plc8-200417125816.pdf

Programmable Logic
Controllers (PLC)
Overview
Nereus Fernandes

Agenda
• Basic Theory, PLC Types
• SCADA-HMI
• Drive Control using PLC
• Protocols-Modbus, OPC UA
• PLC Selection, Programming Guidelines
• Industrial Automation Hierarchy
• Other Closely Related Controllers and Networks
– Safety Instrumented Systems
– Building Automation Systems
– Substation Automation Systems
– DCS (Distributed Control System)
– RTU (Remote Terminal Unit)
– Machine Vision
– Position & Motion Systems
– Robotics
– CNC Machines
– PAC (Programmable Automation Controller)
• Emerging Technologies
– MQTT Protocol & PLC intergation with Industrial IIoT and the Cloud
• H/w & S/w to build a PLC
• Industrial Cyber Security
• Dual Use Technology

PLC Trends…
• Today the PLC is increasingly integrated into the Industrial Automation and
IT networks
• PLCs today have extensive functionality and are much more than just
Ladder Logic…
– Besides programming the PLC, the Automation Engineer is also required to set-
up network infrastructure for Ethernet & Field-buses, to code scripts for SCADA,
SQL Queries for Database & API-calls for ERP and integration with the Cloud
• Wide and often confusing choices of PLC vendors, hardware platforms and
software programming options are now available
– The ultimate choice of the hardware and software is driven by : required
features, cost, expertise available, vendor support, historical use in the
application – existing installations and the need for uniformity in the plant / across
plants of an organization
• Most books and presentations available - only focus on basics and do not
highlight the breadth of advanced PLC features and technology
• The aim of this presentation is
– to provide a broad overview of the Industrial Automation market-place and show
where the PLC fits in. The reader is encouraged to look at the technical
documentation of the various vendors to learn more about products of interest
– Highlight the advanced features available on most PLCs now-a-days
– to stimulate interest in the inner workings, design and construction of the PLC
hardware and software - rather than treating it as a black-box

PLC Trends… Into the future…
• The PLC has been the control and computational work-horse of the industry for the past 50 years
• Industrial IoT documentation in the early 2010s largely mentioned examples based on Arduino
and RasberryPi hardware. This was to encourage trial of the principles on economical hardware.
However it could lead to the assumption that PLCs were not suitable for IoT and did not have
much of a future. While initially PLC manufacturers were a little slow to react – today there is
broad and robust support for IoT Technologies in PLC hardware and almost all Industrial
Automation Software.
• Ability to simultaneously use Multiple Processors – PLC-CPU, Motion Controller, CNC Controller,
Robot Controller, Programmable Embedded System & FPGA Special Purpose Controllers,
Tensor/Neural Processing Units, High Speed Data-Logger, Communication Modules with multiple
network support, Large Memory – turn today’s PLCs into powerful multiple processor platforms
linked by High-Speed PLC Back-Plate Bus and other High-Speed Communication Busses
• With the continuous innovations in the PLC world .. the PLC will continue to be the industrial work-
horse to well into the foreseeable future.
• There will be new ideas and platforms – the very mention of a non-domain company like Amazon
in this presentation indicates major shifts in the industry. Amazon has propelled itself into this
discussion by embracing the latest technologies in robotics, material handling, vision, AI, Big Data,
Cloud Computing and leveraging them to improve it’s efficiencies – at the same time providing
frameworks and best practices for others to use and benefit.

Relay Control Logic – used for
machine control before PLCs

Origins of the PLC
• 1968 General Motors controller requirements
specification with Design Criteria for a ”standard
machine controller”
– Elimination of costly scrapping of assembly-line relays
during model changeovers
– Replace unreliable electro-mechanical relays
– Reduction of machine downtime related to controls
problems
– Provide for future expansion, it had to be modular
– Should work in an industrial environment

The First PLC
• In 1968 by Mr Richard Morley from Bedford Associates
• Modicon ( Modular Digital Controller ) sold the first
commercial PLC - Modicon084
• 1979 Modbus Industrial Communication network specification

PLC Advantages-1
• Component count and space reduction
• Simplify wiring, reduce failures
• Flexible to easily accommodate changes
• When more than 10 relays are needed, a PLC will be cheaper

PLC Advantages-2
• Communication Interfaces
• Easier to troubleshoot

Compact PLC
Modular PLC
Mitsubishi
Allen Bradley
The Compact PLCs have the PS, CPU, COMM
and IOs in a single unit. It may be extended by
plugging in additional modules
In the Modular PLC the Backplane carries the
power, address and data buses to the modules
installed in the rack.
Modules have separate functionality : PS,
CPU, COMM and IOs
IO Addressing
CPU needs to be configured with the locations and types of IO modules. DIP switches on the IO module
may need to be set to the slot number
Alternatively the CPU may automatically recognize the plugged in module and assign it an address in
continuation from left to right :
-- right most Input card is I0-7 next one is I8-15.. and so on.

Some More Types of PLCs
PLCs with the form factor of a Digital Panel Meter
PLCs are also embedded in HMI and Drives

Siemens PLCs – various ranges
S7-400(H) CPU Hot-standby
with redundant CPU configuration
& event synchronization bus.
Changeover in 100ms max.
Redundant CPUs at max10Km
apart.
Upto 65356 DIOs, 4096 AIOs
Redundancy is enabled by
configuration and no modifications
are required in the PLC program
ET-200 Modular IO with
S7-300/S7-1500 type
CPUs for distributed
computing
Mid-range S7-300(left) is superseded by S7-
1500(right) with modern features for easy IT
integration and networking.
S7-1500 is available in the traditional PLC
hardware format and as a Soft-PLC running
on an IPC platform
Low-end S7-1200 for simple
applications generally stand-
alone

PLC Memory Space
• Divided into
– Program
– Data

IO Addressing
• Input Module: Slot 3 / Channel 1
• Some PLCs enable definition of an alias Tag
Name that is more user understandable

PLC Programming Languages
• IEC 61131-3 Standard specifies features, syntax and semantics that must be supported in
PLC Program structure and programming languages
• Program is structured as Program Organization Units (POU)
– Programs can be configured for
• cyclic execution in configured order ( Prog1, Prog5, Prog2,.. )
• Fixed Interval execution ( Prog3 @ 100ms say)
• Triggered Execution (Prog4 on DI1 )
• Can use Function Blocks and Functions
– Function Blocks
• Instantiated as “local to a POU” or Global and are called by Instance Name ( Counter1 is instance of Counter Function
Block)
• Can use Functions
– Functions
• No retentive memory after return ( Maths, Comparison … ADD, ISEQUAL…)
• Can use other Functions
• Data
– Global Variables are accessible by all Programs
– Local Variables are accessible only in POU where they are declared

Ladder diagram
Structured Text
Instruction list - deprecated
Function block Diagram

PLC Programming Languages –
Some Comments
• IL similar to assembly
• ST similar to a higher level language like C.
– Adv : Good for implementation for Indexing arrays, IF THEN, CASE,
FOR, WHILE constructs and Maths operations
Good for memory management & Communications – open and write to
serial port of TCP socket
– Disadv : No Visualization as in LD.
• LD is similar to an electrical circuit. It uses the same structure as the
relay logic that existed before the invention of the PLC.
– Adv - Can be understood by anyone with basic electrical knowledge.
Software skills are not needed.
– Easy to visualize interlocks, edge detection.
– Disadv : No straight forward implementation for Indexing arrays, CASE,
FOR, WHILE.
• FBD good to visualize signal flow and control loops AI1 went to that
PI1 controller whose output went to that AO1

SFC: Sequential function chart CFC: Continuous Function Chart
SFC used for sequential control system
• A state is typically characterized by the set-points,
logic and outputs.
• When input condition required for a transition is
sensed the system moves to the next state
Example
•Tank Filling State
•Mixing State
•Tank Emptying State
CFC :
• No networks needed.
• Loops can be created.
• Order of execution of blocks can be specified.
• Used in Process Industries, Motion Control, Data Streams

Writing Portable Applications with IEC61131-3
When Porting is required across PLC Families/Vendors use only
Standard IEC61131-3 function blocks

IEC 61131-3 & PLCOpen
• PLCOpen had come up with standards that enables export/import of IEC
61131-3 compliant PLC programs and Function Blocks in XML format
• While most PLC Manufacturers support the IEC 61131-3 Programming
Standard, differences in the underlying hardware and use of specialized
Function Blocks means that programs may not be easily ported from the
PLC of one manufacturer to that of another. On import to another
manufacturer’s editor, the program would require significant rework for
hardware/Function Block specific customization
• The PLCOpen XML Exchange Standard has enabled development of 3rd
party Function Blocks containing Logic for specific functions (eg.
Motion/Robot Interface) that can be imported into the Editors of multiple
PLC vendors (Siemens, Allen Bradley, Mitsubishi, Beckhoff..) and then
configured to connect with the PLC specific IO and Communication
registers. This enables code reuse across PLC systems from different
manufacturers

IPC based PLCs
IPC based PLC system connected to IOs on high speed real time Ethernet Fieldbus
CAT: Control Automation Technology

Windows 32 / 64 bit
Industrial PC System
On Multi-core machines each of the Runtime Processes can be assigned to a separate core
Visual Studio based development environment. Windows based system.

