Wednesday, October 24, 2018

System-on-Chip - SoC - IP

When a product has to be made small, the board real estate is limited or it has to be manufactured in large numbers.... SoC is the Answer. A Microprocessor evolved into a Microcontroller by packing many external chips into one chip. Now uC Card along with the other blocks like A-D, Port Drivers, Networking elements, Display Driver and other peripherals can be packed into one chip.

Some Power Supply and RF blocks cannot be easily added inside as they have a silicon processing more specific to their applications. Laser trimmed Instrumentation Op-Amps, high accuracy resistor arrays, high value capacitors, magnetics and supporting chips are placed outside on the PCB.

The SOC can pack Digital Chips, Memory, A/D, D/A converters, uC, RAM and Custom programmable areas. For more specialized communications, analog and power requirements; Special SoC types can tackle RF and Power management within a chip because of proprietary silicon processing expertise.

System on a chip - Wiki

"A system on a chip or system on chip (SoC or SOC) is an integrated circuit (IC) that integrates all components of a computer or other electronic system into a single chip. It may contain digital, analog, mixed-signal, and often radio-frequency functions—all on a single chip substrate. A typical application is in the area of embedded systems."

System-on-Chip - SoC - IP

Programmable SoC offers an alternative to custom ASIC as you can make different products from the same chip, yet make products that are portable and low power. The software, pcb, user interface and support components has to be redesigned for every unique product. Many standard IPs are available for Design and Reuse.


Saturday, October 20, 2018

Design Notes - Schematic and PCB - 04

PCB Thermal Design Care for Analog Circuit Stability - If you have a hot power chip near a DC analog circuit, the values will drift, take time to stabilize, this happens even if you use 1% MFR 100ppm. The impact is more if the heatsink is not used and vents and coolers are absent,

So in a PCB keep distance between heating power circuits and sensitive analog circuits, some times PCB tracks will carry heat to the Analog area, Hence keep sensitive analog circuits as plugin modules.

Design Notes - Schematic and PCB - 04

When you make a PCB try to orient all ICs in one direction, so also all diode and cap polarities, then it is easy to populate the parts, easy to verify and troubleshoot for production and testing.
High Frequency and RF Design of PCB
  • Sharp bends in PCB tracks or wires will radiate away the RF energy, so do not have hairpin bends.
  • RF or near RF multilayer PCB have 2 layers as ground plane and tracks in the layer in between, Faraday cage.
Schematic Design Basics
  • When we draw circuits we have to keep in mind the readability, the circuit should be laid out, according to the signal flow, the input output ports shown in the periphery of circuit.
  • Drawing a neat circuit diagram will ensure a better design, lesser parts means greater reliability, simple solutions.
    How To Draw Schematic Diagrams 

    A well-drawn schematic makes it easy to understand how a circuit works and aids in troubleshooting; a poor schematic only creates confusion.
      Product Design Mockup and Prototypes
      • Make a 3D mockup of the final product, both the box and the PCB with components before PCB done.
      • The product with the PCbs, transformer and other panel components should fit in the box it was intended for, or the cabinet that was designed for the Product. To make sure make a Mock-up Product - 3D and display. Even if you have all documents and drawings in place.
      • Make sure of IC pin numbers, size and packages and indicate in circuit like 40 pin dip before going to PCB. Also check every EDA symbol in your software with the company datasheet to make double sure.
      • Do not mix mechanical and electrical connections, these leads to failures and frequent need of repairs and service.
      • When using a double or multi layer pcb make one layer a ground plane, all decoupling caps ground linked to it.
      • Reinforce copper tracks on PCB with a copper wire when it needs to carry more current, tinning may improve a bit.

      Friday, October 05, 2018

      Production Notes - Prototype Fabrication - 03

      Prototype Fabrication and Pilot Production are the first stages of a design concept taking a real tangible form. The transition from R&D to Manufacturing Engineering happens here.

      alpha-numeric LCD based on the twisted nematic field-effect

      Early prototype of an alpha-numeric LCD based on the twisted nematic field-effect as realized in the laboratories of the Central Research Laboratories of F. Hoffmann-La Roche Ltd. by Martin Schadt and Wolfgang Helfrich, photo by courtesy of M. Schadt.

      Sometimes a component can be defective, may not be what it is labeled or may be of a wrong value. In manufacturing 100% incoming inspection of components can catch these errors, Before Assembly of prototypes just test all passive and active components with a DMM and put all ICs in bases, then troubleshooting is easy.
      • When you make your prototype check diode and el-cap polarity, check pin 1 of chips and connectors, resistor values, dry solder and loose contacts, hairline cuts or shorts, e-b-c etc. of Transistors, FETs and thyristors.
      • Observe color code in wires. positive is red and negative is black and green is earth and See Wire Color Code.
      • When you are soldering or cutting leads, room should have cross ventilation, protective glasses for eyes and a good stand.
      • When using a sharp blade the cutting stroke must move away from you and make sure nobody is close, Wear protective or even plain glasses, If you use a blade with the stroke moving towards your body it will cut badly.
      • Power tools and machinery must be used only after exhaustive training and with safety precautions. The power tools used carelessly and wrongly can cause an injury which will last a lifetime or may even handicap you.
      • Have a lathe lamp or table lamp with a 40W edison-filament lamp (ordinary bulb) on your workbench.
      • Have an antistatic mat on the work or test table, if you cannot afford or get it then get a large aluminum sheet, laminate it with an insulating polycarbonate sheet and earth the metal plate with two 1M resistors in series.
      • Use thin multi strand teflon wires for your jumpers within a PCB, these are not damaged by your iron too.
      • Silicone shrink sleeves can withstand high temperature and use this in your work to make it safer and neat.
      • When you make a connection with a wire you need mechanical strain relief or on use connection will open.
      Soldering and Desoldering Tips

      Use the soldering iron as a heat transfer tool, heat the junction of the lead of the component and the copper pad on pcb then touch the hot junction with a flux cored soldering lead wire, it should melt and form a concave shining joint.

