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Published by ratnaji, 2017-01-11 04:33:15

Digital Fundamentals

Digital Fundamentals


In the age of Cellular technology, Android, Windows, E banking, E wallet, E share market, MCX,
Online Ticketing, Decision making, Whats-app, Twitter, you-tube, ERP, email, SCADA, PDF,
XLS,XML, online tendering vendor, order, supplies, taxation, salaries, insurance, CCTV, Access
control etc it is highly recommended to understand the Digital world we live in. Computers are
processing data (Servers) in railways, industries (petrochemical, refinery, power, pipeline),
defence, Airlines, medical, RTO, Passport, etc.
Today’s world exists as shown In the picture below: Corporate, industries, Governments. Here are
some basics of it for common man to understand the world they live in.

We use almost all available technology to run the business or company or to interact with internal
and external stakeholders. We are using, LAN/WAN –OFC, SCADA, RTU, PLC, CCTV, access control,
F&S devices, different hardware and software, routers, copper cable. Each has its complex features,
design, data formats, speed, integration and approach.
Why we need to read this POCKET BOOK on DIGITAL? Data in form of Process is capture thru
sensors in analog or direct digital (thru Copper cable) or wireless mode by Control room
equipment (PLC/DCS/Computers/ Controllers and displays). These signals are routed to another
PLC/DCS or controller or RTU. RTU is routing the data to SCADA (thru OFC 9 on E1). Other form of
data handling is ERP (enterprise resource planning)- Brand -SAP (FICO, HRIS, PM, MII, C&P,GMS,
marketing) , Email, Internet, intranet (HSE,O&M,MIS, statutory, IA, risk), DCC (XLS, Doc, Pdf, ppt,
JPG) CCTV, Access control etc.
Do you find it too technical? Or difficult? The answer it is rather very easy and 80% of
information technology, knowhow, is available for officers to learn first-hand as all GAIL location
has CCTV, Access control, LAN/WAN/ OFC, SCADA, ERP, F&S system. We all can learn. Only we
need a teacher to provide break up of it. Make a block diagram of it with OS, Software, PC Name,
domain, IP, Connectivity, frequency, packet type, register etc;
It’s EASY? – Let’s look it this way, You as a citizen exist as DATA as Aadhar card, pan card, License,
Ration card, Bank a/c, Mobile, RFID, finger print, DNA etc; but our Domain is the Surname or nick
name or Indian/State, caste, gender etc;
You live with a specific surname, nick name, address, all above data. For a post or communication
to reach you need choose to destination, mode, address, language (protocol), voice (sound waves),

post (hardcopy mail) or telegraph (Morse code sounds), handwriting (fonts) in old/stone age days
(Light, sound, smoke signals) etc; similarly now in age of electronics the data, voice, video, picture,
files, medical, process all is sent thru electronic media. Using register (addresses), mode (binary
coded DC voltage, serial coded, optical coded – OFC and Wireless EMW) in digital form. It needs
hardware to translate code, decode, and interpret. Nowadays any data picked as file or process
data is processed into digital form, polled (pulled or pushed) by computer using OFC, EMW,
Ethernet, bandwidth, protocol, channel, hardwire, software, OS, Bits, Binary, Gateway,
converters, router, Screen, Server, Client, Drivers, programming etc;

What is SCADA? – Supervisory control and Data acquisition. It supervises the process and system
(alarms, log book, diagnostics, trends, history, reports (daily, hourly, shift), events) by acquiring
data from connected resources on given network – Serial or Ethernet or OFC (PLC, Sensors other
computer). It is a software (many OEM customized) which sits on a platform (Windows etc).
SCADA/HMI- Data is reflected in pictorial form for the process operator to keep track of operation
and act or control or start/stop. SCADA is purchased keeping in mind the inputs and outputs tage
or points it is supposed to handle. It has library of commands, actions, controls pictures, script algo

What is ODBC? In computing, Open Database Connectivity (ODBC) is a standard application
programming interface (API) for accessing database management systems (DBMS). Any ODBC-
compliant application can access any DBMS for which a driver is installed. Drivers exist for all
major DBMSs, many other data sources like book systems and Microsoft Excel, and even for text
or comma-separated values (CSV) files.

What is OPC? The value of OPC is that it is an open standard, which means lower costs for
manufacturers and more options for users. Hardware manufacturers need only provide a single
OPC server for their devices to communicate with any OPC client.

