Posts Tagged ‘Telemetry’

A Brief Description of SCADA System Signals

Sunday, June 19th, 2011

It has been a while, I left this site without any updates. So, here I present a basic of a SCADA system signal. It’s basic and have to describe it a way earlier but, left out with an assumption every SCADA engineer should have known it. Anyway, as a general reading, this topic should be one of important information for public readers.

basic circuit of instrument signal tappingThe most common current signal standard in modern use is the 4 to 20 milliamp (4-20 mA) loop, with 4 milliamps representing 0 percent of measurement, 20 milliamps representing 100 percent, 12 milliamps representing 50 percent, and so on. The use of a 4 mA reading to indicate zero is known as “live zero.” This helps to distinguish a zero reading from a “dead signal” or non-functioning equipment. The range of readings possible for a properly functioning system then is only 16 mA (20 mA – 4 mA). This 16 mA range is known as the “live signal.” The actual reading being recorded in mA is called the “process variable.” The PV indicates a percentage of a particular measurement being monitored. The table below shows the relationship between various PVs and their corresponding percentages.

signal comparison tableA convenient feature of the 4-20 mA standard is the ease in converting these signals to 1-5 volt indicating instruments, as the table on the left shows. A simple 250-ohm precision resistor connected in series with the circuit will produce arange of readings from 1 volt of drop at 4 milliamps to 5 volts of drop at 20 milliamps. The current loop scale of 4-20 milliamps has not always been the standard for currentinstruments. In the past, 10-50 milliamp signals were used more frequently. That standard has since become obsolete. The main reason for the eventual supremacy of the 4-20 milliamp loop was safety. Lower circuit voltages and lower current levels (compared to 10-50 mA systems) mean less chance for electrical shock injuries and/or the generation of sparks capable of igniting flammable environments in certain industrial applications.

An Overview of  SCADA Signal Calculations

Definition of terms

Dead signal: A reading from a non-functioning system that can be mistaken for a measurement.
Live signal:
The range of possible process variables. In a 4 – 20 mA system, any signal below 4 mA or above 20 mA indicates malfunctioning equipment. The range of useable signals is between 4 & 20 mA. Therefore, the live signal = 16 mA.
Live zero:
A reading other than zero used to indicate zero so that a zero reading can be distinguished from a dead signal. In 4 – 20 mA systems, the live zero = 4 mA.
PV:
Process variable. The signal reading, in mA, that represents a percentage of a particular measurement.

One of the more common uses for SCADA systems is the monitoring of storage levels. Formulas for making these calculations include:

mA to feet conversion

So, given a SWH of 30 ft, and board reading of 14.67 mA, the water level would be calculated as follows:

water level calculation

Kindly, do enjoy to use or share this information. Have a nice day.

Reference: Water Opcert School

Save sensor data to Google Spreadsheets by Codebox

Saturday, December 25th, 2010

I found this is really a good way to gather data, since Google Spreadsheets is free and can be accessed from any places in the world as long as connected to the internet. Plus, you can share it with selected persons you want. It’s quite useful for scientific researchers to share and analyze their findings. Check this out (completed with the codes):

The “Hello Arduino” section in Chapter 11 of Getting Started with Processing shows how to read data into Processing from Arduino. In a nutshell, the Arduino code (example 11-6 in the book) reads data from a light sensor and writes it out to the serial port. The section then goes on to describe a number of increasingly sophisticated sketches that retrieve and visualize the sensor data using Processing’s Serial library.

This Codebox shows you how to save this sensor data to a Google Spreadsheet. The cool thing is that you can then use any of the goodies that Google provides (charts, gadgets, maps, etc) directly with your data. While the light sensor is pretty basic, you can use this basic setup to record data from more sophisticated sensors, such as a Parallax GPS receiver module into Google Spreadsheets, and then create a map of where you’ve been that you could post as a gadget.

The sketch relies on the Google API Client Library for Java, which is a set of code libraries for interacting with various Google’s services (not just Spreadsheets). In researching this article, I found Processing guru Jer Thorpe‘s article Open Science, H1N1, Processing, and the Google Spreadsheet API a great inspiration. While it’s based on an older version of the API (version 1.0, while the APIs are now up to version 3.0), it’s a great introduction to interacting with Google.

Courtesy Make

DIY Arduino water meter with iPad display

Saturday, November 6th, 2010

TEAGUE Give Water from TEAGUE on Vimeo.