Auto-Code Gen from
Matlab-Simulink
Typically used for process where Fuzzy Logic Control or some complex algorithm is needed – Supported by the TwinCat PC
based PLC System

Siemens Soft PLC – S7-1500 Software Controller
• Industrial PC formats like Panel PC, Rack-mounted PC, Hybrid-PC with backplate for
ET200 modules (effectively making it a PAS – see later slides)
• Siemens hypervisor allocates the PC resources such as
interfaces, processor cores or memory directly and exclusively to the OS and to the
Software Controller. Even an OS crash or restart has no effect whatsoever on the
execution of the control program
• Communication between the OS and the Software Controller
• TCP/IP Communication using S7 blocks
• OPC UA Server for the Software Controller
• ODK1500S Open Development Kit for real-time programming in C/C++
• Communication with Remote I/O and Field Devices over Profibus, Profinet
• Applications : Operation of PLC, HMI, image processing and other software on a single
hardware platform, linking to databases, complex algorithms, Model-based development
with Simulink..

PLC Control of Drive using :
Start/Stop Cmd
Alarm Reset Cmd
Speed Cmd
DO_1
DO_2
AO_1
Ready/Alarm Fb
Run/Stop Fb
Actual Speed Fb
Actual Current Fb
DI_1
DI_2
AI_1
AI_2
DI_1
DI_2
AI_1
DO_1
DO_2
AO_1
AO_2
PLC Drive
• Expensive Analog I/O required
• 11 wires required per Drive
1. I/O 2. Communication
PLC Drive
Control Words
Register1.Bit0 => Start/Stop Cmd
Register1.Bit1 => Alarm Reset Cmd
Regsiter2 => Speed Setpoint
Register3 => Current Limit
Status Words
Register4.Bit0 => Run/Stop Fb
Register4.Bit1 => Ready/Alarm Fb
Register5 => Error Code
Register6 => Actual Speed Fb
Register7 => Actual Current Fb
Cyclic
Read Cmd
Write Cmd
• Only single multi-drop communication cable is
required – greatly reducing cabling cost
• Cable break is detected by Protocol Specific Keep-
Alives OR Pre-set Cyclic Read/Write Cmd intervals – if
R/W Cmd is not received every say 1s then
communication break is assumed and Drive goes to
configured safe state
• Large number of Cmd/Status Signals can be R/W
• Drive can be remote configured using the
communication cable
Comm
Cable
DO_Cmn DI_Cmn
AO_Cmn AI_Cmn
DI_Cmn DO_Cmn
AI_Cmn AO_Cmn

Industrial Protocols
• IEE802.1 Time Sensitive Network (TSN) OSI Level-2 Specification for
deterministic Ethernet Communications.
• Supported Network Infrastructure ( switches / routers..) must be used for TSN.
• Same network can be used for IT and OT
• Protocol used depends on the support by Plant Instruments and PLC

Modbus ASCII Messages
• Master query to Slave at device address 06
• Requests data from 40108 through 40110
– Start Address 0107 (006B hex)
– Number of registers 03
• Slave response 40108(02 2B) 40109(00 00) 40110 (00 063)

Modbus-TCP
Exchanges
Modbus Ethernet Port 502

PLC as Modbus - Master & Slave
Node Modbus
Fnc Code
Device
Start Addr
PLC
Start Addr
Number
of registers
Initiate Modbus
Request
Modbus
Response
Complete
• SCADA is Modbus Master and PLC is Modbus Slave
• PLC registers are mapped to Modbus Registers SCADA
PLC
Drive
Meter
SCADA
SCADA
• PLC is Modbus Master and Field-Device is Modbus Slave
• PLC accesses Field-Device registers using Modbus Functions

Example of Distributed Control

Foundation Fieldbus
• Foundation Fieldbus Example of Distributed Control
• Function blocks can be built into Fieldbus Devices as needed to achieve the desired device
functionality.
– For example,
• a simple temperature transmitter may contain an AI function block.
• A control valve might contain a PID function block as well as the expected AO block.
• Thus, a complete control loop can be built using only a simple transmitter and a control valve
• Function Blocks (FB) provide the control system behavior. The input and output parameters of
Function Blocks can be linked over the Fieldbus.
• The execution of each Function Block is precisely scheduled. There can be many function blocks
in a single User Application.
• Function Block Name Symbol
– Analog Input AI
– Analog Output AO
– Bias/Gain BG
– Control Selector CS
– Discrete Input DI
– Discrete Output DO
– Manual Loader ML
– Proportional/Derivative PD
– Proportional/Integral/Derivative PID
– Ratio RA

Distributed Control Configuration

OPC UA Subscription
Client Server PLC1
10.2.68.1
Create Subscription1 (PLC1@1s)
Subscription1 Handle
Add Subscription1.Item1 (40108)
Item1 Handle
Read Req (10.2.68.1 03 0107)
OPC UA Modbus TCP
Read Res (03 0000)
PLC1
10.2.68.1
Item1 Update (VTQ) [ INITIAL]
Read Res (03 0000)
Read Req (10.2.68.1 03 0107)
Read Res (03 0001)
Read Req (10.2.68.1 03 0107)
Item1 Update (VTQ) [ VALUE CHANGE]
Remove Item1
Delete Subscription1
1s
Polling-Based
Subscription-Based

Supervisory Control
Before the PC/Microprocessor
Line/Diagram of entire plant with indicator lamps and dial guages for process status.
Physical Knobs and Switches for Supervisory Control

SCADA-HMI
• Industrial Panels
• Panel PCs
• Industrial PCs
• Wireless Tablets
• Control Room Multi-monitor PCs
• WebServer (HTML5) for Browser Access using Remote PCs and Cell-phones

SCADA - HMI
Data Entry
Supervisory
Control
Value Display Alarms
Trends

Modern Control Room
with PC based SCADA

Data Logging
Before the PC/Microprocessor
Magnetic Tape Recorder recording – upto 7 channels
with Time and Voice Annotations
Strip Chart Paper Recorder
Up to 24 analogue inputs, 36 digital inputs &
36 digital outputs

Or OPC UA
Server/Client
Data Logging
PLC to Historian using OPC UA Server
Refer Later Slide
for
PLC direct
access to SQL database

Industrial Automation Hierarchy

Industrial Automation Levels
Enterprise
Systems
Plant
Systems
Level 4
MES Level 3
SCADA Level 2
Process Control Level 1
Field Level 0
Data
Plans
Sensors
Batch
Server

Level-3 MES Work Flows
Production Maintenance Quality Inventory
ANSI ISA Standards S88 for process control
S95 for integrating enterprise and control systems
EBR Electronic Batch Records – FDA requirement for pharmaceuticals

Level 3 Standards
• S88
– object-oriented programming to conceptualize batch control
– specifies that the recipe be separated from the process unit or control system where that
recipe would be executed
– shows how the same recipe could be run on different process units, as long as those process
units had comparable processing capabilities.
– The reusability also means that once a “library” of process and recipe models was defined,
writing the actual control code could proceed rapidly from those generic models.
• the basic elements of S88 are as follows:
– a physical model of a manufacturing process, which is a description of what the process
does, and what its capabilities are
– a recipe, which describes the formula (the physical ingredients of a batch) and what actions
are to be taken in what order. The recipe is written as a procedural model, which can be
subdivided into unit procedures, the unit procedures into operations, and the operations into
phases
– the equipment logic, which is the description of how the procedure ( production ) is
implemented
• S95
– identifies the interactions between ERP Layer4 and Process Control Layer3.
– XML Schemas are defined to standardize the data passed between the layers
– defines terminologies and good practises
• Level3 ->what will be produced
• Level0,1,2 -> how will it be produced

