Posted by Mike Fahrion on Wed, Apr 22, 2009 @ 08:44 AM
All over the planet, little Earthlings are working their Crayola's to draw pictures of our dynamic planet on recycled paper in celebration of Earth day.
(Regardless of your position on the state-of-the-planet, we can certainly agree that we're far better off than those that were celebrating Pluto Day).
There's no question that both individuals and companies everywhere are becoming increasingly aware and assertive about being "green." Sometimes it's driven by regulations like WEEE, RoHS and such. Sometimes it's driven by a marketing push, and sometimes it's driven by the realization that being green can actually have a positive impact on the bottom line.
What do I see at B&B?
Sure there's the regulatory front. We jumped quickly on the RoHS and WEEE wagon, but there are lots of little things as well. Aggressive "lights out" practices to save electricity. Recycling bins all over the place that not only make us feel good, but reduce dumpster expenses. Lots of little things that can add up!
What is your company doing? Things that make good sense that B&B should do too? Silly things in the name of "green" that make no sense at all?
Posted by Mike Fahrion on Fri, Apr 17, 2009 @ 09:48 AM
Communications is my thing. Eighteen years of building gadgets that allow all kinds of deviant devices to talk. It doesn't stop at just bits and bytes, I like to write too. Personality tests (don't ask) place me towards the extrovert side of the scale - so I like to communicate. Interestingly not many years ago that meant that I liked to talk, but lately I've found that what I really like to do is listen.
I've been pondering some startling communications trends a lot over the last few weeks. Follow me down the rabbit hole for a moment.
In the 80's, we wrote or typed our information. Licked a 20 cent stamp, addressed an envelope. Dropped it in the mailbox and waited one to two weeks for a prompt reply. Very quaint.
In the 90's, email blossomed beyond scientists and students to a viable method for not only business communications, but personal as well. Messages were delivered in seconds. And every so often we'd even get an email from an unknown sender offering to sell us something.
By 2000, cell phones were on their path to ubiquity. If you worked in sales or were a teen you had to have one. The stereotypical introverted engineer found them to be technical marvels with little practical use as frankly, more conversations with more people was not our idea of progress.
But by 2005 resistance was futile and even the most introverted Dilbert engineer had a cell phone...and had likely dropped the "land line," carefully packing away his old AT&T phone with his 8 track.
By 2007 a new paradigm evolved. While everyone on the planet had a cell phone, the only people that actually talked on them were born before 1985 (ouch...I know, that hurts). If you were born post 1985 you simply use your thumbs.
Folks, we're not just talking about rapid change, we're talking about a large and growing acceleration factor combined with a reduction in inertia. I wouldn't want to program a PID loop on this one.
Mr. Ethernet, Bob Metcalfe stated that the value of a network is proportionate to the square of the number of users in Metcalfe's Law. (If true, it's possible that 13 to 16 year olds are on the brink of world domination).
So where are we today?
- Email is for old people (the irony isn't lost on me here).
- Businesses are full of old people so email is still used. This will change.
- The last documented case of a teen being yelled at for tying up a "phone line" was nearly a decade ago.
- Next generation workers have been trained in a 21st century version of shorthand, able to accomplish all communications in 140 characters or less.
- Previous generations of engineers grew up without the web. The next generation of engineers grew up with instant access to hundreds or thousands of lifelines, all reachable within seconds, 140 bytes at a time. This will evolve into the most powerful network we've ever known.
What does this mean to you and me? What does it mean for our equipment, our systems? I've got a lot of thoughts on this, both philosophical and some practical.
The rate of change of human communications is dramatically outpacing automation systems. Products and systems need to pick up the pace. A tidal wave of increased expectations for communication systems is coming. Which edge of the wave are you on? Here at B&B we're paddling towards the crest, but it's moving fast and we're not there yet, much more pizza and Mountain Dew will be needed.