      If air bubbles are formed or you see dull convex joints, then it means you have a dry solder and bad contact. Leads of old components due to exposure to moisture, brine or sunshine will corrode, store them well cool-dry-clean-air. Anyway scratch them with a blade and solder them with extra flux.

      When you are desoldering a double sided pcb, use a desoldering pump or desoldering wick. Heat a joint to be desoldered and then quickly tap it hard on the table, the molten lead will fall off.

      delabs Notes from 90s

      Thursday, July 26, 2018

      Learning Science to Promote Scientific Thinking

      Here are some resources of Science, i found useful. Latest news on science, technology, hard science subjects of physics, space and earth science, electronics, nanotechnology and technology in general.

      Museums are virtual Universities. 3D Scaled Interactive Scientific and Engineering Demonstrations in Tech Museums Inspire, Educate and Train many students on Science and Technology Subjects.

      Learning Science to Promote Scientific Thinking

      Such Live Interactive Demonstrations may be very useful for Maths and Economics as well. These are Subtle and Complex Sciences which need Gross Manifests or Exhibits to help youngsters grasp Ideas and Concepts easily.

      PhysOrg - science and tech news
      Publishing around 100 articles every business day, PhysOrg offers the most comprehensive sci-tech news coverage on the web. PhysOrg exclusive feature stories are original and not found elsewhere on the web.

      Multimedia Physics - SchulPhysik
      Physics and Physlets. Astronomy - planet, space weather, cosmos. Mathematics - algebra to statistics. Optics and electrical. Geophysics, Energy, Galileo.

      Mike's Electric Stuff is an Online Electrical Vintage Tour, back in time.

      Flinn Scientific - Science Activities - Sells educational science supplies. Site has especially useful information on lab safety and lab design.  Physical Science Activities - Exciting experiments which illustrate important scientific concepts and are exciting for both you and your students

      National Science Digital Library - NSDL was established by the National Science Foundation (NSF) in 2000 as an online library which directs users to exemplary resources for science, technology, engineering, and mathematics (STEM) education and research.

      Wednesday, July 18, 2018

      Electrochemistry Encyclopedia

      This site contains popular-science style articles describing many aspects of electrochemistry. New articles are added at irregular intervals, and all articles are periodically updated as recent developments occur in the field.

      Electrochemistry Encyclopedia
      • Anodizing - Robert S Alwitt
      • Brine electrolysis - Tilak V. Bommaraju and Paul J. Orosz
      • Corrosion inhibition - Norman Hackerman
      • Dielectrics - William D. Brown, Dennis Hess, Vimal Desai, and M. Jamal Deen
      • Electric fish, electric organ discharges, and electroreception - Theodore H. Bullock
      • Electrochemical engineering - Richard C. Alkire and Thomas W. Chapman
      • Electrochemical machining - Joseph McGeough
      Electrolytic Capacitors - Electrolytic capacitors are capacitors in which one or both of the "plates" is a non-metallic conductive substance, an electrolyte.

      Electrolytic Capacitors

      Extractive metallurgy

      "Metal sulfide flotation concentrates can be treated in a number of ways. These include using pyrometallurgy, or smelting at high temperature, in which process the sulfur in the metal sulfide is oxidized with air or oxygen to sulfur dioxide, and molten metal is produced."

      Electrochemistry is the branch of physical chemistry that studies the relationship between electricity, as a measurable and quantitative phenomenon, and identifiable chemical change, with either electricity considered an outcome of a particular chemical change or vice ver


      Materials-Science of which Chemical/Electrochemical Engineering is a part; is behind all the development of electronic components and manufacturing. The Backbone is Applied Science. A Super Capacitor or a Special RF Semiconductor can only be developed using the research and efforts of these scientists.

      The Sciences or their study has been much nurtured and supported by some countries like the USA. This is the foundation on which many other Technologies like Electronics and Computing thrive. In many other countries this is many times not even perceived as its is not 'glamorous' and requires much efforts and dedication.

      "If the Foundation of Applied Sciences is sound, the Building of Technology is Sturdy"

      As said by - Elektrick Power Jedi - Charge Minds with Electricity - delabs Notes

      Friday, July 13, 2018

      Production Notes - Electromechanical - 01

      Production, especially prototype testing and Pilot Production exposes lot of engineering and serviceability issues. When you mass produce, it is more streamlined, yet the scope for improvement never ends. The process should always be open to feedback and improvements. - delabs

      Practical Electronics at Wikibooks - Nice page to learn basics before you study my points down below.