Common Resource Management
- Route Management
MES ( Batch) System selects the equipment to be used based on the recipe and other batches scheduled / in progress.
Process Data ( temperature, ph, density, color …. ) is logged for quality control and regulatory bodies

Level-4 ERP
Customer Relationship Management (CRM)
SCM ( Supply Chain Management )
PLM ( Product Life-cycle Management )

Level-5
Value Addition by the IT Industry
Manufacturing Intelligence
Monitoring of Key Performance Indicators
Production, Energy, Inventory.. And other typical “Cloud” Applications

Integrated Workflow
1. Sales force registers enquiry
2. ERP system checks inventory, raw
material order and production lead times
and provides sales with estimated delivery
dates
3. Sales books order in the Sales Module
4. ERP System checks if order can be
fulfilled with
a. Existing finished goods stock
b. Or using existing raw materials
c. Or else places orders for raw materials in
the Purchase Module
5. Once material has been received and
passes Incoming Quality Checks the
Inventory System Raw Material stock is
updated and Accounting Module is
notified to release payments to vendors
6. Based on the availability of raw materials
the ERP system places the Production
Order in the MES execution queue
7. Based on availability of production line the
MES selects the Production Order from
the execution queue
8. MES writes the product type and quantity
to the SCADA system for the production
line that is available
9. SCADA system selects the recipes
corresponding to the product type and writes
the set-points, quantity and quality criteria to
the PLCs / Controllers
10. PLCs execute the production sequences to
produce and test the product
11. PLC/SCADA updates the MES with the
Finished goods produced
12. MES updates the ERP System with Finished
Goods Produced
13. ERP updates the Inventory Module –
Finished Goods Stock
14. ERP system checks Accounting Module for
customer payments received and updates
Dispatch / Delivery Module with the Order
15. After dispatch the ERP system tracks
Accounting module for Payments received
and closes the order
16. ERP generates alerts to the Service Module
at end of warranty period and prompts for
AMC and spare sales
17. ERP alerts the Sales & Service Module on
End-Of-Life Time to push for sales of new
versions. ERP alerts Inventory Module to
dispose unused raw materials / finished
goods that cannot be diverted to other
products

PLC Selection – IO Sizing
• Inputs
– Digital :
• Start
• Stop
– High Speed Digital : Encoder, Pulse
Train
– Analog :
• Raw Juice Tank Level
• Sugar Soln. Tank Level
• Actual Raw Juice Flow Rate
• Actual Sugar Soln. Flow Rate
• Mixing Tank Level
• Mixing TankHigh Speed Digital :
Encoder, Pulse Train
• Temperature
• Outputs
– Digital :
• Raw Juice Valve
• Sugar Soln. Valve
• Mixing Tank Out Level
– High Speed Digital : PWM
– Analog :
• Raw Juice Valve Command
• Actual Sugar Soln. Valve
Command

PLC Selection- considerations
• IO Count
• IO Voltage/Current Levels
• IO Distance – individual cables to the PLC or Remote IO System
• Analog Resolution 8/12/16/32-bit
• Control Algorithms – PID, Math Functions, Timers, Counters
• Process Speed – PLC Scan times and IO read/update rates
• Existing PLC / SCADA installations
• Field Networks, Inter-PLC communication
• Operator Station / HMI
• SCADA
• Industry Regulations : Marine, Safety, Redundancy
• Cost of Programming Software
• Cost of PLC Hardware

PLC Programming - Guidelines
• Establish the Customer’s Requirement
• Identify the different users of the machine
– HMI Roles : Operator, Supervisor, Engineer
• Understand the Upstream and Downstream processes
• Identify Normal Sequence of Operation
• Identify Faults/Safety/Shutdown Operation
• Identify Special features (eg. cold start)
• Identify states of the system
– Identify state entry conditions (Inputs)
– Identify state conditions (Outputs)
– Identify state exit conditions (Inputs)
• Based on IO Lists, HMI Setpoints assign PLC IO and
Memory
– Retentive
– User Access Levels

PLC Programming - Good Practices
• No Backward / Upward Jumps
• No Loops
• Avoid SET / RESET of variables
• Scale and Calculate AIs at the start
• Update PLC outputs at the end
• Logic flow should be downward to enable easy
debug
• Right justify coils
• Identify and handle fault conditions
• Divide your code into sections, functions
• Test the sections of code as you write them
• Test extensively in a safe simulated environment
before plant trials

PLC Programming – System Startup
• Ensure that you are wearing the right PPE and follow the safety processes as per the
work environment
• Ensure that you know of alternate safe escape/evacuation paths and assembly areas
• Ensure that you know about all the movement paths of the system and are in a safe
area while operating the machine.
• Be aware of the other machinery operating near you, wires, pipelines, etc
• Ensure that you know where the Mains Switch, Manual Shut-off Valve is located so
that you can react quickly to an emergency
• During wiring ensure that you follow Mains safety Lock-out/Tag-out procedures
• Before starting plant/machine trails ensure that the system is mechanically,
hydraulically and electrically sound. All mechanical, hydraulic and electrical interlocks
are operational. Mechanical stoppers at the end of strokes, Safety Gate Interlocks…
Hydraulic fittings are secure and there are no leakages, Pressure Relief Valves are
working… Electrical interlocks – Emergency Stop Switches, Safe Torque Off
interlocks on Drives…
• In case of any doubt ensure that you are convinced with the system safety and
received full clarifications before you proceed
• Design the program so that you can operate the system in Manual/Test Mode and
test each movement/operation a low speed and torque/pressure – this must be
verified before full Auto Mode Operation of the System

Debugging Ladder Logic
Why is Y0 not ON?
Back Trace from the Problematic Tag
Examine the Tag’s dependency tree to locate the problem
Example Y0 is not ON as X0 is not ON

PLC Code Quality
• Cyclomatic number v(G) : number of
different paths that can be executed in a
routine
• Essential Complexity ev(G) : number of
different unstructured instructions in a
routine
• Dead Code
• Unused variables
• Comments

PLC Programming - Safety
• Stop buttons should be wired using a normally
closed contact programmed to examine for an on
condition
• Using a normally open contact programmed to
examine for an off condition will produce the
same logic but is not considered to be as safe.

HMI-UI Design is just as Critical !!!
• Logical, readable and in-context presentation of data =>
Information
• Intuitive, follows operator work-flow, logical navigation
with hierarchical content – overview, details, diagnostics
• Clear display of Process State V/s Desired Conditions
• Trend and Status information
• On occurrence of Alarm Conditions guides the Operator
with resolution steps for corrective action
• The Controls ( on screen elements) that the Operator
can use to manipulate the process should be clearly
identifiable
• Role based display – Operator need not see settings
meant for a Commissioning Engineer
• Consistent colors in line with industry standards
• Avoid excessive detail, flashy graphics, animations

PLC Redundancy
Redundancy is enabled by configuration and no modifications are required in the PLC program

Digital IO Redundancy
It is recommended to use
2 sensors for max. availability

Analog IO Redundancy
Both outputs provide half of
the value.
If one of the modules fails,
the active output delivers
the complete value.

Layers of Protection
The Safety Instrumented System (SIS) is the final level after which System Control is beyond the
power of the Control System Engineer and depends on Mechanical / Civil Designs for
containment.

Safety Instrumented System (SIS)
“The process control system affects the size of your paycheck;
the safety control system affects whether or not you will be around to collect it.”
-- Rinard (1990)
Standards : IEC 61511 (ISA 84) for process / plant application
IEC 61508 for devices
Typically Redundant Systems
Ability to self test Inputs and Outputs, by connecting to loop-backs

Safety Instrumented (Interlocked)
System
• The automation strategy is usually simple, for example,
If L123 < L123min; then, reduce fuel to zero
water
LC
PC
fuel
How do we
automate this SIS
when PC is adjusting
the valve?