Sure you've seen lots of new stuff from the depths of the B&B engineering labs lately, stuff like Ethernet Serial Servers, Modbus Gateways, Wireless Modbus I/O, Build-to-order Industrial Ethernet switches, Gigabit and PoE Ethernet switches and even an industrial WiFi Access Point.
And bunches more. It's all good stuff with more to come. But start exercising your neurons now, because there is a next generation of products coming down the pipeline that will go beyond simply being a rugged and reliable data pipeline.
Talk back to me. What is it that you'd like to see out of your next generation communication systems? Getting data from point A to B is old school and will fall far short of expectations of up and coming engineers from the Net generation.
Posted by Mike Fahrion on Sun, Mar 22, 2009 @ 04:52 PM
Last week's eConnections newsletter may have been a bit light on technobabble, but it sure drew a lot of inspired responses. I've posted excerpts from my newsletter at the end of this article - but it's the dozens of great reponses that got me jazzed up, things like Divye from India who wrote:
Mike,
I am a doc in a far away land (read- Suburban Pathologist in India) and 'god honest truth' it is thrilling to read your newsletter. I am not an engineer or a qualified geek, but I agree with- 'create/improve processes' and that 'creativity will improve the world'.
You see most of our diagnostic works runs like an assembly line- Raw material-patient samples and finished product-Test results on a report.
In between there are analyzers, Information systems, skilled manpower, improved processed, I/O systems, and responsible clinical managers creating/ improving processes.
Or Jack from Oz who wrote:
Hi Mike,
Well since you asked ;-) I have taken the rest of the year off, cancelled advertising, unnecessary subscriptions, renegotiated insurances and a few other things and suddenly discovered I have saved thousands of dollars. Working out the overheads for a lost year of business for me means I would have less
losses than if I continued on, with the attendant costs etc.
Since our business is 100% Internet business, run from home.......its no problem. IF someone breaks my arm to supply something, yes I will do it.......but I am not looking for business right now.
You may think this extremely weird but the rest of this year will see me doing some research on new products, take a trip or two to some trade shows. Over the next 9 months or so, there will be a shake out, some manufacturers may close up, some of our potential customers will also (some have :-() Next year will see the stabilised market appear......it may not be much of a market, or it could be quite good.....who knows?
I will be equipped hopefully to deal with it, having been researching over the rest of this year.
I would suspect some of my competitors, who are simply box sellers and price cutters, will have gone too.....I have no sympathy for them. Many of them have lived high on the Hog, and have a high debt overhead in the process, I saved for the rainy day..... ;-)
This will see a more stable market for me to operate in, with reasonable profit potential in the future, next year.
So......make sure your bilge pumps work! Trim your sails for the oncoming storm and skillfully steer your boat into profitable waters, in the future! :-)
Inspired - both of them - and there were so many others - made my week! Here's the eConnections from last week (you can subscribe yourself over at www.bb-elec.com).
Dear Readers,
I don't know about where you live, but here in Illinois we just had one of those early-spring weekends that makes you smile, no matter the circumstances.
There's just nothing like a fresh spring breeze after a long, frosty winter to clear your head.
Forget the bailouts, forget your 401k has downsized to a 201k, and forget that our middle-aged sun is working on its 5 billionth birthday (in another 5 billion we'll have something serious to worry about).
Seem impossible? Try harder. There ain't a thing you can do on your own to solve those problems anyway.
Swear off CNN and spin up some Miles Davis instead. Quit reading USA Today and dust off a good book (Atlas Shrugged might be a timely read). Get off your treadmill and get outside and live a little.
Burying my head in the sand?
Nope - just a matter of focus.
In my little world there are perhaps a few hundred lives out there that I can directly impact. And some thousands more that I touch indirectly. That's where spend my energy. I'm not gonna save GM, not going to fix Wall Street and I'm not going to reform Lindsay Lohan, so I'm not going to spend my time worrying about them.
What have I been spending my time on?
- This month I've been tweaking B&B's product development process, a great effort between engineering, product management and operations. As customers, you will see the results.
- I've been working on our product quality processes (and if you've had a less than top notch quality experience with B&B I want to hear about it).