      Practical Electronics at Wikibooks
      Other essentials include a small pair of needle-nose pliers, side-cutting pliers, stainless steel or nickel-plated tweezers, wire strippers, a hobby knife with replaceable blades (e.g., X-Acto), and an analogue or digital multimeter with test leads.
      delabs Experience - Points to Note
      • The tracks or components on a PCB should not be near the mounting holes, the tracks may form electrical connections with the cabinet earth if they touch the pillar, washer or nut-bolt.
      • When you tighten the screws-nuts-bolt, limit torque by feeling or with torque limit screwdrivers, or thread will slip or PCB-Cabinet break, or CRT-Glass-Plastic will crack-shatter.
      • After assembly and testing is over on a board, do not drill-file it, it should have been done before. Else components crack or tracks break or small metal pieces will form shorts.
      • The Mechanical and electro-mechanical must be streamlined before production, for example when fitting the board the screwdriver may slip and break a zener. The product should be engineered in such a way that it fits easily and the testing and quality checks need not be repeated.
      • Some mechanical failures may not be visible but may show up as a field failure after even 3 months. this will make you lose further orders and ruin the reputation. Hence engineering is vital.
      • Alumina-Aluminum oxide powder mixed in epoxy resin (araldite) can make thermally conductive insulating filler, heatsinks. The Alumina must be free of moisture and very dry.
      • When you drive nails into walls ensure that that part of the wall is free of mains, telephone or any wiring.
      • Some pcbs can have hairline cuts or hairline shorts which will make troubleshooting difficult.
      • Never put or remove ICs, cards or plug-in modules when the power to that system is on, power off system wait for some time for caps to discharge, then insert ICs or cards, applies to PCs too, USB and Firewire ports are exceptions as they are hotplug, anyway even in this, take a bit of care.
      • Use RTV (room temperature vulcanizing) silicone rubber compound or Varnish on PCB-devices to avoid corrosion-dust. more so in industrial environment, ships and chemical industries.
      • Whenever you use nuts and bolts to fasten a PCB or parts to a cabinet use a spring washer, double nut or adhesive to prevent slip. When a loose nut falls on the pcb or transformer sparks will fly.
      • Do not mix mechanical and electrical connections, these leads to failures and frequent need of repairs and service.
      Tutorials on Basics and Instrumentation - Theory must be studied once and referred to, again and again as you do practicals. One is by building DIY projects and then modifying them. Also Repair of equipment, troubleshooting, testing and calibrating.

      Monday, June 25, 2018

      Facts of EMI and RFI from the Inside

      Electromagnetic interference (or EMI, also called radio-frequency interference or RFI when in radio frequency) is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source.

      Electromagnetic interference Wiki

      Vertical polarized VHF- UHF biconical antenna

      Vertical polarized VHF- UHF biconical antenna
      170 – 1100 MHz with omni directional H-plane pattern

      Who would know better about Radio Frequency Interference and ElectroMagnetic Interference more than the Hams or Amateur Radio Community.

      If they have to communicate effectively using limited resources, they have to deal with EMI/RFI effectively, While they build their equipment or combat Noise from other Machines and Installations nearby.

      This problem needs more practical involvement and experimentation to learn, compared to learning something like Digital Electronics.

      Equipment and Electricals like SMPS, AC/DC Drives, Motors, Solenoids and CFL Lamps are to be built/reinforced for low EMI/RFI emission/radiation.

      Radio Frequency Interference (RFI)

      Sensitive Medical Equipment like ECG or even a Aircraft can be seriously affected by Noise.

      Friday, June 15, 2018

      Design Notes - Analog and Opamps - 01

      Analog is the first thing in electronics. Valve Radios had Amplifiers and RF sections that were analog. Even the first computing methods are analog. Analog is close to Real Life parameter behavior. 

      LM335 and LM336 -

      LM335 is a temp sensor, LM335 . use it for temp for CJC. Temperature Sensors - RTDs and Thermocouples in  Temperature Measurement.

      LM336-2.5 is an voltage Reference. precision 2.5V shunt regulator diodes, Applied as a precision 2.5V low voltage reference for digital voltmeters, power supplies or in opamp signal conditioning.

      Current Loop -

      4-20 ma will drive DC drives, motors and steam valves. It is a current loop, for long distance transmission, current loop is not prone to noise and hum, EMI RFI. As it is a small power transmission no loss of data, also many equipments can be in one data loop. A single transmitter with 4-20mA out can drive a strip-chart recorder, motor, controller and SCADA input. all in a series loop. Current loop is like 4-20 mA

      Opamp Notes and Types
      • TL062, LF353, TL072, fet input. 1 tera ohm input imp.
      • OP07 higher price, 1 giga ohm. 75uV offset.
      • LF353 pin to pin replacement of TL062-72 and 82.
      • LM358 works on single supply too, low price, inp imp 1 meg.
      • LM324 Quad, works of batteries well.
      • All work best with dual +/- 5 V or more. LM7805 -LM 7905.
      Analog Electronics: Basic Circuits of Operational Amplifiers

      Examine the operation of the following circuits of operational amplifiers: inverting amplifier, summing amplifier, difference amplifier, differentiator, and integrator.