What is Master/Slave- The server which ask the data is Master, which provided or acts on the
data is slave. Each master can have many slave with different ID but on same protocol, baud rate,

What is Baud rate? The baud rate is the rate at which information is transferred in a
communication channel. In the serial port context, "9600 baud" means that the serial port is
capable of transferring a maximum of 9600 bits per second. the bit rate measures the number of
bits transmitted per second, whereas the baud rate measures the number of symbols transmitted
per second – and that is the major difference between the two.

What Is Parity? In general, parity is the quality of being even or odd. In computer science, a
parity check, also referred to as a Vertical Redundancy Check (VRC), is a method of searching
data for errors. This is done either during transmission or on a storage mechanism, by setting a
parity bit to an even or odd number. For example, if a binary stream contains an even amount of
"1's" and the parity bit is odd, the computer would produce an error because the data is corrupted.
The image shows an 8-bit binary number with a ninth parity bit attached. IMPORTANT: For the
devices connected on same network the Parity and baud rate should necessarily be same.

What is DATA? In form of PDF, XLS, raw data from Sensors in field (pr, temp, flow, vibration,
voltage, current, level, speed, commands to operate SOV, valves (open Close), pumps compressor,
engine (start/stop) etc)) , Manual data in form of passport, RTO, SAP, applications, FICO, HRIS, etc.
It is 4-20ma form, serial register form needs to be picked by wire or wireless mode.

What is Register? Register is like postal address of a data residing/stored in chip in slave
equipment (flow computer, level, pressure, vibration, PC, etc). The Register can be 5 or 6 digit. It
can be float, integer etc. It can be 8,16,32,64 bit long, short or swap data. To test first poll it.

What is ADC/DAC- ADC is analog to digital converter, All current, voltage, frequency (level, pr,
flow data is converted by a Filter, chopper and comparator – IC based hardware system) into
digital wisdom in binary. The reverse is DAC that is Digital to analog.

What is addressable system? It is again like a postal system whereby by configuration an ID is
allotted to an equipment where you know this ID denotes this equipment, converter, sensor, gate,
etc. If the Internet is like a phone book, and a web page is like a physical building, the URL would
be the precise street address of that building. The IP address would be like the car that travels to
its destination.

What is Protocol? Read more about MODBUS, DNP 3.0, IEC etc;
Modbus and DNP are both byte-oriented protocols. Modbus is an application layer protocol, while
DNP contains Application and Data Link Layers, with a pseudo-transport layer.
Both protocols are widely used over a variety of physical layers, including RS-232, RS-422, RS-485,
and TCP/IP. Modbus has a separate specification for use over TCP/IP (Modbus-TCP). With DNP,
the protocol is simply encapsulated within TCP/IP.

What is Redundancy ? This is required to system to switch from primary mode to secondary
mode in case of failure of link/route/OFC/tower/network without data or system loss and the
system must be synchronised in real time. Redundancy can be on LAN or WAN. (Like DRI centre in
GAIL- Noida & Jaipur)

What is Binary ? ON/OFF (1 or 0)- light on –off, voltage (24/110 VDC- on/off ), This is notation
which the machine in fact understands anything you type or read or write or visualized. For
PAYTM or Xerox – black/white is -1/0), Colors on screen (HD- DTH) in digital is coded as 1/0.
Barcode on paperback books or general store items. Also as pixels.

What is Serial Communication- RS 232 , RS 485? RS 232 is 3 wire serial communications but
cannot be multi-dropped and can be used for short distance only. RS 485 is 1.2 km 2 (half) wire or
4 wire(Full) duplex system with D+ & D- terminology. Upto 32 devices with different slave ID can
be connected on 1 RS 485 in daisy chain. Baud rate & parity of entire loop to be necessarily kept
same. Bunch of data flowing in frames or packet with recognition bits, carrying information data in
binary coded

For example (of data storage ID and register) - Passport (consider it as equipment number)

holding many value (information) much as name, Date Of Birth, place, Mother Name, Father name,
address, experience, place. This is like registers where value (like Pressure, temp , K factor, Flow
rate, Total, Range, density ) is stored in a flow computer. This value is pulled (read) by a software
(PLC /SCADA/RTU) thru RS232/RS485/Profibus/ hart/ wireless or any other medium (Copper/
ID Addresses: fundamentals : a)Subnet must on same Ethernet (TCP/IP) should necessarily be
same ( b)Domain numerical should be same 172. *.*.* Or 192.168.5.*domain is
like a family (sur name) / domains entity. c)How data is do fast? Basically if a travel in lightning
speed is any medium that is 3x105 Km /Sec. d)Packets have data frame / structure – PC/software –
have encrypted code to decode / deciper meaningful data of the frame. Who is sending the frame
(email / PDF/SCADA/ Intranet / internet) who is asking (Defense, banking, share market etc)

Software can on it’s own picks up the ID’s & decode. Server – store , monitor, route, control, protect
back up data/information. Server – need protect in and uses firewall, antivirus, back up,
redundancy, Reboot, batches, synchronization and passwords. Servers & client need to have
master / slave similar software OS/Platforms to be compatible and working in unison.

