs (continue) TTTThe National Electrical Manufacturing Associatioin (NEMA) defines the PLC as “A digitally operating electronic apparatus which uses a programmable memory for the internal storage of instructions by implementing specific functions such as logic sequencing, timing, counting, and arithmetic to control, through digital or analog input/output modules, various types of machines or processes. The digital computer which is used to perform the functions of a programmable controller is considered to be within this scope. Excluded are drum and other similar mechanical sequencing controllers."

Why is the PLC ?  C C C Cost effective for controlling complex systems. FFFFlexible and can be reapplied to control other systems quickly and easily CCCComputational abilities allow more sophisticated control. TTTT rouble shooting aids make programming easier and reduce downtime RRRR eliable components make these likely to operate for years before failure

PLC Architecture

PLC Components : PPPProcessor : The processor (CPU) scans the status of the input peripheral, examines the control logic to see what action to take, and then excute the appropriate output response MMMMemory : the control program and the peripheral status are stored in the memory ROM( Read Only Memory ) RAM (Random Access Memory), PROM (Programmable Read Only Memory), EEPROM (Electric Erasable Programmable ROM), EPROM (Erasable Programmable Read Only Memory), EAPROM (Electronically Alterable Programmable

PLC Components (continue)  Input/Output : modular plug-in periphery modular plug-in periphery Ac voltage input and output Ac voltage input and output Dc voltage input and output Dc voltage input and output Low level analog input Low level analog input High level analog input and output High level analog input and output Specail purpose modulas Specail purpose modulas  Powre supply : Ac power  Peripherals : Hand-Held Programmer ( HHP) CRT programmer CRT programmer Operetor console Operetor console Printer Printer Simulator Simulator EPROM loader EPROM loader Graphics processor Graphics processor

A Hand Held Programmer

PLC Programming  Ladder Diagram - most common  Structure Text Programming (ST)  Functional Block Programming (FB)  Instruction List (IL)  Sequential Function Chart (SFC)

Ladder Diagram A ladder diagram (also called contact symbology) is a means of graphically representing the logic required in a relay logic system. Rail Rung

PLC Ladder Diagram INSTRUCTIONS 1) Relay, 2) Timer and counter, 3) Program control, 4) Arithmetic, 5) Data manipulation, 6) Data transfer, and 7) Others, such as sequencers.  Hint : Relay, timer and counter instructions are the most fundemental because they correspond to what is on a ladder diagram and are avaliable on all PLCs so we limit our disscusion to them

Relay A Relay consists of two parts, the coil and the contact(s). Contacts: a. Normally open-| |- b. Normally closed-|/|- c. Positive transition sensing -|P|- d. Negative transition sensing-|N|- Coil: a. Coil-( )- b. negative coil-(/)- c. Set Coil-(S)- d. Reset Coil-(R)- contact coil input

Relay (continue) Coil: e. Retentive memory Coil-(M)- f. Set retentive memory Coil-(SM)- g. Reset retentive memory Coil -(RM)- h. Positive Transition-sensing Coil-(P)- h. Negative Transition-sensing Coil-(N)- (set coil latches the state, reset coil deenergize the set coil. retentive coil retain the state after power failure.)

TIMERS AND COUNTERS Timers: a. Retentive on delay- (RTO)- a. Retentive on delay- (RTO)- b. Retentive off delay- (RTF)- b. Retentive off delay- (RTF)- c. Reset-(RST)- c. Reset-(RST)-Counter: a. Counter up-(CTU)- a. Counter up-(CTU)- b. Counter down-(CTD)- b. Counter down-(CTD)- c. Counter reset-(CTR)- c. Counter reset-(CTR)- RTO counting stop counting resume RTF stop counting stop True False True Input RTO reach PR value, output ON RTF reach PR value, output OFF PR value in 0.1 second

TIMERS AND COUNTERS(continue) 5 TIMER COUNTER

THANKS ALL