If L123 < L123min; then, reduce fuel to zero
steam
water
LC
PC
fuel
LS s s
fc fc
15 psig
LS = level switch, note that separate sensor is used
s = solenoid valve (open/closed)
fc = fail closed
Note the “Fail Closed” valves. That fail to a safe state.

SIS
• The SIS saves us from hazards, but can shutdown the
plant for false reasons, e.g., instrument failure.
1 out of 1
must indicate
failure
T100
s
2 out of 3
must indicate
failure
T100
T101
T102
Same variable,
multiple sensors!
s
False
shutdown
Failure
on
demand
5 x 10-3
5 x 10-2
4.2x 10-5 1.0 x 10-4
Better
performance,
more expensive

RISK MATRIX FOR SELECTING
Safety Integrity Level SIL
low moderate high
Event Likelihood
Event
Severity
extensive
serious
minor
Table entries
word = qualitative risk description
number = required safety integrity
level (SIL)
Safety Integrity Levels
(Prob. Of failure on demand)
1 = .01 to .1
2 = .001 to .01
3 = .0001 to .001
Selection
documented for
legal
requirements
Medium
2
Major
3
Major
3
Minimal
1
Medium
2
Major
3
Minimal
1
Minimal
1
Medium
2

Allied Fields
Building Automation

Building Automation Systems
• Protocols : OPC, BACnet, LON, Modbus, SNMP,
KNX, DALI, Zigbee
• BACnet Controllers support
– Node discovery and browsing
– Configuration
• Node, IO
– Programs
• Periodic Functions
• Event Driven Functions
– Time-of-day, Input state
• Access to IO on other nodes for sensing and control

Building Automation Systems
Zoom to see details
• The Web-8000 Series WebController (on the extreme right – in the security block) enables internet access for configuration and
user operation
• During on-line configuration the engineer can browser to discover Controllers on the network. The IO points of one controller can
be referenced by another controller.

Allied Fields
Substation Automation

Substation Automation
• Protocol – IEC 61850. IEC60870, Modbus,
DNP3, ICCP
• Intelligent Electronic Devices (IED) for
control, protection, monitoring, metering
• Specialized hardware rather than general-
purpose PLCs
• Programming – Step-wise with Wizards
and Specialized Function Block Programs

• Bay Controller – IED interface and interlocking, Fast Horizontal Control
• IEDs – Protection and Switching
• Station Computer – Station-Level Control, HMI and Configuration
• Network Control Center Gateway – Enables Remote Control at Grid Level

Siemens Sub-station Automation
Hierarchy

Allied Fields
Telemetry, Telecontrol, Teleservice

RTUs
Remote Terminal Units
• Used for geographically distributed applications
– Oil, Water Pipelines, Canals, Street lights, Traffic Lights
– Electrical Power Grid, Wind/Solar Generation
• Have inherent battery-back-up, redundant power supply options, solar power options,
low power consumption, wide operating temperatures and rugged construction to
survive for extended periods in harsh conditions at remote unmanned locations
• Typically support fewer IO points per node – in the tens
• Historically had limited and simple logic compared to PLC
• Modern RTUs however may support programming using IEC 61131-3 languages like
Ladder, Function Block, STL, SFC
• Communicate with DCS or SCADA base-station using wired or wireless
communication
• Inherent support to communication using wireless technology like 2G, 3G, LTE, 4G,
Radio, Satellite Link
• Support Application Layer protocols like Modbus RTU, DNP3,
• Typically have buffering capacity to store logged data and transmit in bursts to the
base-station
• Network Time Sync of system clock, Local Time Stamping
• Extensive Remote Diagnostics and Control - Modern RTUs may have embedded
Webserver, Email, SMS, File Logging and FTP server

RTU Remote Communications
PLC vs RTU
Modern general-purpose PLCs paired with suitable UPS,
Modems and special environment-proof enclosures
could be used in place of RTUs … but … the RTUs are
built and certified specifically for these applications so
makes sense to use them here.
Some Vendors (Siemens) may use PLC hardware as
RTUs

Wide Range of Networks
Protocols Supported
• Telecontrol Basic
• Sinaut ST7
• IEC 60870-5-101/104
• DNP3

SMS, Email, Radio
Communications can be set-up by
configuration of the Communication
Modules with very little programming
effort

What is a DCS?
• The classic DCS originated from an overall system approach
• A DCS is a complete tightly integrated package from a single vendor consisting of
– Hardware
• Process Controllers, including redundant controllers & IO and other certified safety systems
• Networking - wired, fibre-optic, wireless, mesh, redundant
• Server & PC hardware, including industrial PCs, redundant drive systems, multi-monitor systems
– Software
• Engineering and Configuration Environment with in-built Change Tracking and Audit Trails
• Single Data Model – One data owner – System-wide Tag.
– Example : Tag defined in Process Controller with HMI Alarming, History Logging is immediately available with HMI and
Historian
• Visualization
• Batch Support at Controller-level
• Process Database
• System-wide Modelling and Simulation
• Multiple Process Controllers autonomously control large sections of the plant and they can
inherently communicate with each other.
• The entire system is tested, certified and guaranteed to handle high-speed data
communications between the nodes
• Coordination, synchronization and integrity of process data over a high-performance and
deterministic network are at the core of the DCS architecture
• 20-30 year Vendor guarantee for entire system support

PLC vs DCS
• Historically the DCS was designed for
– integrated control of entire scope of large process plants with millions of IO points
– Guaranteed network performance for communication between the distributed Process
Controllers and also with the HMI, Historian, etc..
– Redundancy and high availability
– Large Number of Analog Control Loops – programmed with Function Blocks
• Standard Function Blocks (PID, etc), Fuzzy Logic, Advanced Algorithms and Visualization
Templates(Refining Column, etc) are available out-of-the-box in the DCS software
• New Function blocks can be created and reused
• Of-course Digital IO is also supported!
• Configured and maintained by Trained Engineers
– Guaranteed fixed interval scan. Example : @0.1s @1s @5s
• Historically the PLC was designed for
– Local control with a few 100 IO points
– Stand-alone operation
– Low Cost and Simplicity
– Relay logic Replacement – programmed with Ladder Logic
• Initial emphasis on simplicity to enable even electricians to understand
– Ladder Logic is continuously executed cyclically
• Fast response guaranteed below the Scan Watchdog Time (say 0.1 ms )
• Fast but non-deterministic scan scheduling interval – sometimes say every 50ns, other times 52 ns…
• Many machines ship with built-in PLCs for their control and may be installed in a plant
that is controlled by a DCS. The DCS may communicate with these PLCs using IO or
a field-bus.

PLC vs DCS
1980
2020
https://realpars.com 1980(expensive), 2020(cheaper)

PLC vs DCS
Today – PLCs come close.. but..
• PLCs today support
– Networking using standard Field Buses (but through-put and reliability may not be guaranteed for your
system configuration)
– Function Block Programming
– Redundancy (but at cost comparable to a DCS)
– Configurable Scan Intervals
– PLC Tag data-base integrated with SCADA of the same vendor (or uploaded to SCADA for a different vendor
– here syncing changes could be an issue)
• Using PLCs, SCADA, Historian… a system comparable to a DCS could be built
• But… using networked PLCs+SCADA as a DCS … is very much a “do-it-yourself” (DIY) approach
with plenty of technical risk as well as added costs that are not always immediately obvious.
• Today due to significant price reduction in DCS systems…it still makes good Engineering and
Economic sense to use a DCS than attempt to “club together” your own system using networked-
PLCs and SCADA
– For distributed systems with large IO counts
– Proven DCS applications – refineries, chemical processes
– Where long support guarantees are required for the system – and individual PLC and SCADA vendors may
not provide 20-30 year support guarantees
• Several DCS Systems of today actually use PLC hardware and SCADA software with some
tweaking. However here the integration is done by the equipment manufacturer and a pre-
packaged system tested and certified for the IO Counts and data-transfer rates is supplied.
Example Siemens PCS7 DCS that uses S7-400 PLCs and WinCC HMI, Rockwell’s ProcesLogix

ABB System 800xA AC800M
-Fully Integrated Enterprise
With System 800xA, users enjoy a fully integrated enterprise where PLCs, DCS systems, safety systems, electrical systems, live
video, maintenance systems, ERPs and more all work together in an seamless environment. The result is improved plant visibility
and fast access to relevant information in real time, allowing operational issues to be resolved before downtime occurs.