RS 485 Connectivity Concepts ( Flow meter, UPS, Energy meter, Solar Inverters, AI converter)
actually in use : Protocol- Modbus, Baud rate – 9600,Parity None,2 wire, Slave ID 1,2,3,4 – Up to 44
Devices, Register type – Holding, Input, coil, Input coil. ,Data type – 16 & 32 bits, Float, integer,
swap, long swap, Address- 5 or 6 Digit type. Double , single. String, calculated etc;

Connector in use in communication: D- 9 pin, RJ 45- 8 pin, D 25 pin, OFC- SC connector, C
Connector. Cable Unshielded twisted pair (UTP) CAT-5 is rated to 100 Mhz ,CAT-5e is rated to 350
Mhz,CAT-6 and CAT6e is rated to 550 Mhz or 1000 Mhz depending on your source , CAT-7 is rated
to 700 Mhz or 1000 Mhz. 10BASE-T is the IEEE standard that defines the requirement for sending
information at 10 Mbps. 100BASE-T is the IEEE standard that defines the requirement for sending
information at 100 Mbps ,1000BASE-T (also called gigabit Ethernet) is the IEEE standard that
defines the requirement for sending information at 1000 Mbps on unshielded twisted-pair cabling,
and defines various aspects of running baseband Ethernet on this cabling.

What is Gateway or Converter- Converters has RS 485 input (say Modbus ) but give out virtual
comport RS 232 output (set ID, comport, parity, baud rate) on IP address based connectivity.
Gateway does the same but the configuration is directly ID (configurable) based.

Types – Serial RS 232 to Serial RS 485, RS232/422/485 to Ethernet or to OFC converter/ Gateway,
master/slave etc;

What is RTU – Remote Telemetry unit- Metering or process of data from a distance (Telepathy,
telecom etc) thru on different speed and protocol. Process digital data available from PLC. It has
time stamping, can be configured for multiple interfaces RS 232/485/Ethernet and also change to
optional Protocol.

What is PLC? A device having programmable control logic with maths, algorithms, control,
commands. It helps in programming Logic, Controller algo, alarms, events, sequence, timer, lead,
lag, cascade, batching, sub routine, emergency etc; it has diagnostic capability to tell failures. Why
Logic programming is done is PLC? Data processing and execution is PLC is faster. It is easy,
fast, duplication of tags also easy.

RS32 is like only 1 person can call you & vice versa (bidirectional). Rs485 1PC (Master) can poll
(Call) many slave ID (IED – Intelligent Electronic device) – Maximum 32 on 1 Loop in Daisy Chain.
OFC – is simply a transparent medium (like river or highway) to allow all kind of data / file /video
transmission in optical form (after multiplexing). EMW – Electromagnetic waves (requires No
Medium) to travel carries data / file/video thru waves in a ) line of sight b)Troposphere c)
Satellite thru cell phone / Internet, radio etc.
What is Ethernet? Ethernet is a family of computer networking technologies commonly used in
local area networks (LANs) and metropolitan area networks (MANs).

Packets: Email / PM module / ISO / Intranet / internet photo / process data / MIS / APPS
software all in DATA form is moving in EMW or OFC or copper medium. Of 4, 8,16,32,64 bit size
with LSB, MSB, defined frame, parity, baud rate, modulation type etc;

What is E1 – 1 E1 is 2 MBPS (megabytes per sec – frequency of binary bytes transmission, 1 byte =
8 bits (word)). One STM-1 is 155.55 and one E1 is 2.048 if we just divide 155.55 by 2.048 we get
75.9 E1s which is not correct. the thing is that we are dividing in decimal where one kilo is 1000

but but when we say kilo byte then this kilo is 1024(binary) not 1000. That’s why we get less E1s
and that is 63. E1 is a band width. Each E1 show carry all the above packets together thru
different from of MULTIPLEXING methods.

What is Platform or Operating system- Windows, Macintosh, Linux, Android etc;

What is network medium? RS232, RS 485, Cellular, UHF, Copper, Wireless (EMW- IR, UH), OFC

What is OFC- a simple special fibre carrying light burst (multiplexed and binary coded) with total
internal reflection and bare losses over very long distances and secure.

