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DESCRIPTION
introduction PLC s7TRANSCRIPT
SIEMENS SIMATIC S7SIEMENS SIMATIC S7
INTRODUCTION TOINTRODUCTION TO
PROGRAMMABLEPROGRAMMABLELOGICLOGIC
CONTROLCONTROL
Revision 2
ASSESSMENTASSESSMENTASSESSMENTASSESSMENT
»Practical Test 1 – 20%
»Practical Test 2 – 20%
»Assignment – 20%
»Final Exam – 30%
»Key Qualification – 10%
Topic 1Topic 1Topic 1Topic 1
Basic Principle of Basic Principle of Control TechnologyControl TechnologyBasic Principle of Basic Principle of
Control TechnologyControl Technology
Handout section 1.0
PPROGRAMMABLE ROGRAMMABLE LLOGIC OGIC CCONTROL ONTROL (PLC)(PLC)::
“ A digital electronic device that uses a
programmable memory to store instructions
and to implement specific functions such as
logic, sequence, timing, counting and
arithmetic to control machines and process. “
PLCPLCPLCPLC
What is CONTROL?
“ CONTROL is the process in a system in which
one or several input variables influence other
variables “
DIN 19226
Definition of ControlDefinition of ControlDefinition of ControlDefinition of Control
CCOONNTTRROOLL
SSYYSSTTEEMM
PPLLAANNTT
INFORMATION
COMMANDS ACTUATORS
SENSORS
A Simple View of a Control SystemA Simple View of a Control SystemA Simple View of a Control SystemA Simple View of a Control System
In open-loop control systems, output variables are influenced by the input variables.
Open-loop Control SystemOpen-loop Control SystemOpen-loop Control SystemOpen-loop Control System
LL
NN
It is characterized by continuous comparison of the desired value (or set point) with the actual value of the controlled variable.
CC
XsXsXiXi
Xi > XsXi > Xs
Xi < XsXi < Xs
LL
NN
Xi - Required valueXi - Required value
Xs - Actual valueXs - Actual value
Closed-loop Control SystemClosed-loop Control SystemClosed-loop Control SystemClosed-loop Control System
The essential difference between programmable control and traditional control technology may be summed up as follows:
» The functions are no longer determined by the wiring, but rather by the program
» Programming is simplified to enable symbols familiar to the control engineer to be used (contacts or logic graphic symbols)
PLC and Conventional Control SystemPLC and Conventional Control SystemPLC and Conventional Control SystemPLC and Conventional Control System
Handout section 1.1
LL
NN
S1S1
S2S2
K1K1
S1S1 S2S2
PLCPLC
K1K1
HardwireHardwire PLCPLC0 V0 V
24 VDC24 VDC
Hardwire and PLC Wiring DiagramsHardwire and PLC Wiring DiagramsHardwire and PLC Wiring DiagramsHardwire and PLC Wiring Diagrams
Handout section 1.3
K1K1
ComparisonComparisonComparisonComparison
Hardwired control systemsHardwired control systems
» The functions are determined by the physical wiring.
» Changing the function means changing the wiring
» Can be contact-making type (relays, contactors) or electronic type (logic circuits)
Programmable control systemProgrammable control system
» The functions are determined by a program stored in the memory.
» The control functions can be changed simply by changing the program.
» Consist of a control device, to which all the sensors and actuators are connected.
» During the late 1960s, General Motors (USA) was interested in the computer application to replace the hardwire systems.
» Bedford Associates (Modicon) and Allen Bradley responded to General Motors.
» The name given was “Programmable Controllers” or PC.
» Programmable Logic Controller or PLC was a registered trademark of the Allen Bradley.
» Later, PC was used for “Personal Computer” and to avoid confusion PLC for “Programmable Controller” and PC for a personal computer.