Machine Vision Components
• Digital greyscale or color camera to acquire images
• Imager to digitize them
• Processor to run the programmed image analysis
• Input/Output hardware and communication links to report
results and send/receive messages from other devices,
such as an HMI, PLC or Robot.
• Optional components include:
– Object-sensing synchronizing sensor (usually an optical or
magnetic sensor) that triggers the vision system to acquire and
process an image.
– Actuator to reject or sort parts based on the results o f the image
analysis.
• Machine Vision Programming Software

Machine Vision System Programming
• Functions
– Inspection: Presence/Absence, Defect Analysis, Pattern
Matching
– Identification: Colors, Data Codes, Lot Codes, Serial Numbers,
Text
– Measurements: Gauging, Dimensions, Counting, Locating
• Programming a vision system involves the following:
– Teaching the vision system what to look for, based on distinctive
"features of interest" (also known as features) in the image.
– When to take a picture, and how best to illuminate the part.
– How to communicate the results of its analysis, and the actions
to take, based on the results.

PLC communication with the Machine
Vision System - Configuration
PLCs may enable browsing
Cameras on the network and
quick set-up of map between
the Camera parameters and
PLC registers
Communication is over
Ethernet or Serial :
Using Custom Messages
OR Protocols like Modbus,
FTP, SMTP, Ethernet/IP,
Melsec, Profinet, PowerLink

PLC communication with the
Machine Vision System - Runtime
• PLC triggers the Machine Vision System which
captures and processes the image and
generates the results
• Machine Vision System sets PLC register to
indicate completion of image processing
• The results are written to / read by the PLC
system into PLC registers

Siemens S7-1500/ET200 NPU
Neural Processing Unit
• NPU can input data (Camera
images / files) from its USB, Ethernet
ports or the PLC CPU NPU processes
data through its Neural networks and
passes the result to the PLC CPU
• Uses Intel Myriad X AI Accelerator
• Works with NNs designed and
trained with Tensorflow and Caffe ML
Frameworks
• Suitable for Image Processing using
CNN, Audio Processing using RNN
• Applications – Vision controlled
Motion, Sorting, Pick & Place

AI
Configuration
AI Viewer
Data Upload
For Training
& Monitoring
Download
Trained
Model
Training
Inference
Engine
AI-Based Preventive Maintenance
• AI Inference on the PLC Rack
• Inference Engine on the AI Processor analyses Field
Signals from the PLC CPU for patterns that suggest
performance degradation

Access AI Inference functionality from Ladder Logic
Motion
Block
AI
Block
Large number of Input Variables can be monitored and
error conditions can be inferred -Refer the RED dots on
the display
To reduce down-time and operate plant with reduced
efficiency a “new normal” can be selected
The AI – algorithm / Neural Net used is not mentioned in
Omron documentation, but time series data of periodic
nature is monitored for deviations – so can we guess it is
a RNN?

Gravure Printing Process
• All axes in the machine have the same web speed
• The virtual master generates the position and speed set
value as electronic line shaft (ELS) by math and
software, which replaces the mechanical line shaft (MLS)
for synchronization
• The format depending angular reference for the printing
cylinder axes are generated by the local master using
the electronic gear box function

PLC- Position and Motion Systems

Types of PLC Motion System
• Positioning Module ( may be built-in using on-board PLC outputs)
– Pulse output – Open Collector OR Differential, PULSE/SIGN OR CW/CCW
– Upto 8 axes
– Logic in PLC-CPU sequence program
– Operations
• Electronic Gear
• OPR (Original Point Return) Control – Zero Return Control
• Positioning Control (PTP (Point To Point), Path) – Preset Segment Data, Absolute/Incremental
• Modes - Speed Control, Position Control, Speed / Position Control switching, Jog
• Interpolation - Linear, circular, helical - sealant-glue applicator, milling
• Simple Motion Module
– Communications
– Upto 16 axes
– Module has predefined configuration, PLC CPU sequence triggers the execution
– Operations ( supports all Positioning Module Operations )
• Electronic Cam Function
• Synchronous Control - for Printing Lines, Packing Machines, Sheet Metal working
• Speed-Torque Control –Press-Fit Control cap tightening
• Motion Controller (PLC-CPU and Motion Control in the same module)
• Motion Module (separate CPU dedicated for Motion in PLC rack)
– Communications
– Upto 256 axes
– Motion Module is programmed in ST, PLC CPU sequence triggers the execution
– Operations ( supports all Simple Motion Module Operations )
• G-code program execution
• Simplified Robot Control
Electronic Cam / Synchronous control – movements previously used mechanical coupling for coordinated motions
can now be controlled by separate (smaller) motors that are electronically coordinated with no mechanical linkage.

PLC-CPU with Positioning Module
Servo
Amplifier
PLC-CPU
Positioning
Module
PLC-CPU Sequence Logic provides to the
Positioning Module
• Pulse Counts & Frequency
• Calls to pre-configured Position blocks in the
Positioning Module
PLC-CPU Sequence Logic receives from the
Position Module
• Present position – pulse count sent to Servo
Amplifier
• Status and Alarms
Servo
Motor
Sequence
Logic

PLC-CPU
with
Simple
Motion
Module

PLC-CPU
with
Simple
Motion
Module
Motion Operations stored in Tables in the
Simple Motion Module
PLC-CPU triggers the Position Operation
in the Simple Motion Module

PLC-CPU & Motion Controller Communication
Motion CPU executes independently & directly accesses IO - thereby reducing load on the PLC CPU

PLC-CPU and Motion Controller Scans

Servo Amplifiers
• Network Compatible
– synchronous control and interpolation control
by sequential commands
– Built-in Positioning – only the pre-configured
seq no selected by Master
• Point Table
• Program
• Indexer
• Multi-Axis models

Servo-Amplifier Control Loops –
Position, Speed, Torque

Integrated
Software
• Programming
– PLC-CPU, Motion-CPU, Servo
Amplifier
– Assistants for data setting, arc
calculation
– Motion Simulation
– Motion Controller Programming
– Synchronous Parameter setting
– electronic gears, shaft, cams
– Cam data creation
• Start-up and Adjustment
– Monitor & Alarm
– Digital Oscilloscope
– Multi-axis adjustment
– Tuning

A Typical Robot
Teach-
Pendent
Robot-
Mechanics
Robot-
Controller
Commercially available robots have
an optimized set of Kinematic Equations
based on the manufacturer’s
knowledge of their mechanical
Construction.
The Robot Controller has the processor
for calculations and Power Electronics
Motor Drive Hardware to control the
motors

The PLC and The Robot
• The PLC is the Robot
– For simple applications like bang-bang, x-y motion
– Coupled with suitable Drives or Motion Controllers
• The Robot is the PLC
– Application with complex Kinematic calculations but
few IO points can be controlled by only the Robot
Controller using on-board soft-PLC
• The PLC and Robot co-operate together
– For large application with large number of IO points,
the PLC executes the machine logic and co-ordinates
over high-speed communication busses with one or
more robots that execute the Kinematic calculations

Typical Robot Languages
• Kuka Robot Language (KRL)
– Similar to Python

The PLC – Robot Interface
• Siemens TIA - Combines PLC and Robotic
Programming Environments
– Robot’s Teach Pendent is no longer the primary interface with
the robot controller.
– With PLC-based robotic controls, the Human Machine Interface
(HMI) is now the same throughout the system.
– The alarming system, fault recording, data monitoring, and the
other functions that are available to HMI now directly interface
with the robot controller.
– Unique faults and custom operations can be added and changed
directly to the robot controller.
– An HMI interface allows for a much greater application-specific
focus, as well as a considerably more agile structure.
– Robots from multiple vendors can be programmed from the
same PLC programming environment, thereby greatly reducing
engineering effort as there is no need to learn the Robot Specific
Programming Language

PLC –Robot Interface
• The KUKA industrial robot consists of the KUKA KR C4 Robot Controller and the
robot’s mechanical system
• Using the KUKA.PLC mxAutomation block library, the SIMATIC controller controls
the robot.
• The interpreter for the commands of the KUKA.PLC mxAutomation block library, on
the Robot Controller, receives the commands from the SIMATIC controller, computes
kinematic transformations and executes them on the robot’s mechanical system.

