Wednesday, January 30, 2008

Sequential Timer - Pressure Switch

This was built in a 96 X 96 Cabinet. It takes the process thru three timer delays and the pressure is measured after a certain stage and at a setpoint the process, job or DUT passes or Fails. It could be stress, strain or load testing on object.

Sequential Timer

User Manual - Sequential Timer - Pressure Switch

Related Resources
Simple Sequential Circuit -State Machine - This lab will implement a stopwatch mainly based on a finite state machine (FSM). Other parts contain display, timer, counter, etc...

Synchronous switching of multiple electrical devices - An electronic timer consisting of CMOS integrated circuits is described that synchronously switches multiple electrical devices on and off..

Tuesday, January 29, 2008

SSR and Transmitter Enclosure

This is the enclosure for the Encapsulated Mini RTD PT100 Transmitter and also Solid State Relays - SSR.SSR Enclosure

Potted, Encapsulated in epoxy, hermetically sealed. It has a Nickel Plated Aluminum Plate insert molded. For removing heat from BTA41600.

The plastic is a fire retardant high temperature grade. The epoxy is ciba araldite, fine alumina is filler. A transparent terminal cover for safety. It costed me an equivalent of 600-700 USD for tooling plastic parts.

See also ...

Three Phase Solid State Relay

Monday, January 21, 2008

Interfacing Microcontrollers

At Beyond Logic and Embedded Processor Control you will find interesting information on interfacing.

Real World variables are analog values, like the temperature of the Human Body. There may be Yes-No or digital events too, like the Water Level of a Tank or Door Close-Open. The former is measured by a Thermocouple and the Latter with a Proximity Switch.

These values from the sensors have to be Quickly converted to a digital form and fed to the the uC by an interrupt or cyclic polling of ports. The "How Quickly" determines How "Real Time" you system response is.

An analog value in instrumentation has to be at least 12 bit wide resolution, which is like 3-1/2, and the
The ICL7135 4-1/2 gives +/- 20,000 counts at full scale, nearly 14bit wide data. This can be interfaced both in serial and parallel data links. The serial method is used when optical isolation is required from the sensor to control circuits. If the sensor is measuring the temperature of a Transformer, an optical isolation is absolutely required.


delabs Technologies 06:48 20-Apr-07

Embedded Process Control

Microcontrollers are versatile for process control instrumentation, The Instruments need to be small and power efficient, they have to be immune to electrically noisy environments.

When such a instrument is mounted closed to big machines, it has to be resistant to vibration failure due to harmonics. When it is used in ships or chemical industries, they need to be corrosion resistant. This makes Industrial Instruments a challenge to design, as the reliability is next only to Medical and Military instrumentation.

In applications like data loggers, scanners and PID Controllers Microcontrollers are inevitable. The analog and digital counterparts that were built years back were difficult to maintain and very big in size. With a uC a 48*48 1/16 - DIN PID Box is possible, as shown here Newport Autotune PID.

Modular Automation like PLC uses many uCs. There are Multiplexers, Analog and digital modules controlled by uC. Modern Computer based SCADA have wireless interfaces and transmitters using uC based intelligent circuits.

delabs Technologies 06:48 20-Apr-07

Friday, January 18, 2008

80C31 and 8052 Microcontroller

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.

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.

delabs Technologies 06:48 20-Apr-07

Microprocessors and Microcontrollers

Analog devices like transistors and diodes lead to opamps and analog computing. This takes more parts but with fast devices can be real time. Then came Logic and Digital Circuits, here also big systems will take too many parts. A very Old hp Logic Analyzer instrument, could be HP1600A, had more than five large PCBs, Toggle Switches and numerous 74Fxx TTL Chips. I tried to revive it, it could not be fully restored.

Then came the solution the Microprocessor.  Here the entire system goes into the firmware and a Hardware. Tool Set in the Microprocessor made up of Logic and Math, sequentially used to perform the same operation that would require innumerable Gates in a plain hardware digital circuit. But as it performs the operations one after another, it takes time, hence the speed is defined by the CPU Clock Speed and Bus width.

When the External RAM and EPROM and other peripheral devices moved into the main package, MicroController were born. When more external devices merged with the MicroController. It formed a nearly complete computer, this is known as the SOC.
delabs 06:48 20-Apr-07

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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