What is STM 1,4,16 ? Synchronous transport module SDH is a transport hierarchy based on
multiples of 155.52 Mbit/s. The basic unit of SDH is STM-1.Different SDH rates are given as a)STM-
1 = 155.520 Mbit/s. b)STM-4 = 622.080 Mbit/s c) STM-16 = 2,488.320 Mbit/s (~2.5
Gbit/s).d)STM-64 = 9,953.280 Mbit/s (~10 Gbit/s).Each rate is an exact multiple of the lower rate,
therefore the hierarchy is synchronous.

What is bandwidth? Synchronous Digital Hierarchy (SDH) originates from Synchronous Optical
Network (SONET) in the US. It includes capabilities for bandwidth on demand and is also made up
of multiples of E1. STM-1 (155Mb/s) is 63 x E1, STM-4 (622Mb/s) is 4 x STM-1 and STM-16
(2.5Gb/s) is 4 x STM-4. Check you Mobile box to learn the 2G/3G/4G/LTE bands

What is wavelength- It is inversely proportional to the Frequency. If frequency is more
wavelength is short. In radio we know more by short wave (SW), medium wave (MW) – remember
VIVIDH BHARTI- frequency..

Submarine – travel under water & uses VLF (very low frequency) band. Cruise / guided / laser –
missile / drone / ships uses heat / leaser / Rader / GPS to move in to pre-determined guidance
while moving.

What is modem – modulation / demodulation? Modems are referred to as an asynchronous
device, meaning that the device transmits data in an intermittent stream of small packets. Once
received, the receiving system then takes the data in the packets and reassembles it into a form the
computer can represents how an asynchronous transmission would be transmitted over a
phone line. In asynchronous communication, one byte (eight bits) is transferred within one packet,
which is equivalent to one character. Start 1 bit, 8 bit data, stop 1 bit-it forms a 1 packet of 10 bit.

What is sampling / sampling frequency? To convert an analog signal into Digital a DC chopper
circuit (gates & IC, transistors) is used to chop/sample the analog signal into meaningful Digital
binary (1-0) decimal coded data

What is wireless? – Electromagnetic signal transmission without requirement of medium (like in
sound, we require air) GPRS, VHF, S band, UHF. Signal works in different troposphere strata across
the universe.

What is LAN/WAN? Local area network, Wide area Network.

What is Router, Hub, or Switch?- 10/100Mbps Ethernet and GigE services. A) Hubs and switches
connect computers to create a LAN. B) Switches, unlike hubs, know which device the information
is intended for and sends it there. C) Routers on the other hand can send packets between LANs,
while also assigning IP addresses, acting as a switch and protecting your LAN.

What is Domain? An Internet Protocol, or IP, address is different than a domain name. The IP
address is an actual set of numerical instructions. It communicates exact information about the

address in a way that is useful to the computer but makes no sense to humans. The domain name
functions as a link to the IP address. Links do not contain actual information, but they do point to
the place where the IP address information resides.

What is HART/PROFIBUS/Field BUS? Patented protocol or data structures by OEM’s.

What is realtime? For data to be understood, it is really important to register or know the time
and date of happening. Hence all systems are synchronised thru common server clocks in real-time
that is the system time on all items connected on common network. Nowadays PSP On/Off Survey,
taxi service, GPS, all in real time and location track etc

What is cyber security? Prevent from Trojan, malware, spyware, hacking, attack, theft, failures,
wrong entry, wrong support, etc;

What is line of sight communication? Most of the wireless communication works in line of sight
(as you see straight)angle, that is if a big building, mountain etc comes in its path of
communication the signal will bounce and die or may break or may not reach at all.

What is reflected from troposphere? DTH, VHF, UHF signals are electromagnetic beams directed
towards sky and comes back after bouncing or redirected by satellite. These signals have different
wavelength are category. Extends upto 8 Km in earth atmospheric strata . Radar, surface to air, air
to air etc;

What is Firewall? What is Antivirus?- it is software to prevent computers from attack of
spyware, malware, Trojans, bugs compatible to existing OS based in PC.They both deal with your
computer’s security. A firewall is like the moat and drawbridge around the castle of your computer
or network. It basically monitors traffic going in and out of the network and stops suspicious
traffic from entering or leaving. There are two main kinds of firewalls, software and hardware
(nowadays routers). If the firewall is the moat and drawbridge, then antivirus software is the
castle guard of your computer. It makes sure that the data found and executed within your
computer is not a known virus. Antivirus software can only track down malicious data that it
knows about.