• Uniform UI to program and
control Robots from different
vendors and different coordinate
systems
• System can be taught in jog
Mode – using cartesian or axial
co-ordinates
• Both individual Positions and trajectory
curves Paths can be saved

(PLC’s) HMI is used to interact
with the Robot Controller

CNC - Computer Numerical Control
• Evolved from Punch-Card programmed Numerical Controlled (NC) Machines
• CNC Machining Process
– CAD software is used to generate 2-D or 3-D Model of the required product
– CAM software processes the CAD Model
• Based on constraints like
– Part Material and Geometry, Tool Properties, Jig and Fixture Properties
• To generate part-program code for the CNC Machine
– Geometric G-code – Tool Path, Feed Speed..
– Miscellaneous M-code – Coolant, Tool changes
– While maximizing savings of time, material and energy
– CNC machine controller executes the part-program code and together with drives and
motors, controls the various machine axis to move the Tool, Work-piece and other
machine parts to generate the required product
– CNC machine also interacts with I/O, Safety Interlocks, Conveyor lines, Loading
Robots, Part Inspection Systems (Contact/Non-Contact Probes, Cameras,..) using the
built-in PLC

CNC Controller Hardware
Add-on
Machine Control Panel
with Hand-Wheel
Remote I/O
Numerical
Control Extension
Module
NCU – NC Control Unit consists of
1. PLC (integral part of the CNC)
2. NCK (Numerical Control Kernel)
3. CP (Communications Processor)
4. Operator Panel / HMI (TCU+MCP OR PC for integrated CAM support)
5. Drive
6. NX (optional)
7. Remote IO
Thin Client Unit
NCU7 is a specialized PLC S7-
300 with NCK (Nunerical
Control Kernel) that has direct
communication bus access

CNC Controller Main Hardware
• Operator Panel (HMI) & Machine Control Panel (MCP)
– Operator Functions – Start, Stop, Jog using Key and Digital Feed-Wheel
– Parameter Settings
– Part-Program Import, Editing, Test, Collision Detection
– Monitoring & Alarm
– Service and Utility
• NCK
– Part-Program Interpretation
– Interpolation for Position & Speed Set-points
– Position Control – Accl/Dccl, stiffness, etc.. by communicating with the Servo Drives
– sophisticated algorithms in-advance automatically optimize parameters such as machining
rate or damping while taking account of friction and the contours of a workpiece
• PLC
– Machine Logic and Sequencing
– I/O Interlocks can make calls to the NCK to start / stop operations
– Additional Function Blocks & Axis – like Conveyor.., can be called from the NCK
– Interface with Loading Robot

CNC Controller Software
• Machine Manufacturer uses the
Sinumerik S7 Toolbox with the Simatic
Step7 Professional (TIA Portal)
• Machine can be programmed in PLC
programming languages like Ladder, STL,
FBD, SCL(Structured Control Language),
etc
• HMI screens configured using standard
and user controls

PLC Basic Program FBs
Sinumerik Interfaces for Machine Builders

Sinumerik CNC - Machine Builder Process
Machine Builder’s Code
Steps for the Machine Builder
• PLC Basic Program is built by adding
Standard FBs, example Axis, Spindle,.. to the
project depending on the machine Kinematic
Structure, example : milling, turning,… The
PLC Basic Program organizes exchange of
signals of data between the various
components of the NCU – PLC, NCK, HMI,
MCP
• Drive Configuration for Spindle, Axes travel,
interpolation, resolutions,...
• NCK Configuration
• Drive, PLC, HMI, MCP Communications
• Scaling Machine Data
• Parameterization axis, spindle data &
Measurement Systems
• PLC User Project - use subroutines supplied
by the basic program and implement the logic
operations and sequences of the machine

Data Exchange between PLC, NCK, HMI, MCP, Drives
• Cyclic at start of every
cycle of PLC OB1
– PLC to NCK Commands
– NCK to PLC Status
– For Mode Groups,
Channels, Axes/Spindle,
NCK
• Event
– NCK PLC : PLC
functions to be executed as
part of the workpiece
program
– PLC  NCK : PLC request
to NCK ( eg traversal of
auxillary axis )
• Messages
– HMI /MCP   PLC
PLC-NCK User Program Interface

The CNC and The Robot
• The Robot is the CNC
– Example : KUKA.CNC complete software-based CNC implementation for execution
of machine tool code (G-code) directly on the Robot Controller. This turns the robot,
with its accuracy and stiﬀness, into a machining center for path supported
processes. Example : Drilling, Welding…
• The CNC is the Robot
– No separate Robot Controller is required as the NCK is used to calculate the
Robot’s inverse-kinematic equations and control the Robot as a channel of the CNC
– Robot Kinematics are also available for Siemens NX CAM for part-program code
generation
– Sinumerik’s RunMyRobot /DirectControl extension enables programming, control
and diagnostics of the supported Robots (Kuka, Comau, etc..) from the CNC HMI
– Industrial sectors targeted are additive manufacturing, fiber placement, metal-
cutting, carbon fiber-reinforced polymer, and laser machining.
• The CNC and the Robot co-operate together
– CNC’s built-in PLC communicates with the Robot Controller - typically for job part
loading, unloading…

IOs may be assigned to PLC-CPU or CNC-CPU or Robot-CPU
Mitsubishi PLC, CNC, Robot on the same Base

National Instruments Labview PAC
http://www.ni.com/en-in/shop/compactrio.html

PCs … PACs … PLCs
Programmable Automation Controllers
• PACs bridge the gap between PCs and PLCs
• Rugged Industrial Construction
• Real-Time OS
• Multi-processor and Multi-tasking
• Deterministic Scan times for Logic Execution and IO update
• Redundancy as required
• Large Non-volatile memory / SSD to log data. Time stamping in the PAC itself.
• Multiple Network Ports Ethernet, USB, RS485, Field-buses.. Compatible with
Enterprise Networks with High Level Protocol Support like OPC, SQL Database,
MES, ERP & IoT connectivity, Fault-tolerant File System, Batch Process Control,
large number of PID loops and WebServer
• Programming in C, C++ and also Ladder, FB, SFC
• Multi-domain functionality and Multi-discipline Development Platform – Integrated
Tag Database, Sequential Control, Process Control, Robotics and Multi-Axis Motion
Control, Machine Vision, Communications, Intensive Calculations, Statistical Process
Control (SPC), SIL certified modules, Diagnostics, Predictive Maintenance and
Operations Monitoring, Testing and Quality Control
• Open Modular Architecture with support to large number of Digital and Analog IO and
custom extension IO interfaces with user-programmable FPGA interfaced to the
PAC’s data-bus / mapped to the PAC memory.
• In-built display port & visualization capabilities so the logic and HMI is developed in
the same software package

PACs
Schneider Electric’s Modicon M580 Ethernet
ePAC
Opto22 - SNAP PAC
AutomationDirect Productivity 3000 PAC
Advantech APAX-5000 PACs
Parker PAC

PAC vs PLC & PC+SoftPLC
• PLCs are becoming more powerful and feature-rich
• PLC vendors now designate their high-end PLCs as
PACs
• PCs are becoming rugged, compact and can be
configured for real-time support.
• Soft-PLC systems running on Compact PCs could
provide most of the features of a PAC.
• A feature-rich PLC + Compact PC with SCADA,
Databases and customized-applications written in VB,
C++ could also provide most of the features of a PAC.
• PAC required for high-performance applications with
many interfaces

Interface - Motion, Vision, Test Instruments, Data Log
Typical Application of PAC performing all
the below functions
• Vision based Multi-axis Motion Control
• Quality Inspection using Vision, interfaces
with Instruments using GPIB, SCPI, VISA
• SPC
• High-Speed Data-Logging