It’s another arduino stuff to be working on here. All related references are included:

Some of the folks over at Teague Labs have been noodling around with measuring water consumption. They’ve built a graphing water meter using a YellowJacket Arduino board with built-in WiFi and coolant flow meter from a PC cooling system to see how they used water around the office. Water conservation is major concern in many areas around the world. Tools that allow us to observe and correct our behaviors help us towards a path to sustainability. Schematics and source code are available if you want to try it out for yourself.

courtesy: Adam

These Tiny Magnetometers Detect Fields Generated by Human Heart!

Sunday, October 24th, 2010

3o7tuekr.jpg

How can i imagine this tiny and ‘poor’ little thing can help a human life? hmm… I’m still thinking.

At the National Institute of Standards and Technology (NIST) scientists have been working on microfabricated atomic magnetometers capable of detecting faint magnetic fields. The devices, about 1cm3 in size, were taken to the Physikalisch Technische Bundesanstalt (PTB) in Berlin, Germany where supposedly resides the most magnetically isolated building in the world. Using the tiny magnetometers, investigators were able to detect the magnetic signature of human heartbeats, perhaps opening up the possibility for a new modality to complement ECG.

Courtesy of MedGadget.com

IBM research on network of earthquake detector and locator

Wednesday, September 22nd, 2010

Computer servers in data centers could do more than respond to requests from millions of internet users. IBM researchers have patented a technique using vibration sensors inside server hard drives to analyze information about earthquakes and predict tsunamis.

“Almost all hard drives have an accelerometer built into them, and all of that data is network-accessible,” says Bob Friedlander, master inventor at IBM. “If we can reach in, grab the data, clean it, network it and analyze it, we can provide very fine-grained pictures of what’s happening in an earthquake.”

The aim is to accurately predict the location and timing of catastrophic events and improve the natural-disaster warning system. Seismographs that are widely used currently do not provide fine-grained data about where emergency response is needed, say the researchers. IBM’s research is not the first time scientists have tried to use the sensors in computers to detect earthquakes.

Seismologists at the University of California at Riverside and Stanford University created the Quake Catcher Network in 2008. The idea was to use the accelerometers in laptops to detect movement. But wading through mounds of data from laptops to accurately point to information that might indicate seismic activity is not easy. For instance, how do you tell if the vibrations in a laptop accelerometer are the result of seismic activity and not a big-rig truck rolling by? That’s why IBM researchers Friedlander and James Kraemer decided to focus on using rack-mounted servers.

“When you are looking at data from a rack that’s bolted to the floor, it’s not the same as what you get from a laptop,” says Kraemer. “Laptops produce too much data and it’s liable to have a lot of noise.”Servers in data centers can help researchers get detailed information because they know the machine’s orientation, its environmental conditions are much better controlled, and the noise generated by the device tends to be predictable. (more…)

Brilliant SCADA System that failed

Sunday, September 19th, 2010

A friend of mine shared an article about software failures. it’s a good stuff to read, where we can avoid some mistakes that previously been made by software developers. there is a SCADA software there – some of the problems that I’ve been encountered too in my life. check this out:

http://images.nakedmaya.com/Troll-Link1-sm.jpgNet-Herald – a monitoring application for water supply companies. It was a complex client server application that would receive monitoring data from specialized hardware and store that data inside a SQL database. The client displays that data in different graphs, provides printable reports or sends alarm messages via SMS if a monitored value is not within its specified limits. I developed Net-Herald as a perfect fit for that specialized hardware that is provided by a local manufacturer. That way, so I hoped, I could profit from their sales leads and would find a smoother way into these water supply companies. The downside of course, was that my software would only work with their hardware. (more…)

Arad Metering Technologies Conserves Water via Battery-Operated Drones

Sunday, August 22nd, 2010

remote meter reader
Illustration by Chris Philpot

The word drone may sounds related to any contemporary sci-fi flicks, or images of attacks carried out remotely on hostile lands, or even your high-school biology teacher’s voice. We don’t expect a drone to help us save water, but that’s what Arad Metering Technologies intends to do. The Israeli company’s battery-operated drone is one of the novel tools it’s deploying to help consumers and companies conserve H2O — and to make money.

Such an idea would come out of Israel is no coincidence. The country is poor in water and rich in tech innovation, much of it born of constant military conflict. Israel pioneered the use of unmanned aerial vehicles after it lost many fighter jets in the 1973 war. But Arad’s drones don’t fight: They read data from the company’s patented water-meter system to detect leakage or, in irrigation systems, drought.