- I've started a new blog. http://blog.bb-elec.com/
- I wrote a new paper on wireless that I shared with you all last month and have been responding to your terrific feedback, such as:
- Paulo from Oz who wrote, "'10 Commandments of Wireless Communications' was well condensed, clearly explained and easy to understand. Well done Mike!!! It's a good help for those deploying wireless devices in old as well as new installations."
- Ted from a research vessel deep in the south Pacific penned, "Thou shalt continue to bring Mirth to my Draconian work shop of horrors. It sootheth my soul. Thanks, and Best Fishes"
I've posted the 10 Commandments wireless piece up on the blog. So if you missed it last month, and wireless is in your future, check it out.
What can you do in your world? Fix processes, or develop processes where none exist. Take on that instrumentation project. Add those next few I/O points to your SCADA system. Think of 10 things you can do to do more with less and make them all happen. There's never been a better opportunity to roll out your "A" game. Neither politicians nor bankers are going to revive the world's economy - it's you and I, and the ranks of creative geeks like us that are going to make that happen.
What projects are you driving in the face of slower spending? I'd like to hear about them.
Happy (Springtime) Connections!
Posted by Mike Fahrion on Wed, Feb 18, 2009 @ 04:50 PM
The specs say 20 miles, line-of-sight. Why can't I get the damn thing to work at less than 1 mile?
I wasn't alone in my frustration with making wireless work. Our tech support guys have worked with many of you that have grappled with wireless installation headaches.
I rolled up my sleeves and dug into it. What an education!
I distilled it down to The 10 commandments of wireless below. You can find this in our tech lib as well at http://bb-elec.com/tech_articles/WP33_10commandments_wireless_comm.asp
Have a read - follow these steps and you're nearly guaranteed a reliable and trouble-free wireless project! Let me know if you agree.
-Mike
10 Commandments of Wireless Communications
1. Thou shall know thy dBm and recall thy high school logarithms.
Radio Frequency (RF) power is measured in milli Watts (mW) or, more usefully, in a logarithmic scale of decibels (dB), or decibels referenced to 1 mW of power (dBm). Since RF power attenuates as a logarithmic function, the dBm scale is most useful. Here are some examples of how these scales relate:
| 1mW = 0dBm |
| 2mW = 3dBm |
| 4mW = 6dBm |
| 10mW = 10dBm |
| 100mW = 20dBm |
| 1W = 30dBm | |
|
| A 2-fold increase in power yields 3dB of signal. |
| A 10-fold increase in power yields 10dB of signal. |
| A 100-fold increase in power yields 20dB of signal. | |
2. Covet not high frequencies - as the lower the frequency, the more forgiveth the laws of physics and propagation.
Industrial applications typically operate in "license free" frequency bands, also referred to as ISM (Industrial, Scientific and Medical). The frequencies and power of these bands varies from country to country. The most common frequencies encountered are:
- 2.4 GHz - nearly worldwide
- 915 MHz band - North America, South America, some other countries
- 868 MHz band - Europe
As frequency rises, available bandwidth typically rises, but distance and ability to overcome obstacles is reduced. For any given distance, a 2.4 GHz installation will have roughly 8.5 dB of additional path loss when compared to 900 MHz. However, lower frequencies require larger antennas to achieve the same gain.
3. Honor thy receive sensitivity - as long-range performance is not a function of transmit power alone.
The more sensitive the radio, the lower the power signal it can successfully receive, stretching right down to the noise floor. There is so much variety in "specsmanship" for radio sensitivity, that it is difficult to make a meaningful comparison between products. The most meaningful specification is expressed at a particular bit error rate and will be given for an ideal environment shielded from external noise. Unless you're in a high RF noise environment (typically resulting from numerous similar frequency radio transmitters located nearby), the odds are good that the noise floor will be well below the receive sensitivity, so the manufacturer's rated receive sensitivity will be a key factor in your wireless system and range estimates.