HISTORY OF PLCHISTORY OF PLCHISTORY OF PLCHISTORY OF PLC
» Implementing changes and correcting errors
» Pilot run - trial / test run
» Visual observation - online monitoring
» Speed of operation
» Reliability
» Documentation
ADVANTAGES OF PLC COMPARED TO HARDWIREADVANTAGES OF PLC COMPARED TO HARDWIREADVANTAGES OF PLC COMPARED TO HARDWIREADVANTAGES OF PLC COMPARED TO HARDWIRE
POWERPOWERSUPPLYSUPPLY
CENTRALCENTRALPROCESSINGPROCESSINGUNIT (CPU)UNIT (CPU)
INPUTINPUTMODULESMODULES
OUTPUTOUTPUTMODULESMODULES
MEMORYMEMORY(EPROM/RAM)(EPROM/RAM)
PG/PG/PCPC
Basic Structure of a PLCBasic Structure of a PLCBasic Structure of a PLCBasic Structure of a PLC
Handout section 1.4
InputInputDevicesDevices
» Input card
» Converter field voltage to 5V
acceptable by the CPU
Input ConnectionsInput ConnectionsInput ConnectionsInput Connections
Input Interface / ModuleInput Interface / ModuleInput Interface / ModuleInput Interface / Module
Handout section 1.4.1
From field wiring
To CPU / Memory
Detection Bridge
Signal Conditioning
Threshold Decision
Logic
Logic StatusLight
Opto-Isolation
» Output card
» Converter 5V to field voltage
to drive field devices
OutputOutputDevicesDevices
Output ConnectionsOutput ConnectionsOutput ConnectionsOutput Connections
Output Interface / ModuleOutput Interface / ModuleOutput Interface / ModuleOutput Interface / Module
From CPU / Memory
To field wiring
Switching Circuitry
Protection Circuitry
Logic StatusLight
Opto-Isolation
Logic
Handout section 1.4.2
Input / Output ModulesInput / Output ModulesInput / Output ModulesInput / Output Modules
» Digital input modules adapt digital signals e.g. from proximity sensors
» Digital output modules convert the internal signal level of PLC into digital process signals e.g. relays
» Analog input modules adapt analog process signals e.g. from transducers
» Analog output modules convert internal digital values of the PLC to analog process signals e.g. temperature controller
Central Processing Unit (CPU)Central Processing Unit (CPU)Central Processing Unit (CPU)Central Processing Unit (CPU)
What is a CPU?What is a CPU?
» The “brain” of a PLC
» Controlled by a program called the executive or operating system (OS)
» The executive is a collection of supervisory programs permanently stored in memory
Handout section 1.4.3
CPUCPUCPUCPU
Four basic types of CPU operations:Four basic types of CPU operations:
» Input and output operation
» Arithmetic and logic
» Reading or changing contents of memory locations
» Jump operations
CPUCPUCPUCPU
PROCESSOR
ACCUMULATOR
TIMERS, COUNTERS,
Memory
PII
INTERNALPROGRAMMEMORY
(RAM)
PIQ
SERIALINTERFACE
MEMORYSUBMODULE
(EPROM/EEPROM/
RAM)
» The CPU reads in input signal states, processes the control program and controls the outputs.
» The CPU provides internal Memory, timers and counters.
» Restart procedure can be preset and errors can be diagnosed using the CPU’s LEDs.
» The overall Reset on the CPU is used to delete the contents of the RAM.
» A PG or a Memory submodule is used to transfer the control program to the CPU.