The World Bank estimates that water wastage costs utilities $14 billion a year worldwide; in developing countries, 200 million more people could be served by the water lost to leaks and theft. Arad CEO Dan Winter says this is largely a consequence of how the business works in places where water is cheap or untaxed: “You train people to abuse water because they pay very little.”

water-drone
Photos courtesy of Arad Technologies LTD

With this innovation, instead of meter reading – it can provide real time monitoring of water supply infrastructures. Its technology can find irregularities — a pipe failure, an unusually low flow rate, or a too-constant one that could indicate a leak — in a few hours, rather than every 60 days as with a typical meter reading.

Arad’s system is built around what looks like a standard meter. The difference is on the inside, where you’ll find 3G wireless technology, a microcontroller, and 20-year batteries. Every 11 to 30 seconds, the system transmits data, which can be picked up by a drone (best for quickly covering big distances in remote areas) or by a drive-by or fixed-base reader. The data are then analyzed by computer to gauge how much water has been consumed, how much was lost, and even where tampering may have taken place. As a result, companies can save both water and man hours.

The possibilities for Arad’s services go far beyond water should be covering abilities to monitor everything from municipal infrastructure, such as traffic lights, to security-camera networks — basically any complex system prone to localized failures and waste. Arad has its own way, to proof drones could be associated with saving, not destroying; life, not death.

Courtersy: Tree Hugger, Fast Company

Distributed earthquake monitoring using laptop accelerometers

Thursday, May 6th, 2010

laptopNPRquakecatcher

This is a kind of brilliant idea, since current trends of laptops manufactured with accelerometer sensors. And this would be a large peer-to-peer earthquake warning system. Sounds like SETI@home, but for collecting data instead of processing it. From NPR.org:

Newer models of laptops manufactured by companies like Apple and Lenovo contain accelerometers — motion sensors meant to detect whether the computer has been dropped. If the computer falls, the hard drive will automatically switch off to protect the user’s data.

“As soon as I knew there were these low-cost sensors inside these accelerometers, I thought it would be perfect to use them to network together and actually record earthquakes,” says geoscientist Elizabeth Cochran of the University of California, Riverside.

So a few years ago, Cochran got in touch with Jesse Lawrence, a colleague at Stanford. They whipped up a program called the Quake-Catcher Network. It’s a free download that runs silently in the background, collecting data from the computer’s accelerometer and waiting to detect an earthquake.

Laptop accelerometers aren’t as sensitive as professional-grade seismometers, so they can only pick up tremors of about magnitude 4.0 and above. But when a laptop does sense a tremor, it’ll ping the researchers’ server. “And when our server receives a bunch of those, we then say, ‘This is a likely earthquake,’ ” Lawrence says.

No accelerometer sensor but still want to participate? That won’t be any problem since you can purchase a USB sensor for use on your desktop computers. A lot of these, reportedly, are being installed in public schools.

Courtesy: Make

Flood Triggered Automated Camera System (FTACS)

Tuesday, April 6th, 2010

flood-triggered-automated-camera-system_4.jpg

When the Department of Natural Resources of Australia decided that they needed to capture data about the natural flooding of a cave, they turned to a hacker to get results. The goal was to photograph the area during these floods with an automated system. In the end, they used a gutted Lumix digital camera mounted in a trash can, covered in aluminium foil. Though it sounds a bit silly, the final product turned out quite nice. You can see the build log, schematics, and results on the project page.

In this case the event they are trying to capture pictures of a cave flood with a Flood Triggered Automated Camera System. The system consists of a camera that is connected to a moisture sensor so that the a camera can start taking pictures when the sensor gets wet. Pictures will continue to be taken every 15 minutes until the moisture levels go back to normal. Since it is being installed in a remote location it needed to be self sustaining.

The water sensor is an interesting design since it has the ability of killing the power to the entire system when the conditions are dry. This is done by using a Darlington transistor feeding a relay.

Courtesy of Penguins Lab

Keep tabs on your car with Multidisplay

Wednesday, March 17th, 2010

161020092229.jpg

Stumble upon MultiDisplay car monitoring system. Unlike traditional systems that rely on interfacing with the OBD-II protocol and existing car computer, the MultiDisplay uses an Arduino and custom shield with a combination of sensors; including temperatures, pressures, throttle, Boost, and etc. The data collected can then be displayed on a 20×4 LCD or streamed to a PC with visualization and event recording. It’s an Arduino based open source display for interesting measurand´s of a car hosted on Google Code.

Courtesy: Multidisplay via Hackaday