Wednesday, February 18, 2009
Capilano Computing - DesignWorks Schematic Capture
"DesignWorks Professional 5 doesn't just provide an environment for a single goal. It allows you to recapture your investment dollars by being flexible enough to handle all your design goals, be the goal a PCB design, Spice analysis, or simulation. You are not locked in to one PCB or simulation vendor."
What is LogicWorks 5
LogicWorks is an interactive circuit design tool intended for teaching and learning digital logic. No other software tool makes digital design easier, faster or more interactive than LogicWorks. The package gives you the power, speed and flexibility to create and test an unlimited number of circuit elements on-screen.
New in LogicWorks 5 for Windows is the ability to use a subset of the standard VHDL language to describe and simulate circuits. Hardware designs can freely mix devices and circuits described as schematic diagrams with blocks described textually using VHDL. See our VHDL page for a description of the language implementation in this version.
2631 Vikining Way, Suite 218 Richmond BC, Canada V6V 3B5
System Model, Types of Feedback Control, On-Off Control, Proportional+Derivative Control, Proportional+Integral+Derivative Control, Proportional+Integral Control, Third-Order Systems..
- Computer Interfaces for Instrumentation Systems
- Introduction to Sensors
- Troubleshooting Op-Amp Circuits
"Capacitive pressure sensors use a thin diaphragm, usually metal or metal-coated quartz, as one plate of a capacitor. The diaphragm is exposed to the process pressure on one side and to a reference pressure on the other. "
Tuesday, February 17, 2009
Tutorials for Electronics - Williamson Labs
- Engineering NOTEBOOK
- Elementary Electricity
- Intuitive Electronics
- Transmission Lines
- Mixers & Modulation
"He may be the Customer, and you the Engineer, but remember, you are both people. We as engineers often get a bad rap for not being "sensitive guys," not having people-skills."
Engineer under Construction
School Should Emulate Industry: - The Project Oriented Approach: Enables the Learn by Doing Paradigm.
Glen is like the Murphy for Electronics Engineering. There has be a "Laws of Glen" one can digest and precipitate from his valuable writings.
Friday, February 13, 2009
ESBCalc is a Freeware Scientific Calculator for Windows with Infix Notation, Brackets, Scientific Functions (Trigonometric, Hyperbolic, Logarithmic - including Base 10, Base 2 & Natural - plus more), Memory, Paper Trail, Result History List and more. v5 Includes support for Prefix functions so to evaluate log (10) you can enter log 10 rather than 10 log (which is the default behaviour)
ESBUnitConv is a Free User-friendly Windows Utility to easily convert between units of measurement. Includes Units for Temperature, Distance, Mass, Area, Volume, Pressure, Velocity, Acceleration, Force, Energy, Power, Fuel Consumption, Flow, Torque, Angles, Luminous Intensity, Illumination, Time & Radioactivity.
Online Calculator and Software Tools - On the Web
- The Electronics Calculator Website
- Electronics Calculators for audio circuits.
- Electronics Calculators - Daycounter
- Free online calculators about electronics
- Online Calculators - Laboratory of Changpuak
- Electrical Engineering programs HP 48
- Essential Online Calculation Resources
- Librarians' Internet Index Calculators
- Programmable Calculators - Viktor T. Toth
- Engineering Calculators & Converter Applets
- The Museum of HP Calculators
- Martindale's Calculators - Electrical Engineering
I use a Calculator from Casio
Thursday, February 12, 2009
These can be configured sequentially or to work synchronously, this depends on what customer wants. Both modes may give the same result. In sequential operation, Some of these counters-timers may need to wait for an external trigger or feedback from a limit switch or another process like pressure alarm. Then more Input options may have to be provided.
Basic Electronic Digital Circuits
Counters, timers, analog-process and its interconnectivity makes up the various process loops or chain-reactions in Machine control. The various types of sensors for measurement and feedback of analog and event parameters, monitor the mechanical system and communicate the data to the process instruments. The Actuators like Drives, Solenoids, Pumps, Valves and Heaters act in accordance to the commands of the control system. This regulates and manages the process or machine to deliver consistent and repeatable yield of the end product.
Wednesday, February 11, 2009
This is a Proportional Controller where the setpoint is derived from a Thumbwheel switch.
The conversion of Thumb-wheel Digital Data to Analog mV is similar to R-2R Weighted Resistor Network. In this case it is a 1-2-4-8 Binary Weighted Resistor Network. It has no Digital Components.
You can see an example circuit below for digit weights you just use like 10K-100K-1M etc. There is a problem of procuring 8M Resistors, so use series parallel combinations, avoid open presets. Trimpots can be used but then it raises the BOM cost.
