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SiemensS7-200 PLC training courses



PLC history

• Classical control

- More complicated - Longer time for maintenance

- Time consuming troubleshooting

- Occupies larger area in switchboards

- Requires more wiring

- Standard reliability



History

• Large projects requirements

- More inputs and outputs points

-Large program memory

-Several programming instructions

-Communication with other equipments

-Deal with analogue signals

-Deal with large number of counters, timers and markers



History

• Historical view



Course contents

• Introduction to PLC

• Bit logic • compare

• Timers

• Counters

• Memory instructions

• Analog I/O

• Move , shift

• Practical examples



Introduction

• What is a PLC



Introduction

• Basic PLC operation



introduction

• S7 200 family



introduction

• S7-200 configuration



introduction


mode switch and analog adjustment



introduction


optional cartidge



Introduction


expansion modules

I t d ti



Introduction


status indicator

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Introduction


I/O numbering

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Introduction


inputs

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Introduction


outputs

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Introduction


programming software



Analogue I/O = Typical analogue signals from 0-10 VDC or 4-20 mA

= They are used to represent changing values such asspeed, temperature, weight and level

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Introduction

Analogue outputs may be used to produce

variable reference signals for devices such as:

# Control valves

# Chart recorders # Electric motor drives

# Pressure transducers

# Analogue meters

I t d ti



Introduction

I t d ti



Introduction

I t d ti



Introduction

PLC P i



PLC Programming

Programming lang ages



Programming languages

Statement list Function block

Ladder diagram

The instructions are representedby graphic symbols:

Contacts, Coils & Boxes

The ladder diagram is the mostpopular programming language

Instructions



Instructions

Standard instructions:

They are used in most programs.

Examples: timer, counter, math, logical, incr., decr. and move

High speed instructions:

They allow for events and interrupts to occur independently ofthe PLC scan time.

Examples: High speed counters and interrupts

Special instructions:

They are used to manipulate data

Shift, table, conversion, real time instruction.

Bit Logic instruction



Bit Logic instruction

Normally Open contact

Normally Open Immediate contact

Normally Closed contact

Not contact

Normally Closed Immediate contact

Positive Transition contact

Negative Transition contact

Input Instructions

Input contacts example



Input contacts example

Output instructions



Output instructions

Output Instruction

No Operation instruction

Output Immediate instruction

Set (N bits) instruction

Reset (N bits) instruction

Set Immediate (N bits) instruction

Reset Immediate (N bits) instruction

Output Set & Reset example



Output, Set & Reset example

Starting a motor



Starting a motor

Hard wired DOL starting



Hard-wired DOL starting

Induction Motor

Circuit Breaker

Contactor

ThermalOverload

InductionMotor

Aux. contact

Contact coil

Stop

O.L. contact

Start

Using PLC



Using PLC

Before start

Starting

After start



Stopping

Input & Output connections



Input & Output connections

Timer instructions



Timer instructions

On-Delay Timer

Retentive On-Delay Timer

Off-Delay Timer



Off-Delay timer



Off-Delay timer

The Off-Delay Timer is used to delay turning an output OFF for afixed period of time after the input turns OFF.

When (IN) turns ON, the timer bit turns ON immediately, and thecurrent value is set to 0.When (IN) turns OFF, the timer counts till PT and the timer bitturns OFF and the current value stops counting.

If the input is OFF for a time shorter than PT, the timer bitremains ON.

Timers numbers & resolutions



Timers numbers & resolutions

Note

You cannot share the same timer numbers for TOF and TON.For example, you cannot have both a TON T32 and a TOF T32.

Timer examples



Timer examples

On-Delay

Off-Delay

Retentive

On-Delay

Hard-wired on-delay timer



Hard-wired on-delay timer

Timer example



Timer example

TONR example



TONR example

Timer example



Timer example

Counter instructions



Counter instructions

Up counter

Up/down counter

Down counter

A bottling machine, for example, may use a counter to countbottles into groups of six for packaging.

Up-counter



Up counter

It counts up on the rising edges of the Count Up (CU)

input.

(PV), the counter bit>When the current value (Cxxx)(Cxxx) turns on.

The counter is reset when the Reset (R) input turns on.

Up/Down counter



Up/Down counter

It counts up on rising edges of the Count Up (CU) input.It counts down on the rising edges of the Count Down(CD) input.

(PV), the counter bit>When the current value (Cxxx)

(Cxxx) turns on.

The counter is reset when the Reset (R) input turns on.

Down counter



Down counter

It counts down from the PV on the rising edges of the (CD) input .

When the current value is equal to zero, the counter bit (Cxxx)turns on.

The counter resets the counter bit (Cxxx) and loads the currentvalue with the (PV) when the load input (LD) turns on.