      Remembering Bob Pease

      Remembering Bob Pease

      Points to Note -
      • Analog ground (opamps), digital ground (CMOS) and power ground (relays and LED) should be separate, (linked at root)
      • Glass epoxy PCB have high insulation resistance, above 10 tera ohms, and are not hygroscopic which means they do not drink water vapor, this makes them very suitable for precision instrumentation and sensitive circuits.
      • When you measure DC levels in 16bit accuracy or more you need resistors which have temp. coeff. of 10ppm, or you may have to put the entire circuit in a stable 45 deg oven. Thermoelectric effects, EMI, RFI, pA Leakage currents, ground loops, contact resistance all can make the readings drift and unusable.
      • High impedance points of circuit like 500 kilo ohm and above can pick up AC noise and DC leakage currents. this will affect the performance of circuit, so for DC you have to put a guard ring of the signal ground around that point in PCB. For RF you have to shield with things related to iron and mu metal, for low signals even a copper shield will do.
      • Percentage and ppm: when percentage becomes like 0.001% it is difficult to manage, so we use ppm-parts per million.5% means 5 parts in 100 parts. 23 ppm means 23 parts per million parts. 0.001% - shift the dp-decimal point four places to right it is 10ppm. 0.01% is 100ppm which is the variation of value of mfr resistors on temperature change.
      Learn this at my Industrial Process Control Circuits

      Thursday, June 14, 2018

      Lightning Bolt damages Components

      A ThunderBolt Zap can damage electronic parts. The Earth Leakage Circuit Breaker ELCB or Overload Breaker may Trip.

      Surge Protection and Lightning Arrestors

      Mains Strip Board should have protection, The EMI RFI filter, Varistors can help. Earthing and Lightning Arrestors should be good in the building.

      The Blue ones are MOV Metal Oxide Varistors, sometimes they fail as a short circuit, so better to use a fast blow fuse. Then you see Gas Tube Arrestors that are even used in a Landline Terminal Box.

      Surge Arrestors

      A Surge Arrester is a device to protect electrical equipment from over-voltage transients caused by external (lightning) or internal (switching) events. Also called a surge protection device (SPD) or transient voltage surge suppressor (TVSS),

      Line-Filter - A special class of capacitor is used in power-line (mains) filters.  Line filtering is a very tough application for a capacitor.

      Achieving EMC for Dc-Dc Convertors - DC-DC converters, whether they be an off the shelf brick design or a discrete equivalent, are a source of EMI (Electromagnetic Interference). EMI is unwanted electromagnetic energy that propagates by radiation and conduction over system signal and power lines.

      SMPS switch mode power supply design, PSpice simulation - These definitions should be considered relevant to a SMPS, and may not apply identically to other technical areas.

      Friday, May 11, 2018

      Instrumentation and Automation - 01

      Here are some Test and measurement notes. These ideas come from practical experience. But the jots are not in any order but are quite important.

      DuMont Lab Oscilloscope

      Scope Notes
      • If the waveform on the scope droops then you may need to use a 10X attenuating probe or mode. this attenuator is at the tip of the probe hence better measurement possible, also very high frequency signals may be best transmitted over a 50 ohm impedance matched line to the Oscilloscope. 
      • Karl Ferdinand Braun - In 1897 he built the first cathode-ray tube...oscilloscope. CRT technology is to this day used by most television sets and computer monitors. The CRT is still called the "Braun tube".
      • Do not use an oscilloscope to measure 230V directly, use a transformer, differential probe or attenuator.
      • An oscilloscope 1M probe or a DMM 10M impedance can load circuits with nano-pico amps of bias.

      DMM Notes
      • Test a NPN transistor, DMM in 200K range. emitter negative probe, collector positive probe, it should show open. while still holding that way press wet finger on base and collector, it may show some reading, then it is ok. for PNP swap probes polarity and do the same thing. the wet finger when pressed applies a base current in uA.
      • The most common reason of DMM failure is when a person tries to measure 230V AC with a DMM in current or ohms mode, with the probes in the wrong sockets. Use external attenuators and shunts.
      • A DMM in diode mode or resistance mode can be used to test IR diodes, take it under 100W lamp and measure, cover the IR diode and measure you will see a response in proper polarity.
      • If you put the DMM in 2V mode and measure the voltage across a ordinary LED near a 40W lamp you will see around 200mV. Turn off 40W lamp the mV will fall near 0. Even metal-can transistors with their top ground away will become photo sensors.
      • When you measure low voltages or high resistance like 1M with a DMM your body must not be in contact with the probe tips. Body resistance is low in comparison so error in reading or loading of mV from sensor, in sensitive and high impedance ranges.
      • Red socket and probe for positive and black socket and probe for negative
      • Is it oscillating ?.... We cannot say, it could also be DC, you need to see if a Clock is present. use a signal tracer or a DMM freq mode, or AC measurement. or build this solorb.com-elect-logprobe. When you do not have a scope you can build one for the PC.
      • Polarity and Zero Cross indicators tell you to swap the leads. Use a comparator or opamp to build it.

      Monday, May 07, 2018

      Multi Zone Process Monitor

      Here is an ancestor of the product in the earlier post. It is a Process Scanner and Indicator. There was no control, but there were individual alarms for each channel.

      Multi Zone Process Monitor

      This is a original design of mine, obsolete now due to size and technology. The inspiration of the product concept was from a Omega Catalog Item. Even today i use the Omega catalog for inspiration, but i do not design complete products, only circuit sections.