CPUCPUCPUCPU
Program MemoryProgram MemoryProgram MemoryProgram Memory
Program memory
RAM (Random Access Memory)
• the memory contents can be read and written (modified)
• memory contents will be lost when the supply voltage fails
ROM (Read Only Memory) • the memory contents can be read, but cannot be modified
Handout section 1.4.4
Types of Program MemoryTypes of Program MemoryTypes of Program MemoryTypes of Program Memory
Alterable
UV erasableEPROM / REPROM
Semiconductor RAM
Programmable(Read-write memory)
Program memory
Non-programmable
Non-alterableROM / PROM
Electrically erasableEEPROM / EAPROM
SemiconductorEEPROM / EAPROM
Memory SubmodulesMemory SubmodulesMemory SubmodulesMemory Submodules
» EPROM SUBMODULE
An ultraviolet erasing device is used to delete the contents of the submodule
» EEPROM SUBMODULE
EEPROM submodule can be programmed or erased using a programmer
» RAM SUBMODULE
Can be used in addition to program storage; and used to test a control program during system startup
» The power supply module supplies the operational voltage for the PLC and provides backup for the RAM with a battery
» Backup battery
» The backup battery maintains the program and data when the PLC is switch off
» The backup battery has a service life of approximately 2 years
Power Supply ModulePower Supply ModulePower Supply ModulePower Supply Module
Handout section 1.4.5
PG
PS951CPU
Inputmodule
Outputmodule
Inputdevices
Outputdevices
External power supply
Hardware SummaryHardware SummaryHardware SummaryHardware Summary
Signal States and Sensor ContactsSignal States and Sensor ContactsSignal States and Sensor ContactsSignal States and Sensor Contacts
» There are only two different states:
SIGNAL STATE “0” = voltage not present = OFF
SIGNAL STATE “1” = voltage present = ON
» The sensor is a The sensor is Voltage at input Signal state
NO contact activated present 1
NO contact not activated not present 0
NC contact activated not present 0
NC contact not activated present 1
Handout section 1.6
Addressing of Inputs and OutputsAddressing of Inputs and OutputsAddressing of Inputs and OutputsAddressing of Inputs and Outputs
» The addressing of inputs and outputs are identified by an operand identifiers and the parameter
» Operand identifiers:
I - Input
Q - Output
» Parameter: (consists of a byte and a bit address)
0.0 … 0.7 (where 0. is the byte; 0…7 are the bit addresses)
1.0 … 1.7
Handout section 1.7
Types of AddressingTypes of AddressingTypes of AddressingTypes of Addressing
Absolute
» example: » A I 0.0» = Q 8.0 » A I0.4» = Q20.5» Call FC18
Symbolic
» example: » A “System_On”» = “System_On”» A “M_FORW”» =
“MOTOR_FOR”» Call “COUNT”
Symbol Address Data Type Comment
MOTOR_FOR Q20.5 BOOL Motor moves forward
COUNT FC18 FC18 Count bottles
SYSTEM_ON I0.0 BOOL Switch system ON
SYSTEM_ON Q8.0 BOOL Indicator: “System is ON”
M_FORW I0.4 BOOL Pushbutton: Motor forward
Max. 24 character Max. 80 character
Handout section 1.8.1
LAD - Ladder Diagram
( ) I 0.0 I 0.1 Q 4.0
Program Representation - LADProgram Representation - LADProgram Representation - LADProgram Representation - LAD
» The graphical representation of a control task using symbols to DIN 19239
» Very similar to traditional circuit diagrams, but the current paths are arranged horizontally instead of vertically
Program Representation - FBDProgram Representation - FBDProgram Representation - FBDProgram Representation - FBD