1-2-4-8 Kilo Ohms may load opamp for high output levels. 1-2-4-8 Mega Ohms may be ok in the lowest digit. Greater than 10M designs are possible only in lab, not in commercial or industrial domains.
Make such R networks, solder array on thumbwheel, in some thumbwheels remove diodes or other connections. Club all of them, thumbwheels. One opamp will do. Use -2.5 V for positive mV output. The resistors should be close to 0.3% at least.
This Binary Resistor Network can also work with Digital CMOS Chips like CD4029. Use these chips on a separate supply, which is just a LM336 - 5V device. A digital thumb-wheel also can be used.
In this controller you can see a sensor open indication. When the sensor breaks, the temperature controller may continue to turn on the actuators or heaters, It may even Oscillate. So when a high impedance is detected in the sensor input terminals, the output relay is shut off and a LED is turned on to simplify operator's diagnosis.
Mount the controller a distance away from heaters, ac-drives and vibrating parts. Avoid direct sunlight on controller, fix controller in a sealed control panel. Earth the point where the thermocouple senses heat. Some heaters leak. The machine has to be earthed.
Proportional Process Controller Specifications
Front Panel Controls
Display - Process Value PV
This is a 3 1/2 digit display which shows the process value from 000 to 1999 as chosen by user it could be deg C, Kg/cm2 or Lts/hr.
Push Switch - Displays Setpoint
This is a push switch which when pressed, makes Display read SetPoint as required by user to control his process.
LED Indicates Relay ON or OFF in Relay and Pulse Output Units. Units with 0-10V or 4-20mA, Output LED is always OFF.
Vary SetPoint SP
This is an endless 10 Turn Potentiometer this is used to adjust SetPoint (SP) in tandem with Push Switch. Turning Clockwise it Increments SP till max. value, then turn anticlockwise to bring SP to Zero. Use a Plastic Screwdriver or Trimmer.(Tester).
Press Push Switch to make Display read SetPoint (SP), this is the user defined point at which process is controlled. Now holding Push Switch pressed, adjust SP Pot to change Set Point to required value, use a small screwdriver.
Back Panel Terminations
INPUT : 4 to 20 mA, Fused, Polarity is Important. From Sensor, DC Current.
OUTPUT : 4 to 20 mA, Polarity is Important. To Output Device or Actuator, which by using DC Current, drives 0% 4mA, 50% 12mA and 100% 20mA in Linear fashion.
SUPPLY : 230V 50Hz - L, N, E. Connect Proper Earth.
BAND : This is a Single Turn Potentiometer (300 deg) it sets the
Proportional Band of Control. Wide and Narrow are the ends of pot.
RESET : This is a Ten Turn Potentiometer (endless) it sets the
Integral or Reset or Error Cal. Inc. PV and Dec. PV are the two ends of pot.
Electrical Precautions -
- Wrong Connections are the cause of most equipment failure.
- Use Servo stabilizer for extra protection.
- Use a Very good earth connection.
- Use Fuses where appropriate.
- Crimp and Solder all Lugs.
- 4 to 20mA, 4mA 0% & 20mA 100%. < 4mA OFF, > 20mA ON.
- 4-20mA Maximum Voltage @12V DC ie Shunt 10 Ohms to 500 Ohms.
- Protection - use external fuse of 0.1A to safeguard from high energy circuits.
4 to 20mA, 4mA Displays 0% of Process Value '000' & 20mA Displays 100% of Process Value. This is to be specified by user as ... an example 750 Lts/hr.
Input @ 20 Ohms Shunt in STC1000PFC. Protection - Internal fuse of 2A and Semiconductor Protection Circuits to
safeguard from high energy circuits.
Environmental Limitations :
- Delicate Precision Instrument
- Maximum 50 Deg C, 70% RH Non-Condensing
- Acid-Alkali-Salt Free area.
- Equipment may fail if environment is Hot / Corrosive / Vibrating.
Cleaning and Maintenance : No Maintenance required, Clean front panel with moist sponge & Mild Detergent.
Power Supply : 230V AC 50Hz +/- 10%, Sine wave UPS & DG Sets.
Proportional Temperature Controller
A Temperature controller made with above process controller has the following changes in specs.
LED Indicates SSR ON or OFF. Pulse Output goes High Max 15V or Low 0V. High Pulse turns on SSR. and this is Indicated by LED turning ON.
Display - Process Value PV
This is a 3 1/2 digit display which shows the Temperature value in Deg. Centigrade
INPUT : Thermocouple, Polarity is Important.
OUTPUT : DC Pulse Polarity is Important. To SSR. Pulse Maximum Voltage 12V DC at a Load of 250 Ohms.
Read More here - Analog Process Control Circuits