      Read more about Control Instruments at my pages here

      Thursday, May 03, 2018

      EE and Computer Online Learning - MIT

      Free Online Course Materials for EE and Computers. Here are resources useful for the EE Students and Teachers. These are at MIT and they are available for all. It is a OpenCourseWare (free).

      Electrical Engineering and Computer Science at MIT

      "MIT has awarded electrical engineering degrees for nearly 130 years, and our educational programs have been at the cutting edge since their inception. We provide an in-depth education in engineering principles built on mathematics, computation, and the physical and life sciences, and encourage our students to apply what they learn through projects, internships, and research. "

      EE and Computer Online Learning - MIT

      delabs Notes

      Students can enhance their learning even at home after the classes using these materials. This will help you grasp what happens in the college the next day.

      It is also important to keep yourself physically fit. Some jogging, swimming, cycling and light workout will even strengthen the nervous system.

      I would not like to write this here, but i have to. My own experience. Do not build muscles for looks or abnormal growths. Some use hormones, over exercise and even some medicines for artificial growth. At a later age it causes lot of problems due to accelerated aging. Even athletes should refrain from these for the long term interest of their health.

      Wednesday, April 18, 2018

      Ergonomics and Safety of the Workplace

      Ergonomics and Manpower the Engine of Growth -  A Worker in One Firm is a Customer for another Firm. Healthy and Safe Workers implies a strengthening Consumer base.Just imagine what wonders it can do for the economy, when you broaden your view, think togetherness, as a Whole; not in isolated competitive groups, not in parts.

      Ergonomics reduces Worker Stress. Helps in keeping good Mental and Physical Health. Safety is very important. His Limbs, Eyes and Ears are assets that a firm hires.

      Ergonomics and Safety of the Workplace

      A good Manager knows that Manpower is the Foremost Asset of any Company.
      First Aid and Flame Resistant Uniforms

      Tools and Apparel to make workplace safe. First Aid and Safety, Fire Protection and Flame Resistant Clothing. Cleanrooms  are very important for Microelectronics, MEMS and Precision Instrumentation.

      In spite of "Prevention better than cure", a worker can get injured, more so on the field, where preventive measures may not be in place. A Portable First Aid Kit that should be in Service and Commissioning Departments. A stitch in time saves nine. in reference to: "Your employees may require first aid at remote worksites, too."

      Worker Safety and Health Education

      When we educate ourselves about a Hazard, that awareness is the first step of defense. Resources like this should have a Kids Section. Just like Nasa and Fcc have. We have to catch them young, Interactive tutors and Activities will prepare them for a Safe and Sensible future. Home, Garden, Transport and School are also like a Workpace.

      Kids of recent generations are degrading intellectually, it is more so in the developed countries. Education has to be emphasized, Hobby DIY activities encouraged. Hardships simulated, so they become responsible Young Citizens.

      Rockefeller Jr. (A Philanthropist) was brought up with such discipline, he was not allowed entertainment when he was young. His father the richest man in the US at that time.

      Resource for Workers and Employers. CDC - Workplace Safety and Health

      Intrinsic Safety and Zener Barriers

      Designing and Building Intrinsically safe Industrial Systems is of paramount importance as Human Safety is involved. Even in Switching Loads some contactors, relays, circuit breakers and motors are hazards as some sparking becomes inevitable.

      Intrinsic Safety - Omega.com

      Solid State Relays are safer but on an overload even these can pose a fire hazard if a HRC fuse is not used. Sensor measurements must employ low voltages and currents. Even cabling management and hermetically sealed enclosures may be required when volatile fluids are close by.

      delabs Notes - 2002 -2005

      Thursday, April 05, 2018

      Two Setpoint Temperature Controller

      A Two Point Process Controller or Temperature Controller would look like this. When a High-Low Alarm Protection for uC based Controller was needed the same was modified and used.

      Sometimes uC based instruments just forget and that can be costly, the watchdog timer has solved this problem. In Industrial Process Control we cannot take any chances, so a two tier or even three tier protection is required, especially so if the Job or Raw material being processed is expensive. So Real Time Analog Trip + uC Controller is safe. Then you can still have Electro Mechanical Devices for Extra protection against Fire or Meltdown.

      Temperature is the most common process parameter, Pressure seems to be next. Flow, Level, RPM, Distance and many more follow.

      Two Setpoint Temperature Controller

      When a physical parameter let us say distance is measured, we first need a sensor that converts it into electrical values, digital or analog. The sensor used for length is a Linear encoder and it creates the electrical information for the DRO to Display.

      Now many sensors like a strain gauge produce very low and weak signals and some are non-linear. So the signals undergo Amplifying, Temperature compensation and Linearizing together called Signal Conditioning. This stage outputs some standard values like 4-20mA, 0-10 V, 1-5V, or even directly digital or wireless in the new technologies. Even when a digital interfacing standard is used, amplification and some signal conditioning is required at sensor end. Compensation and Linearizing can be better done with a uC using Math or Look up Tables.

      When you have many different parameters then it is better to use process controllers with a 4-20mA input standard. Then the inventory of controllers can be reused for any process.

      It is always better to use sensor-end transmitters to get 4-20mA to your Controller, Recorder or SCADA System.Weak signals are corrupted by noise and dont travel long wire distance. Junction EMF at joints and terminal blocks add to errors. These are overcome by the 4-20mA signal that has the juice and punch to transmit the data over the shop floor to the control panel rooms.