» The graphical representation of a control task using symbols to DIN 40700 and DIN 19239
» Inputs are arranged on the left side while outputs on the right
FBD - Function Block Diagram
&I 0.0
I 0.1Q 4.0
Handout section 1.8.2
Program Representation - STLProgram Representation - STLProgram Representation - STLProgram Representation - STL
» The control statement describes the task with mnemonic abbreviations of function designation (DIN 19239)
» Each method of representation has special characteristics and specific limits
» If certain rules are followed, translation into all three methods of representation is possible
STL - Statement List
A I 0.0A I 0.1= Q 4.0
Handout section 1.8.3
Operation And OperandOperation And OperandOperation And OperandOperation And Operand
Handout section 1.8.4
Operation;
Describes the function to be carried out (what is to be done)
e.g Binary operations, Digital operations and Organizational operations
Operand;
START FROM HERE
FBDFBDFBDFBDOPERAND + OPERATION
OPERATION + OPERAND
= Q 4.0
STLSTLSTLSTLOPERATION + OPERAND
A I 0.0A M 80.0
= Q 4.0
Operation And OperandOperation And OperandOperation And OperandOperation And Operand
LADLADLADLADOPERATION + OPERAND
( )Q 4.0
I 0.0 M 80.0
Handout section 1.8.4
&I 0.0
M 80.0
Program ExecutionProgram ExecutionProgram ExecutionProgram Execution
PLC Scan Function:PLC Scan Function:
» Read the status of all inputs and outputs
» Examine the application program instructions
» Execute the control program
Handout section 1.9
Linear Program ScanningLinear Program ScanningLinear Program ScanningLinear Program Scanning
» Statements are scanned linearly
» At the end of the program, scanning starts again from the beginning
» This is also referred to as cyclical scanning
» Linear program scanning is used mainly for simple, small-scale control schemes
Handout section 1.9.1
» OB = Organization Block
» Every program must have OB1
» When the PLC is set to run, the PLC will look for OB1 only in the user memory and execute it
» Other blocks can be called from OB1 with the “jump” command
OB1OB1OB1OB1
Cyclic program execution
Linear program scanning
OB1
A I 0.0A I 0.1= Q 4.0:::BE
» Complex tasks are subdivided into clearly differentiated sub-tasks
» i.e. the program is divided into small, easy-to-follow program blocks, organized according to different functions
Handout section 1.9.2
Structured Program ScanningStructured Program ScanningStructured Program ScanningStructured Program Scanning
OB1
JU FC 1
JU FC 4:::BE
FC1
A I 0.0A I 0.1= Q 4.0:::BE
FC4
A Q 4.0A I 0.2= Q 5.0:::BE
Cyc
lic p
rogr
am e
xecu
tion
Structured program scanning
Operatingsystem
Linear programming
OB1Network 1A I 0.6A I 0.7= Q 4.2Network 2A I 0.7A I 0.5= Q 4.3Network 3A Q 4.2A I 0.2= Q 5.5 BE
Network 1JU FC 1
JU FC 4
BE
OB 1
Network 1A I 0.6A I 0.7= Q 4.2Network 2A I 0.7A I 0.5= Q 4.3BE
Network 1A Q 4.2A I 0.2= Q 5.5 BE
FC 1
FC 4
Structured programming
Program ExecutionProgram ExecutionProgram ExecutionProgram Execution
Handout section 1.9.3
A I 0.0
A I 0.1
= Q 4.0
O I 0.5
O I 0.7
= Q 4.3
BE:
PII
PIQ
24 VDC GNDInput
moduleProcess
input imageProcess
output image
Program inthe RAM
Outputmodule
Input cycle Program execution Output cycle
I 0.1
I 0.0
I 0.5
I 0.7
Q 4.0
Q 4.3
1
0
1
1
0
1
» A buffer of input signals
» Update just before program execution starts