Down-counter example



Down counter example

Up/down-counter example



Up/down counter example

Counter example



Counter example

A counter might be used to keep track of the number of vehiclesin a parking lot. As vehicles enter the lot through an entrancegate, the counter counts up. As vehicles exit the lot through anexit gate, the counter counts down. When the lot is full a sign atthe entrance gate turns on indicating the lot is full.

The ladder logic



The ladder logic

Memory types



Memory types

• You can access data in many CPU memory areas

- process image input register (I)

- process image output register (Q)

- variable memory area (V)

- Bit memory area (M)

- sequence control relay memory area (S)- special memory bits (SM)

- local memory area (L)

- Timer memory area (T)- counter memory area (C)

- Analog inputs (AI)

Memory addressing



Accessing a Bit of Data in the CPU Memory (Byte.bit Addressing)

e o y add ess g

Memory addressing



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You can access data in many CPU memory areas (V, I, Q, M, S, L,and SM) as:bytes, words, or double words by using the byte-address format.

Memory types



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• Process-image input register (I)

Format:

Bit I[byte address].[bit address] I0.1Byte, Word, Double Word I[size][starting byte address] IB4

• Process-image output register (Q)Format:Bit Q[byte address].[bit address] Q1.1

Byte, Word, Double Word Q[size][starting byte address] QB5

• Variable memory area (V)You can use V memory to:

•store intermediate results of the control logic operations.•store other data pertaining to your process or task.

Format:Bit V[byte address].[bit address] V10.2Byte, Word, Double Word V[size][starting byte address] VW100

Memory types



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• Sequence control relay area (S)

They are used to organize machine operations or steps into equivalent

program segments. SCRs allow logical segmentation of the controlFormat:Bit S[byte address].[bit address] S3.1Byte, Word, Double Word S[size][starting byte address] SB4

• Special memory bits (SM)

The SM bits provide a means for communicating information between theCPU and your program. You can use these bits to select and control someof the special functions of the S7-200 CPU, such as:• A bit that turns on for the first scan cycle

• Bits that toggle at fixed rates

• Bits that show the status of math or operational instructionsFormat:Bit SM[byte address].[bit address] SM0.1Byte, Word, Double Word SM[size][starting byte address] SMB86

Memory types



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• Local memory area (L)

The S7-200 PLCs provide 64 bytes of local (L) memory of which 60 can be

used as scratchpad memory or for passing formal parameters to subroutines.Format:Bit L [byte address].[bit address] L0.0Byte, Word, Double Word L [size] [starting byte address] LB33

Memory types



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• Analog inputs (AI)

The S7-200 converts a real-world, analog value (such as temperatureor voltage) into a word-length (16-bit) digital value. You access thesevalues by the area identifier (AI), size of the data (W), and the startingbyte address. Since analog inputs are words and always start oneven-number bytes (such as 0, 2, or 4), you access them with even-number byte addresses (such as AIW0, AIW2, or AIW4),as shown inFigure Analog input values are read-only values.

Format: AIW [starting byte address] AIW4

Memory types



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The S7-200 converts a word-length (16-bit) digital value into a currentor voltage, proportional to the digital value (such as for a current or

voltage). You write these values by the area identifier (AQ), size of thedata (W), and the starting by address. Since analog outputs are wordsand always start on even-number bytes (such as 0, 2, or 4), you writethem with even-number byte addresses (AQW0, AQW2, AQW4),

Format: AQW [starting byte address] AQW4

•Analog outputs (AQ)

Move instructions



The Move Byte instruction moves the input byte(IN) to the output byte (OUT). The input byte is notaltered by the move.

The Move Word instruction moves the input word(IN) to the output word (OUT). The input word isnot altered by the move.

The Move Double Word instruction moves the inputdouble word (IN) to the output double word (OUT).The input double word is not altered by the move.

The Move Real instruction moves a 32-bit, real inputdouble word (IN) to the output double word (OUT).The input double word is not altered by the move.

The block move instructions



The Block Move Byte instruction moves the number of

bytes (N) from the input address IN to the output addressOUT. N has a range of 1 to 255.

Example

Move byte immediate instructions



The Move Byte Immediate Write instruction reads fromlocation IN and writes to physical output OUT.

The Move Byte Immediate Read instruction readsphysical input IN and writes the result in OUT.

Analogue I/O



= Typical analogue signals from 0-10 VDC or 4-20 mA

= They are used to represent changing values such asspeed, temperature, weight and level

g

=The expansion module converts the standard voltage andcurrent values to 12-bit digital representation. These digital

values are transferred to the PLC for use in its program



Analogue outputs may be used to produce

variable reference signals for devices such as:

# Control valves

# Chart recorders # Electric motor drives

# Pressure transducers

# Analogue meters

Analog o/p example



g p p

Analog i/p example



g p p

Analog i/p example



g p p

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