      Read more here Temperature Measurement and Control

      Sunday, April 01, 2018

      Safe and Sound - Product Safety

      Caution is better than Risk, Prevention is better than cure. using the the right tools for a job alone is not sufficient; You have to get trained and informed about its proper use and safety precautions.

      When we Design a Product or Develop further a design; we have to integrate Product Safety into the usage method and improve usability and safety. Product also has to be Engineered in such a way that manufacturing it does not pose hazard to the worker.

      Safe and Sound - Product Safety

      Product Safety
      • Product should not give even the lightest shock, Even metal parts on user side to be laminated.
      • High energy circuits never enters analog and digital circuit areas without Opto or other Isolation.
      • Gadgets, Furniture, Tools and Storage Units should not cause injury. Rounded Edges, Non Toxic.
      • LED and Lasers can damage Vision, welding too. Use Protective Filter Glasses. After a comment by John Bump
      Worker Safety
      • Helmet, Goggles and Face/Respiratory Mask when working with power tools/ abrasion and large objects.
      • Crepe Bandage, Neoprene Ankle/Knee/Thigh Support when pushing or pulling or Physical Exertion.
      • Waist/Back Support Belts and Straps to reinforce back/spine while doing Heavy Lifting or Movement.
      • Waistband Thick Belt or Traditional Sash helps Posture and prevents slipped disc or spinal injury.
      • When using a Knife, Sharp Tool, Pointed Tool or Drill; cut/bore away from your body or finger/leg not towards.
      • Use Long Riding Leather/Synthetic Boots when working in chemical plants and heavy industry.
      • Cross Ventilation and exhaust fans important if even little chemical fumes are generated in your work.
      • Soldering, plastic forming and even for some kinds of material processing. Good Ventilation or Masks needed.

      Friday, March 23, 2018

      Wiley InterScience - Technical Content

      Introduced in 1997 and launched commercially in January 1999, Wiley InterScience is a leading international resource for quality content promoting discovery across the spectrum of scientific, technical, medical and professional endeavors.

      Wiley InterScience - Technical Content

      Enhanced Tools to Discover Relevant Content: Comprehensive search engine optimization ensures easy discoverability of content, delivering relevant and immediate results to users.

      Wiley InterScience - Technical Content

      Industrial Engineering

      Subjects like robotics, Engineering Management, Industrial Reference Books and Manufacturing Engineering. Includes Plastics, Metals and Mechanical Engineering aspects.

      Electrical & Electronics Engineering

      The topics here are Electronics and Communications, Reliability, Testing Technology, Industrial Electronics, Process Control Methods, Lighting and Power Supplies too,

      CrossRef - Connect users to primary research content, by enabling publishers to work collectively.
      CrossRef is an independent membership association, founded and directed by publishers. CrossRef's mandate is to connect users to primary research content, by enabling publishers to work collectively.

      Wednesday, March 21, 2018

      80C31 and 8052 Microcontroller

      8048 and MCS-48 made designing with Microprocessors easy with built in I/O ports, RAM and Timer. The I/O ports for the 8085 was an external 8255. 8749 enabled users to burn and test firmware on an integrated UV Eprom.

      80C51-52 which came out as the fully evolved uC had built in Serial Ports UART and more Math, better Timer-Counter and Interrupt Handling. The 'C' is for CMOS that made handheld instruments possible due to low battery usage and lesser support chips.

      Here is a kit from Bipom that may help you learn more about the basics of embedded systems with a SBC,

       MicroTRAK Bipom 51-E Complete

      MicroTRAK Bipom 51-E Complete

      MicroTRAK/51-E Complete includes MicroTRAK Carrier Board, MINI-MAX/51-E Microcontroller Board with Ethernet, TB-1 Training Board, MMC-RTC-1 board with Real-Time Clock and 128MB Multimedia Card (MMC), 8051 I/O Module

      The Assembly Code MCS-51 set is used to program the chip. There is a 8052 Basic that can understand the Basic Language, useful for people who are not comfortable with mnemonics.

      Now we have 8051 chips with EE Flash and some have a watchdog and I2C too.

      80C51, SBC, Firmware and Circuits

      80C51 Single Board Computer SBC and Firmware Code. Interface 8051 or 8052 to PC on a RS-232 or serial port. Microcontroller Board and learn about MCS-51.

      delabs circuits - micro1

      Saturday, March 17, 2018

      LED Lighting and LED Lamp Drivers

      LED Lighting is gradually replacing CFL Lamps because they are more frugal in drawing energy and last many years. These have been around for some years and the technology is progressing. Now LEDs which show the illuminated objects in their true colors (like sunlight) are also coming. Due to the green initiatives of many countries, people have become aware and also implementing these solutions. These become a necessity when you start using Solar Panels for Home Power.

      LED Lighting at delabs Tech

      LED Lighting and LED Lamp Drivers

      The CFL lamps have reduced the use of the Filament Bulb due to lower power consumption. Now LED lamps may have to replace CFL but it is progressing. Few years ago only Conference Rooms, Media Events or Product Exhibits could afford the LED lighting, it was a Novelty. Now LEDs are affordable and Reliable Driver Solutions are also available.