» Not updated during program execution
» Logic executed based on status in PII
» Prevent signal transition during program cycle to affect the program
Update PII
ExecuteProgram
Logic
Update Output
PII - Process Input ImagePII - Process Input ImagePII - Process Input ImagePII - Process Input Image
» Updated by the program logic during program execution
» The contents of PIQ are transferred to the output module at the end of OB1
OB1 PIQ
Copy PIQ to Output Module
PIQ - Process Output ImagePIQ - Process Output ImagePIQ - Process Output ImagePIQ - Process Output Image
BLOCK TYPESBLOCK TYPESBLOCK TYPESBLOCK TYPES
» ORGANISATION BLOCKS (OB) – Interface between the operating system and the user program
» FUNCTIONS (FC) - Contains a partial functionality of the program
» DATA BLOCKS (DB) – Are data areas of the user program in which user data are managed in a structured manner
» SYSTEM FUNCTION BLOCKS (SFB), SYSTEM FUNCTIONS (SFC) - SFBs and SFCs are integrated in the S7 CPU and allow you access to some important system functions
» FUNCTION BLOCKS (FB) - FBs are blocks with a “memory” which you can program yourself
» INSTANCE DATA BLOCKS (DB) - Instance DBs are associated with the block when an FB/SFB is called. They are created automatically during compilation
Handout section 1.9.4
JU FC 1.......BE
OB1
FC 1
JU FC4.....BE
FC 4
JU FC 7.....BE
FC 7
A I ..........BE
Block Nesting DepthBlock Nesting DepthBlock Nesting DepthBlock Nesting Depth
The Operand Areas (for Siemens S5-95U PLC)The Operand Areas (for Siemens S5-95U PLC)The Operand Areas (for Siemens S5-95U PLC)The Operand Areas (for Siemens S5-95U PLC)
» I (Input)Interface from the process to the programmable controller
» Q (Output)Interface from programmable controller to the process
» M (Memory/Flag)Memory for intermediate results of binary operations
» T (Timer)Memory for implementing timers
» C (Counter)Memory for implementing counters
Handout section 1.9.5
The Addressing of Siemens S7The Addressing of Siemens S7The Addressing of Siemens S7The Addressing of Siemens S7
Operand Areas Addressing
Input (I) 0.0 to 0.71.0 to 1.72.0 to 2.73.0 to 3.7
Output (Q) 4.0 to 4.7
5.0 to 5.7
8.0 to 8.7
9.0 to 9.7Counters (C) 0 to 63Timers (T) 0 to 127
Handout section 1.9.6
Topic 3Topic 3Topic 3Topic 3
Programming Basic Programming Basic FunctionsFunctions
Programming Basic Programming Basic FunctionsFunctions
Handout section 3.0
The Stages of Project PlanningThe Stages of Project PlanningThe Stages of Project PlanningThe Stages of Project Planning
Description of the Problem
Assignment Lists
Rough Structure of the Control System
Program Structure
Detailed Structure of the Control System
Handout section 3.1
The Stages of Project PlanningThe Stages of Project PlanningThe Stages of Project PlanningThe Stages of Project Planning
Problem Description» it consists of process schematic, a short description of the task
definition, and a list of the sensors and actuators
Assignment List» the sensors and actuators are allocated to the parameters of the
programmable controller» it contains a short functional description as well as the device
identifier
The Stages of Project PlanningThe Stages of Project PlanningThe Stages of Project PlanningThe Stages of Project Planning
Rough Structure of the Control System» it contains all sub-functions of the process with relevant sensors,
actuators and indicators