PLC as an Embedded System Platform
• Embedded Controller based on Mitsubishi iQ PLC system Architecture
• VxWorks RTOS
• C-language programming
• Auto-code Gen from Matlab-Simulink
• Industry Proven and Certified Hardware
– API access to all iQ series PLC hardware and Communication Interfaces
– Multi-processor Mode with -PLC-CPU Motion Controllers, Robot Controllers,
CNC, .. (effectively as a PAS)
– Standard Mitsubishi HMIs can be used (as they can access variables in the
embedded controller)
– Large 16GB+ data storage, High Speed Data Logging, FTP
– PCI expansion bus
• Guaranteed long support cycles

Mitsubishi C-Controller –Embedded Platform

High-Speed Data-Logging
- Local at PLC

Fast Local Data Logging @ 1ms
SCADA/Historian/SQL PC-based logging is typically slower. Refer earlier Historian Slide

Other Features/Advantages of PLC based
Data-Logging
• Used to capture high-speed events
• Logging is set-up using simple configuration
• Trigger based logging
– Only log data near trigger events, thus saving memory space
• Time Synchronization with SNTP Server
– Data across multiple PLC systems can be analyzed for plant-wide issues
• Ability to access and log data from multiple PLCs connected by high-speed
networks
• FTP Transfer to File Server
• Multiple data-formats, Batch/Lot wise logging possible
• Excel File can be used for Report Generation right on the PLC rack

PLC direct access to SQL Database
• Configure SQL Server Security, Authentication, TCP/IP Port, DB Tables..
• Configure Firewalls Exceptions for the configured TCP/IP Port

PLC direct access to SQL Database
1. Import the SQL Library and
Instantiate the FB and Data-Blocks
2. Code STL Functions to “connect” to the
SQL database and “select”, “modify”
or “insert” rows
3. Trigger the SQL Query
4. Query the Database and
confirm that the data is
added

Mitsubishi
MES-Interface IT
Module
1. From the Production Control Database
acquire Target Production Number of
Units, Lot Numbers, Serial Number
Sequence – this is stored in the local
database of the MES-Interface IT
Module
2. As PLC-CPU completes execution
update the date-time of manufacture,
Serial Numbers and quality related
parameters in the Production Control
Database

Using 3rd Party Software
Despite extensive SAP interfaces available for automatic data transfer with the
Industrial Automation System – many IT Departments may conservatively insist
on .csv file load/dump using a programmed SAP GUI Buttons for Import/Export,
where the user controls the data exchange and data is validated as per the SAP
GUI rules similar to manual data entry
High License Costs for additional connectivity software components may also be
the reason

Using SAP Plant Connectivity Component
Modbus,
Connectivity with SAP can be at the PLC, SCADA or MES layer as per the requirement

IoT Applications and Advantages
• Typical Applications
– Log and Analysis of sensor information for preventive
maintenance, productivity optimization and energy efficiency
monitoring
• Advantages of IoT
– Data Aggregation
– Data Storage – huge capacity and redundancy
– Data Analysis, Modeling and Simulation, Optimizations – access
to huge computing power and latest technologies, GPUs, AI
software stacks, floating software licenses on-demand
– Monetization of Data – lower down time, better efficiency,
increased production through-put, improved safety

The IIoT Edge
• Most Industrial Control Applications are
implemented on the Edge
– Latency Sensitive, need quick response
– Economics, cost of moving data that could be
reduced after some processing
– Regulatory, data must be maintained on-site
as per requirement of Regulatory Authorities

Amazon IoT Edge
• AWS Greengrass is a software that extends AWS Cloud capabilities to local
devices, making it possible for those devices to collect and analyze data
closer to the source of information, while also securely communicating with
each other on local networks.
• So, Greengrass is a software that will enable you to perform, in a local
network, basically the same process as if your Things were connected to a
cloud but this time they are connected to a local device.
• This solves the connectivity issue with the cloud servers. If your Greengrass
device loses connection to the cloud, it won’t stop working. It still gather
data from the Things and perform automated actions (that you made before
deploying Greengrass, we will see that later on).
• Once the Greengrass device reconnects to the cloud it can perform updates
to its core and send you back the data it collected when it couldn’t reach the
cloud.
• AWS Greengrass provides the core software that you can install on your
device, an SDK and an API.

AWS Greengrass Service Features
• A lambda runtime that allows you to execute serverless instructions if needed.
• A shadow implementation, this means that a Thing has a JSON file (the shadow)
where all of its parameters/variables are set and can be modified with lambda
functions from the core or from the cloud.
• A message manager, for instance, when the core needs to restart, the Things can still
send messages and the core will save them until the core has restarted again.
• A group management, a group is comprised of the Things and the Greengrass Core.
• A discovery service, it is a service mainly used by the Things to get certificates to
connect to a Greengrass Core.
• An Over-the-air update agent that allows updating one or more Greengrass Cores on
a network at the same time or on predefined schedules. The devices with the
Greengrass core will need to have the WiFi activated for this feature to work.
• Local resources access on the Greengrass Core device if it is needed, the resources
can be anything.
• A machine learning inference, meaning that the training is done on the cloud servers
but the model (the “brain” of the AI) is on the Greengrass device and can perform in
real time what it was trained to do. We have made a use case that uses machine
learning inference, you can find out more at the bottom of this article.
• Since version 1.7, Connectors help you implement reusable business logic, interact
with cloud and local services (including AWS and third-party services), ingest and
process device data, enable device-to-device calls using MQTT topic subscriptions
and user-defined Lambda functions. This module works as packages that you can
deploy on your core without the hassle of learning new APIs or protocols. It’s meant
to make your life easier.

MQTT Protocol for IoT
• Very Simple Protocol ( ~50 page spec)
• Binary Protocol
– Low Bandwidth
– Small Memory Footprint
• Widely Accepted in the IoT world
– Supported by major cloud players like Amazon, Microsoft, IBM
• Reconnection and resending messages possible
• User Authentication with Username & password
• Message can be encrypted using TLS
• Local Message Broker can be used for forwarding to
cloud over SSL, VPN

Beckhoff IIoT Devices
• TF6701 IoT Communication Function Blocks (software)
– Function blocks for MQTT communication from within the PLC
– PLC library "Tc3_JsonXml" to support JSON parsing
• EK9160 IoT Coupler
– Easily and securely push I/O data to AWS IoT
– Easy configuration via integrated website
– Automatic I/O detection
• C6015 | Ultra compact control cabinet Industrial PC
– AWS Greengrass
– AWS Lambda function retrieves process data from machine
– AWS Lambda function publishes aggregated production data

Native MQTT Support by Modern PLCs
Function Blocks
TLS Certificates
The next slide shows
how to manually set-up
a Modbus to MQTT
protocol converter on a
computer acting as an
Edge Node to connect
an older PLC that
supports Modbus
Communications to the
Cloud

Modbus to MQTT Conversion to support older-PLCs

MQTT Client Subscription
Refer the link below for detailed instructions and source code

IIoT Players
• https://aws.amazon.com/greengrass/
• Microsoft Azure IoT Edge
• Google Cloud IoT Edge
• EdgeX Foundry is a Linux Foundation
Project that created an open source edge
computing core.
• Alibaba and Intel are working on a Joint
Edge Computing Platform too.

IoT vs IIoT Suites
from Leading Automation Vendors
• An IoT platform will give you the middleware
• But you’ll still have to..
– physically connect up your machines and sensors
– install and configure a gateway device
– write the code to pull and capture the data streams
– write the code that manages the data and contextualizes it
– write the algorithms that turn that data into useful KPIs
– write the code that displays within a user interface
– develop code and a UI to capture what the operators are doing
• IIoT suites like Siemens Mindsphere, Beckhoff TwinCAT IoT,..
provides pre-packaged Industrial Connectivity, UI and Programming
Applications to enable remote Configuration, Monitoring, Control
and Optimization of Plant Operations that can be deployed on the
AWS, Azure or Google Cloud

TI- PLC Internal Architecture
Digital Communications

TI- PLC Main Processor
• Arm Cortex-M4/M7 for small PLCs
• Arm Cortex-Ax for large PLCs with
multiple communication interfaces

PLC Software Design
- Editors for User Applications
- Embedded Firmware

CODESYS Dev & Run-time
Codesys provides Industry Standard Editors
Codesys generates a runtime binary for PC based system or embedded controller.