      The problem like in most Tech Learning Curves is now the SMPS drivers for these LED Arrays. The LEDs are reliable, but drive systems are still having problems. Cost effective drive systems from make affordable lighting possible. But due to Quality and Reliability issues, system integrators face implementation problems.

      When Mitutoyo the maker of the Best Metric Tools started decades ago, it faced a tough market. In those days, Japanese Goods were known as cheap and low quality in Europe and America.

      Companies like Mitutoyo, Sony, Misubishi, Hitachi and many more changed the scenario completely. Now Japan is a Symbol of High Quality and New technology Innovations. Other countries should follow this Golden Example set by Japan and its Products. Every new firm has to go thru those Stages.

      A genuine long term commitment to R&D and Quality will build the reputation of Brands, Firms and entire Regions. Anyway, here are some nice resources to help build Drivers and Systems for LED Lighting.

      Learn how to make drivers at delabs Power Electronics Section

      These Semiconductors and Applications are Excellent, the driver systems have to be engineered and perfected by manufacturing and development. A casual or quick results method will backfire. Hence system integrators start by working closely with the vendor (Vendor Development) of Drive Systems. Finally deliver only systems that are Robust and Burnt in. The other option, work with know friendly customers as a Beta Testing and learning phase, till systems reliable for global deliveries.

      Monday, February 26, 2018

      Control system design Notes

      Proportional Controllers not only save energy, they can give a controlled finish or treatment to a job. An on-off controller or thermostat limit protection has to be used in series, this is to to stop a Runaway Process.

      Control system design Notes

      There was a real life instance when a Temperature cycling oven maker (environment chamber), faced large liabilities as an 8086 based profile controller and chart recorder just locked up and all the electronic equipment were roasted. Here even a bimetallic thermostat would have saved the day. Nowadays we have a watchdog timer to prevent such uP mishaps, but still use an analog controller in series as an over temperature trip.

      Other Reading

      The basics of control system design: Part 1 - Moving beyond PID

      "This series of six articles will explore the use of six variations of P, I, and D gains: Proportional Control, Proportional-Integral Control, Psueodo-derivative feedback with feed-forwared (PDFF), PID control, PID+ control, and Proportional Derivative Control."

      Sunday, February 25, 2018

      Blind Dial Analog Temperature Controller

      This is a Low cost controller, Analog Dial Temperature Controller. It is also called Blind Controller. This essentially means Open Loop, just control the fuel or energy input to the system to regulate heat. This is not a Blind Controller that way, it only cannot display the temperature value, that could be another reason it is called blind.

      Blind Dial Proportional Temperature Controller

      Dial cyclic timers were used to control heat, these were purely mechanical clockwork devices. They could regulate well, when the material flow (liquid) is constant and mains power is regulated. But when the job to be heated, varies in quantity, control temperature is close to ambient or when a precise control is required; closed loop controllers are used. Even a thermostat is like closed loop, as the bimetallic sensor is temperature dependent. But not good enough.

      This controller is closed loop, precision controller, only the digital display of temperature is absent. Fine one deg variations may not be easy in this.

      Blind Temperature Controller

      PCB Boards for Blind Controller -
      Discussions -

      Monday, February 12, 2018

      Electronics Tutorial for Robotics

      This tutorial will take you through the basic elements of circuit design, with the goal of preparing you to design and build robotic sensors and control systems. The experience of designing and building is at least as important as gaining conceptual understanding.

      Electronics Tutorial for Robotics

      An oscilloscope is an invaluable tool for learning circuit design -- it provides a way of seeing what is actually happening to your signals and waveforms. Unfortuantely, oscilloscopes are somewhat expensive. If you don't have access to a 'scope, it is possible to use the data-logging features of the Lego RCX in its place

      Electronics Tutorial for Robotics

      Using Chips

      Op-Amps are the first components we've used that are integrated circuits, which are also called IC's or chips. IC's are easy to use, but we need to know a few things about them.

      D. Sculley, Ph.D. an Alum of Tufts University wrote this tutorial in the summer of 2004, teaches  basics of electronics, created for Tufts Robotics.

      Tuesday, January 30, 2018

      Interface a PC to Measure or Control Temperature

      Thermocouple, RTD, Temperature monitoring is central to the majority of data acquisition systems, be it to save energy costs, increase safety, reduce testing time…whatever your reasons, you will need a device to measure the temperature - a temperature sensor.

      How to Use Your PC to Measure Temperature

      Thermocouples, resistance temperature devices (RTDs), thermistors and infrared thermometers are all types of temperature sensor. Which you choose depends on factors like your expected maximum and minimum temperatures, the accuracy you need and your environmental conditions.

      Interface a PC to Measure or Control Temperature

      Windmill data acquisition software with Microlink hardware

      752-RTD: RTD Resistance Temperature Measurement, Digital I/O, Counting, Analog Output
      • Measure temperature using RTDs or Pt100 sensors, and voltage signals
      • With extra hardware monitor thermocouples and strain gauge bridges
      • Includes the powerful yet easy-to-use Windmill software for Windows: no programming required
      • Connect up to 8 USB units to one PC
      Here is a way you can learn, How To Interface PC to the Outside World.

      Temperature Control with a PC

      delabs Notes

      This is a project that will help students learn both hardware and software aspects of a control system. Here you can test out an automation program on a PC with minimum external hardware.