Program Structure» it determines the order in which the LAD, FBD or STL diagram to
be drafted
Detailed Structure of the Control System» using the assignment list and the program structure, the flow chart
contained in the rough structure is refined
STL
A I 0.0A I 0.1= Q 4.0
&I 0.0
I 0.1Q 4.0
FBD
Programming AND OperationProgramming AND OperationProgramming AND OperationProgramming AND Operation
( )I 0.0 I 0.1 Q 4.0
LAD
Handout section 3.2
STL
O I 0.0O I 0. 1= Q 4.0
>= 1
FBD
I 0.0
I 0.1Q 4.0
OR OperationOR OperationOR OperationOR Operation
Handout section 3.3
LAD
( )I 0.0
I 0.1
Q 4.0
STLA I 0.0A I 0.1OA I 0.2A I 0.3= Q 4.0
AND - before - OR OperationAND - before - OR OperationAND - before - OR OperationAND - before - OR Operation
Handout section 3.4
( )I 0.0 I 0.1
I 0.2 I 0.3
Q 4.0LAD
I 0.0
I 0.1
I 0.2
I 0.3
I 0.0
I 0.1
I 0.2
I 0.3
Q 4.0
FBD
>= 1
&
&
STLA (O I 0.0O I 0.2)A (O I 0.1O I 0.3)= Q 4.0
OR - before - AND OperationOR - before - AND OperationOR - before - AND OperationOR - before - AND Operation
Handout section 3.5
( )I 0.0 I 0.1
I 0.2 I 0.3
Q 4.0LAD
I 0.0
I 0.1
I 0.2
I 0.3
I 0.0
I 0.1
I 0.2
I 0.3
Q 4.0
FBD
&>= 1
>= 1
Handout section 3.6
Programming of NC Contacts and NO ContactsProgramming of NC Contacts and NO ContactsProgramming of NC Contacts and NO ContactsProgramming of NC Contacts and NO Contacts
» Physical connection PLC programming The sensor is Signal state
NO contact NO contact activated 1
NO contact NO contact not activated 0
NO contact NC contact activated 0
NO contact NC contact not activated 1
NC contact NO contact activated 0
NC contact NO contact not activated 1
NC contact NC contact activated 1
NC contact NC contact not activated 0
Latching OutputLatching OutputLatching OutputLatching Output
Handout section 3.7
SET Priority / Dominant SET RESET Priority / Dominant RESET
S1
S2
K1
K1
S3
S4
K2
K2
RS Memory FunctionRS Memory FunctionRS Memory FunctionRS Memory Function
Handout section 3.8
SET Priority / Dominant SET
=R
S Q
S1
S2
( )K1
S3
S4
K2
K2
RS Memory FunctionRS Memory FunctionRS Memory FunctionRS Memory Function
RESET Priority / Dominant RESET
=S
R Q
S4
S3
( )K2
S1
S2
K1
K1
Try This !Try This !Try This !Try This !
Will the output Q 4.0 be activated when you activate:
» I 0.0 and I 0.1 ?
» I 0.2 and I 0.3 ?
» I 0.4 and I 0.5 ?
( )I 0.0 I 0.1 Q 4.0
LAD
( )I 0.2 I 0.3 Q 4.0
( )I 0.4 I 0.5 Q 4.0
The AnswerThe AnswerThe AnswerThe Answer
» I 0.0 and I 0.1 = NO!
» I 0.2 and I 0.3 = NO!
» I 0.4 and I 0.5 = YES …… but why ?
When I0.0 and I0.1 Are Activated...When I0.0 and I0.1 Are Activated...When I0.0 and I0.1 Are Activated...When I0.0 and I0.1 Are Activated...
» the PLC registers in the PIQ that Q 4.0 is “1”
» the PLC registers in the PIQ that Q 4.0 is “0”
» the PLC registers in the PIQ that Q 4.0 is “0”
so, Q 4.0 = “0”
( )I 0.0 I 0.1 Q 4.0
LAD
( )I 0.2 I 0.3 Q 4.0
( )I 0.4 I 0.5 Q 4.0
When I0.2 and I0.3 Are Activated...When I0.2 and I0.3 Are Activated...When I0.2 and I0.3 Are Activated...When I0.2 and I0.3 Are Activated...
» the PLC registers in the PIQ that Q 4.0 is “0”
» the PLC registers in the PIQ that Q 4.0 is “1”
» the PLC registers in the PIQ that Q 4.0 is “0”
so, Q 4.0 = “0”
( )I 0.0 I 0.1 Q 4.0
LAD
( )I 0.2 I 0.3 Q 4.0
( )I 0.4 I 0.5 Q 4.0
When I0.4 and I0.5 Are Activated...When I0.4 and I0.5 Are Activated...When I0.4 and I0.5 Are Activated...When I0.4 and I0.5 Are Activated...