Role of Open Source in the PLC /
Industrial Automation Domain
• Limited by
– Stringent Safety, Performance and Liability Requirements, High
Cost, limited access for trails at large installations, proprietary
nature of existing hardware
– Customer Risk Aversion and tendency to order what is proven
from large reputable vendors
– Customer lack of IT Expertise and focus on Production core-
competency
– Educational Institutes treat PLCs as Black-Boxes and do not
focus on how the Industry Standards should be used to design
the underlying hardware and software
• Almost all Open Source hardware offerings are related to
the Arduino(roughly ARM Cortex-M4) and
RasberryPi(ARM Cortex-A) platforms

https://www.openplcproject.com/
http://scada-lts.org/
The PLC Runtime is targeted at RasberryPI devices
with Arduino devices treated as Remote-IO Modbus
Slaves
https://www.industrialshields.com/ https://rapidscada.org/
Contribuciones de nuestros amigos españoles с некоторой помощью от дорогих русских
Contribuições de nossos amigos brasileiros …
PLC based on Arduino
Programmed using Arduino IDE or
Ladder logic using
http://soapboxautomation.com/
Editor may not be IEC61131-3 compliant.
HMI based on TouchberryPi
Programmed using
Contributions from the US https://cq.cx/ladder.pl
Ladder Editor with compiler for ATMega and PIC targets.
Alternatively ANSI C code can be generated and used with the C-Compiler for another hardware target
Alternatively Byte-Code can be generated and used with target specific interpreters
Editor is old with 1990s look and feel and may not be IEC61131-3 compliant. Not Industry-grade, but should
be a good starting point for students
NOTE : The hardware and software mentioned MAY NOT BE 100% free and/or open-source
Some may require significant effort to set-up and use and some are fairly expensive

• Hardware built around RasberryPi Compute Module with Industry certifications
• Software
 OS uses Rasbian with real-time patch for kernel
 Supports CodeSys Editor and CodeSys Control Runtime
 Supports logi.Cad3 Editor and logi.RTS Runtime
 SpiderControl WebHMI
IoT Support
• IPC with PAS-type capability
The RevolutionPi eco-system
Beiträge unserer österreichischen freunde https://www.controllino.biz/
PLC based on Arduino
Programmed using Arduino IDE or
Ladder logic using https://www.logicals.com/en/
https://revolution.kunbus.com/

CNC Freeware
• http://linuxcnc.org/ LinuxCNC (formerly Enhanced Machine Controller or EMC2) implements numerical
control capability using general purpose computers to control CNC machines

Robot Freeware
• https://www.ros.org/ The Robot Operating System (ROS) is a flexible
framework for writing robot software. It is a collection of tools,
libraries, and conventions that aim to simplify the task of creating
complex and robust robot behavior across a wide variety of robotic
platforms.
• https://rosindustrial.org/ to solve the issue that despite billions of
dollars of research by governments and academia, new robotic
applications were not being introduced in the industry due to
incompatibility between the research and the industrial robotic
platforms

Stuxnet… Worm, Trojan, Virus
• State sponsored Cyber Weapon specifically targeted Iranian Uranium refining
centrifuges
– Delivery Introduced into the computer networks of several Iranian Industrial Automation
companies by USB pen-drives “found” near the organizations
• Spread through the company networks using multiple “zero-day exploits” on vulnerabilities in RPC,
Printer sharing on Windows PCs and replicated itself on all USB pen-drives used on the networks
• Jumped the “air-gap” to the isolated Industrial Control System network (ICS n/w) at the Iranian Natanz
Nuclear Facility on a USB pen-drive and replicated across the Natanz ICS n/w
• On PCs with Siemens PCS7 (DCS) & Step7 Programming Software used an unchanged “Default
Password” that gave Admin access to install/replace a .dll file using a genuine (but stolen)
authentication key
– Payload Scanned the PLC program for certain key parameters example “164” => typical
centrifuges in a cascade and configured Profibus network for Control Valves & Motor Control
Drives
• Updated the Controller Program when Step7 connected to S7-400/S7-300 Controller Hardware
• At pre-programmed intervals every around 2 weeks
– Varied gas pressure to over-pressurize a centrifuge stage
– varied the set-speed of the drives drastically taking them near their critical resonance speeds
• The Controller could continue to report correct Gas Pressure & Drive Speed values to the SCADA so
there would be no automatic shutdown by safety routines or chance for manual intervention from the
Control Room or post-mortem troubleshooting when analyzing logged process data. The durations of
the injected malfunctions were short so as to increase wear and tear on the motor and mechanical
systems but not cause immediate catastrophic destruction
• The slow delayed action – an event every 2 weeks
– made problem isolation difficult
– could destroy even replacement hardware
– caused frustration and loss of morale among the project team
– Effect
• 2000 centrifuges around 1/5th of the total installation were destroyed and had to be completely replaced
• Stuxnet presents a text-book methodology of “Attack Engineering”

Core Functional Components of the Siemens SIMATIC PCS 7 Control System
• A cyber-physical attack involves three layers and
their domain-specific vulnerabilities:
 IT layer which is used to spread the
malware – exploiting
 Control system layer which is used to
manipulate (but not disrupt) process control
 Physical layer where the actual damage is
created

Industrial Cyber Security
• Open communication and the increased networking of production
systems involve not only huge opportunities, but also high risks
• Effects of a Cyber attack on Industrial system
– Safety
– Quality
– Uptime
– Espionage
– Ultimately resulting in revenue loss
• IEC 62443 International Industrial Security Standard
Cisco Industrial Security Appliance ISA 3000
-Firewall & N/w Security Policies

Layered Security
• Plant security
– Protection against access by unauthorized persons – fenced zones based on roles
– Physical access protection for critical components – locked cabinets
• Network security
– Controlled interfaces between the office and plant networks, e.g., using firewalls, DMZ
– Segmentation of the plant network ( could be using vLANs )
• Group on need-to-communicate basis
• Group Legacy systems / out-dated OS
• Groups behind VPN, Firewalls
– Network Monitoring – traffic density, intrusion, blocking of devices attempting to flood the
network at port / segment level
– Secure IT Functions
• Enable Encrypted Communications where possible
• Web-Access using encrypted protocols, VPN, IPSec, HTTPS, MQTT over TLS, FTPS, NTP(secured),
Secure SNMP
• System integrity
– Use of antivirus software with regular updates of virus signatures
– Only “Whitelisted” programs are allowed to execute on PCs
– Maintenance and update processes
– User authentication for machine or plant operators – use Windows Users, Policies –
password life
– Device authentication by passwords and certificates
– Integrated access protection mechanisms in automation components
– Disable unused ports Ethernet/USB/Fieldbus/ WLAN/Bluetooth..
– Accept messages only from known sources
– Disable unused functions Webserver, FTP..
– PLC program locking, function block locking, upload prevention, Audit Trails

Siemens Industrial Security
• Industrial Grade Networking
Security Modules – Firewall,
VPN
• PLC Communication
Processors can also act as
Firewalls

Strategic Role of
Industrial Automation

Machining for Nuclear, Weapon Systems
• CAD/CAM for design and analysis
• CNC machining for parts of weapon systems
• Additive manufacturing for composites – aircraft
wings, rotor blades, composite armour..

SINAVY Automation controls and monitors all vessel systems, including
diesel engines, gas turbines, gear levels, clutches, water jet pumps,
exhaust systems and fuel cells.
It also handles auxillary modules, such as fuel supply and distribution,
ventilation, and fire alarm systems.
It offers a variety of expansion possibilities, including battle damage
control, cruiserange calculation, central battery and pier monitoring
Control of Military Platforms

Dual Use Technology
• From food processing, automobiles, steel,
cement, chemicals, refineries nation-wide utility
grids, to nuclear, weapons, ammunition,
warships…
• PLCs and allied Industrial Automation fields can
be applied to manufacture and control of military
systems
• Nations that invest in the developing
competency and expertise in research, design,
development, production and operation of the
these technologies ensure self-reliance in
industrial and military systems

References
• Technical Documents of Equipment
Manufacturers and Industry Standards
• Books referred are mentioned in the
presentation

From Small to Strategic
You now see the Bigger Picture
All the Very Best in Your Automation Endeavors
Stay Safe!
Thank You
For Questions and Suggestions leave a comment OR contact me via LinkedIn, ResearchGate, Academia

plc8-200417125816.pdf

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