      When you implement in the field, the system has to be a dedicated real time uC based product on custom firmware. Systems with OS + Software combination are not known to be reliable in Process Control. But OS + Software is good for Supervisory Systems which get their data from Real Time Controllers.

      So a front end controller must be Rugged, Non-PC based and Non-OS based embedded system. With a Robust and Compact (means fast) firmware.

      The firmware should be Polling or Interrupt based but with both internal and external watchdog. Most important a Power supply Management that resets system properly over Brown-outs and Black-outs. Even today some Embedded Systems i have to turn off and on after power resumes.

      Don't Forget, Multiple Watch Dogs and Multiple Power Management for graceful start of system !! Use one big SuperCap if you want. Else people will go back to Thermostats.

      Monday, January 29, 2018

      Thermocouple and Current Input Module

      This input module converts J, K Thermocouple and 4-20 mA Inputs to 0-2V Full Scale. These can be used for any voltage/current inputs too. The RTD module can be modified more easily for Voltage inputs. The control output can be On-Off or 4-20 mA/Proportional with another card. The 4-20mA I/O STC1000I is not complete in documentation.

      This is a Input Signal Conditioning Card for the Temperature controller. The voltage levels from sensors are either too low or need to be translated in level and span. Then for greater accuracy some linearization methods have to be used for a more precise reading. This also increases the cost. The circuits here do no cover the linearization see others in this and my related pages.

      Input Module - J and K Thermocouple with 4-20 mA

      Input Module - J and K Thermocouple with 4-20 mA

      The step or segment linearization can be done by transistor, diode or CMOS switches to accomplish varying attenuation/gain for stages of the curve or voltage levels. In Microcontroller systems it can be done by lookup tables or math.

      In some older digital systems without a MCU, the A to D drives the address of an Eprom Array to get a Digital Data for Display, as a linearized Reading. This Corrected Data was in turn made into analog using a D/A and then on to a Chart Recorder. This was a Logic only System of the early days. Microprocessor systems was expensive, power consuming and use to frighten people by getting lost in loops or a short nap.(they have fixed that, make sure you code properly).

      Wednesday, January 24, 2018

      PCB SSR Module - IO Module

      This is a PCB Mount SSR for Control of a Small AC load like a Lamp or a Contacter. It has Optical Isolation and has a Thyristor for output. This was in the I/O Module Standard.

      PCB SSR Module - Enclosure

      The MOC3041 A zero crossover optical triac driver is used here. The footprint is very small, many can be stacked in one small PCB.

      Read More - PCB AC Load SSR with DC control.

      You can see in the PCBs below  the distance between the input and output tracks is more than 5mm. The opto is itself a few kilovolts of isolation and we should take care of the creepage distance on the PCB and surface.

      This thing is Hermetically Sealed using a Alumina Powder filled Epoxy. This combination gives good thermal conductivity and Excellent Insulation.

      Contents

      Basic Electronics
      Basics of Electronics
      Product Production
      Work Discipline
      Testing Points
      Learning Electronics
      Electronics Theory

      Production Notes
      Prototype Fabrication
      Electrical Circuits
      Electromechanical


      Library
      Scots Guide Electronics
      Engineering - Wikibooks
      Design Lab - Jim Svoboda
      DC Circuits UOG
      Socratic Electronics
      Blobz Guide Electric Circuits


      Product Design
      Product Development
      Constant Current Source
      Good Voltage Regulators
      Insulation Resistance
      Digital Insulation Tester
      DN Schematic PCB 04
      DN Product Design 07


      Hobby Circuits
      VU Meter Circuits
      LED brightness control
      555 Incredible Chip
      Process Control
      liquid level measurement
      Thermocouples and RTD
      Design ADC Interface uC
      Thermocouple Amplifier
      IA Instrumentation 02
      Temperature on DMM
      Optical Proximity Switch
      Analog Mux - Data Acquisition


      Test Measurement
      Instrumentation Automation
      NI Test and Measurement
      DMM Digital Multi Meter
      Oscilloscope in T&M
      IA Automation 01
      Build Instruments
      Tektronix T&M Equipment
      Educators Corner – Agilent


      Power Electronics
      UPS Background
      Transformer Connections
      DN Power Electronics 03
      DN Power Electronics 02
      Half Bridge Convertor SG3525


      Embedded
      Interfacing Microcontrollers
      Embedded Process Control
      80C31 8052 Microcontroller
      Microprocessors and uC
      Embedded Systems Design

      Components
      Good Voltage Regulators
      Relays and Contactors
      Potentiometers Trimpots
      Prototype Boards Types
      Types of Capacitors
      Types of Switches
      Resistors How they Work
      Coils Transformers SMPS
      Mains Transformers Types
      DN Components Selection 05

      Tutor Gadgets
      Count-Up Timer
      Digital Logic Gates
      Electronics Tutors

      History
      Teaching Instruments
      Charles Proteus Steinmetz
      Muntzing a Circuit Design
      Teralab Electronics projects
      Historical Instruments


      Tables, Charts, Videos
      Binary and Hex
      Resistor Color Code
      Ohms Law
      Giga, Tera, Pico, Nano
      High Resistance Materials

      Analog
      School - Analog Design
      DN Analog Basics 06
      DN Op-Amps 01
      TI Semiconductors

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