What is Single mode or multi-mode? Multimode fiber optic cable has a large diametric core that
allows multiple modes of light to propagate. Because of this, the number of light reflections created
as the light passes through the core increases, creating the ability for more data to pass through at
a given time. Single Mode fiber optic cable has a small diametric core that allows only one mode of
light to propagate. Because of this, the number of light reflections created as the light passes
through the core decreases, lowering attenuation and creating the ability for the signal to travel
further. This application is typically used in long distance, higher bandwidth

What is GSM/GPRS/VPN/-A virtual private network (VPN) consists of the hardware, software
and connections needed to support protected client-server network communications over public
network infrastructure via a method called tunnelling. GPRS technology, General Packet Radio
Service, provides the basic GSM upgrade technology used to provide packet data at up to 172 kbps.
GPRS and GSM are able to operate alongside one another on the same network, and using the same
base stations. General Packet Radio Services (GPRS) is a packet-based wireless communication
service that promises data rates from 56 up to 114 Kbps and continuous connection to the Internet
for mobile phone and computer users. GSM cellular technology uses 200 kHz RF channels.
These are time division multiplexed to enable up to eight users to access each carrier. In this way it
is a TDMA / FDMA system.

What is Numerical relays? A common term nowadays used in electrical switch gear or Switch
yard. These relays are now programmable and have serial interface with Under/over
voltage/Current, differential relay, earth fault, multiple combination etc;

Communication protocol – It’s Something like Languages and dialect, unless the same is clear, no
data, or voice can be interpreted by the computer or machine( If one speaks in Hindi and other
speaks in Chinese how communication is possible) In telecommunications, a communication
protocol is a system of rules that allow two or more entities of a communications system to
transmit information via any kind of variation of a physical quantity. These are the rules or
standard that defines the syntax, semantics and synchronization of communication and possible
error recovery methods. Protocols may be implemented by hardware, software, or a combination
of both.

Types Of protocol:The Internet Protocol is used in concert with other protocols within the
Internet protocol suite, notable components of which include: a) Transmission Control Protocol
(TCP) b) User Datagram Protocol (UDP) c) Internet Control Message Protocol (ICMP) d)Hypertext
Transfer Protocol (HTTP) e)Post Office Protocol (POP) f)File Transfer Protocol (FTP) g) Internet
Message Access Protocol (IMAP)

Most network equipment features Mbps speed ratings. Examples include; home Internet
connections can range from low values like 1 Mbps up to 100 Mbps and even higher in some
cases.802.11g Wi-Fi connections rate at 54 Mbps. Older Ethernet connections rate at 100 Mbps
.802.11n Wi-Fi connections rate at 150 Mbps, 300 Mbps and higher increments.

What Is DNS? DNS stands for Domain Name System. It’s basically a directory for the Internet that
matches up domain names with IP address. Every single website has its own IP address on the
web, and computers can connect to other computers via the Internet and look up websites using
their IP address.
Imagine yourself in a mall and how the mall is controlled ?- Smoke system, AC, Water,
washroom, multiple lift, parking, lighting, security, motion, CCTV, access control wardrobe, ID etc;
or similarly in hospital, airport, Railways etc; etc; IT IS INTERESTING, isn’t it?
Suggested Home work : Find out the following in your area of working
1. Make a block diagram, Make architecture. Note type of topology, hierarchy, security, mode
2. Define hardware (PC, PLC, DCS, screen, cards, adapters, converters, switch, connectors, cables,

router, hub, CCTV, Access control, VoIP, Analyzers etc). Synchronizing, redundancy, failure
mode. Master/ Slave mode, power supply, voltages. Installation.
3. Define software & licenses, Security. (OS, Custom Software, gateway Drivers, patches,
registers, port type, firewall, antivirus, file type etc) . Compatibility and back up.
4. Domain IP Addresses of the network- (Server & client both)PLC, DCS, Internet, email, CCTV,
Access control, Slave ID of all connected devices,
5. Driver – Baud rate, parity, addresses etc
6. Medium – EMW, OFC, Copper cable, VPN, GSM, GPRS
7. Bandwidth applicable or used
8. Data/ Protocol/speed ,Type
9. Source/resource targeted - /input/outputs- Where the data is coming or going to.
10. List of hardware and software tools, Test software drivers,
11. Finally after learning aim, design, make, test, implement again learn updates.

Suggestions are welcome:
Kishore Singhal



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