» the PLC registers in the PIQ that Q 4.0 is “0”
» the PLC registers in the PIQ that Q 4.0 is “0”
» the PLC registers in the PIQ that Q 4.0 is “1”
this time, Q 4.0 = “1”
( )I 0.0 I 0.1 Q 4.0
LAD
( )I 0.2 I 0.3 Q 4.0
( )I 0.4 I 0.5 Q 4.0
The Problem of Repetitive OutputsThe Problem of Repetitive OutputsThe Problem of Repetitive OutputsThe Problem of Repetitive Outputs
» Therefore, when the same output is used more than once in the program, only the last state of the output will be valid due to the PLC dynamically updating the PIQ (Process Output Image)
» MEMORY = Memory for intermediate results of binary operations
» Memory can be treated as flags/variables
» Memory can be used to solve the problem of repetitive outputs
Using Memory…...Using Memory…...Using Memory…...Using Memory…...
( )I 0.0 I 0.1 M 100.0
( )I 0.2 I 0.3 M 100.1
( )I 0.4 I 0.5 M 100.2
( )M 100.0 Q 4.0
M 100.1
M 100.2
RLO STATA Q 4.0 …… ……A ( …… …… O I 0.1 …… …… O I 0.2 …… …… O I 0.3 …… …… )= Q 5.0 …… ……
Result of Logic Operation (RLO)Result of Logic Operation (RLO)Result of Logic Operation (RLO)Result of Logic Operation (RLO)
>=1
Q 4.0
I 0.0I 0.1I 0.2
Q 5.0&
Mathematics Logic Operation
Multiplication Before Addition
4 X 8 + 3 X 2 = 38AND before OR
RLO STATA I 0.0 1
1A I 0.1 1
1O 1 \A I 0.2 0
0A I 0.3 0
1= Q 4.0 1 1
Parenthesized FunctionParenthesized FunctionParenthesized FunctionParenthesized Function
Addition Before Multiplication
4 X (8 + 3 ) X 2 = 88
Parenthesized FunctionParenthesized FunctionParenthesized FunctionParenthesized Function
Mathematics Logic Operation
OR before AND
RLO STATA I 0.0 1 1A ( 1 \O I 0.1 1 1O I 0.2 1 0) 1 \A I 0.3 1 1= Q 4.1 1 1
Topic 4Topic 4Topic 4Topic 4
Numerical Systems and Numerical Systems and Data FormatsData Formats
Numerical Systems and Numerical Systems and Data FormatsData Formats
Handout section 4.0
Comparison of Number SystemsComparison of Number SystemsComparison of Number SystemsComparison of Number Systems
Handout section 4.1
Bit, Byte and Word AddressesBit, Byte and Word AddressesBit, Byte and Word AddressesBit, Byte and Word Addresses
Handout section 4.2
Load and Transfer OperationsLoad and Transfer OperationsLoad and Transfer OperationsLoad and Transfer Operations
Characteristics:» They are used to perform operations on a whole byte or word in
memory» They are unconditional operations i.e. They are performed by the
processor in each cycle
Functions:» Exchange information between various operand areas» Prepare times and counts for further processing» Load constants for program processing
Handout section 4.4
Load OperationLoad OperationLoad OperationLoad Operation
Byte d Byte c Byte b Byte a
0 IB 0Byte b Byte a
0 IB 10 IB 0
PII
IB 0
IB 1
L IB 0L IB 1
Information from PII
ACCUM 2 ACCUM 1
Transfer OperationTransfer OperationTransfer OperationTransfer Operation
Byte d Byte c Byte b Byte a
Byte d Byte c
PIQ
Byte a QB 0
T QB 0
Information in the PIQ
ACCUM 2 ACCUM 1
Byte b Byte a
Arithmetic and Assignment of AccumulatorArithmetic and Assignment of AccumulatorArithmetic and Assignment of AccumulatorArithmetic and Assignment of Accumulator
Handout section 4.5
Binary Coded Decimal (BCD)Binary Coded Decimal (BCD)Binary Coded Decimal (BCD)Binary Coded Decimal (BCD)
Handout section 4.6
Topic 5Topic 5Topic 5Topic 5
Timer OperationsTimer OperationsTimer OperationsTimer Operations
Handout section 5.0
Fault Indication with Timer FunctionFault Indication with Timer FunctionFault Indication with Timer FunctionFault Indication with Timer Function
Handout section 5.0
Handout section 5.1
Inputs and Outputs of a TimerInputs and Outputs of a TimerInputs and Outputs of a TimerInputs and Outputs of a Timer
Handout section 5.2.1
Types of Timer - Pulse Timer (SP)Types of Timer - Pulse Timer (SP)Types of Timer - Pulse Timer (SP)Types of Timer - Pulse Timer (SP)
Handout section 5.2.2
Extended Pulse Timer (SE)Extended Pulse Timer (SE)Extended Pulse Timer (SE)Extended Pulse Timer (SE)
Handout section 5.2.3
On Delay Timer (SD)On Delay Timer (SD)On Delay Timer (SD)On Delay Timer (SD)
Handout section 5.2.4
Stored On Delay Timer (SS)Stored On Delay Timer (SS)Stored On Delay Timer (SS)Stored On Delay Timer (SS)
Handout section 5.2.5
Off Delay Timer (SF)Off Delay Timer (SF)Off Delay Timer (SF)Off Delay Timer (SF)
Load and Transfer Timer ValueLoad and Transfer Timer ValueLoad and Transfer Timer ValueLoad and Transfer Timer Value
Return OperationsReturn OperationsReturn OperationsReturn Operations
» BE (Block End)» the return operation is performed unconditionally» it is always the last statement in the block
» BEU (Block End Unconditional)» the return operation is performed unconditionally» statements can follow BEU, but they will not be executed» BEU is often used during commissioning so that individual parts of the
program can be tested
» BEC (Block End Conditional)» the return is made dependent on a condition and is only performed if the
condition is satisfied
Handout section 5.4
Block End Operations BEC, BEU and BEBlock End Operations BEC, BEU and BEBlock End Operations BEC, BEU and BEBlock End Operations BEC, BEU and BE
::JU FC1:A I 0.0:JC FC 2::BEU::JU FC3:BE
::A I 0.6:BEC::BE
:::BE
:::BE
OB1
FC1
FC2
FC3
is always executed
is executed only when I 0.6 = “0”
is executed only when I 0.0 = “1”
is not executed
is not executed
System
Topic 6Topic 6Topic 6Topic 6
Counter OperationsCounter OperationsCounter OperationsCounter Operations
Handout section 6.0
Handout section 6.0
CounterCounterCounterCounter
Counter OperationsCounter OperationsCounter OperationsCounter Operations
CU - count up
CD - count down
S - set counter to the count value (CV)
CV - the count value
R - reset the counter (count value = 0)
BI - counter output as binary number
DE - counter output as BCD number
Q - counter status
Q = 0 when count value = 0
Q = 1 when count value > 1
Handout section 6.2
Timing DiagramTiming DiagramTiming DiagramTiming Diagram
Counter InputCounter InputCounter InputCounter Input
Handout section 6.3
Counter OutputCounter OutputCounter OutputCounter Output
Handout section 6.4
ComparatorComparatorComparatorComparator
Types of comparison:
!=F compare for equal to
><F compare for not equal to
>F compare for greater than
>=F compare for greater than or equal to
<F compare for less than
<=F compare for less than or equal to
Comparison OperationsComparison OperationsComparison OperationsComparison Operations
» The comparison operations compare two digital values in accumulator 1 and accumulator 2
» The result of comparison produces an RLO:
» Comparison satisfied RLO = “1”
» Comparison not satisfied RLO = “0”
Handout section 6.4
ComparatorComparatorComparatorComparator