You can often improve your receive sensitivity, and therefore your range, by reducing data rates over the air. Receive sensitivity is a function of the transmission baud rate so, as baud rate goes down, the receive sensitivity goes up. Many radios give the user the ability to reduce the baud rate to maximize range.
The receive sensitivity of a radio also improves at lower frequencies, providing another significant range advantage of 900 MHz (vs. 2.4 GHz) - as much as six to twelve dB!
4. Thou shalt be wary of radio noise and recognize situations whereth radio noise may hamper thine installation.
RF background noise comes from many sources, ranging from solar activity to high frequency digital products to all forms of other radio communications. That background noise establishes a noise floor which is the point where the desired signals are lost in the background ruckus. The noise floor will vary by frequency.
Typically the noise floor will be lower than the receive sensitivity of your radio, so it will not be a factor in your system design. If, however, you're in an environment where high degrees of RF noise may exist in your frequency band, then use the noise floor figures instead of radio receive sensitivity in your calculations. If you suspect this is the case, a simple site survey to determine the noise floor value can be a high payoff investment.
When in doubt, look about. Antennas are everywhere nowadays - on the sides of buildings, water towers, billboards, chimneys, even disguised as trees. Many sources of interference may not be obvious.
5. Thou shalt always know thine fade margin - lest ye have a wireless link that worketh not in rain, snow, or the presence of interference.
Fade margin is a term critical to wireless success. Fade margin describes how many dB a received signal may be reduced by without causing system performance to fall below an acceptable value. Walking away from a newly commissioned wireless installation without understanding how much fade margin exists is the number one
cause of wireless woes.
Establishing a fade margin of no less than 10dB in good weather conditions will provide a high degree of assurance that the system will continue to operate effectively in a variety of weather, solar, and RF interference conditions.
There are a number of creative ways to estimate fade margin of a system without investing in specialty gear. Pick one or more of the following and use it to ensure you've got a robust installation:
- Some radios have programmable output power. Reduce the power until performance degrades, then dial the power back up a minimum of 10dB. Remember again, doubling output power yields 3 dB, and an increase of 10dB requires a ten-fold increase in transmit power.
- Invest in a small 10dB attenuator (pick the correct one for your radio frequency!). If you lose communications when you install the attenuator installed in-line with one of your antennas, you don't have enough fade margin.
- Antenna cable is lossy, more so at higher frequencies. Specifications vary by type and manufacturer so check them yourself but, at 900MHz, a coil of RG58 in the range of 50 to 100 feet (15 to 30 m) will be 10dB. At 2.4GHz, a cable length of 20-40 feet (6 to 12 m) will yield 10dB. If your system still operates reliably with the test length of cable installed, you've got at least 10dB of fade margin.
6. Thou shalt use thine given powers of mathematics and logic when specifying wireless equipment.
Contrary to popular opinion, no black art is required to make a reasonable prediction of the range of a given radio signal. Several simple concepts must be understood first, and then we can apply some simple rules of thumb.
The equation for successful radio reception is:
TX power + TX antenna gain - Path loss - Cabling loss + RX antenna gain - 10dB fade margin > RX Radio sensitivity or (less commonly) RF noise floor
Note that most of the equation's parameters are easily gleaned from the manufacturer's data. That leaves only path loss and, in cases of heavy RF interference, RF noise floor as the two parameters that you must established for your particular installation.
In a perfect world, you will measure your path loss and your RF noise conditions. For the majority of us that don't, there are rules of thumb to follow to help ensure a reliable radio connection.
7. Thou shalt not allow leafy greens or mounds of earth between thine antennas; and thou shalt elevate thy antennas towards the heavens; and thou shalt never, ever, attempt a system at the manufacturer's maximum advertised distance.
In a clear path through the air, radio signals attenuate with the square of distance. Doubling range requires a four-fold increase in power, therefore:
- Halving the distance decreases path loss by 6dB.
- Doubling the distance increases path loss by 6dB.
When indoors, paths tend to be more complex, so use a more aggressive rule of thumb, as follows:
- Halving the distance decreases path loss by 9dB.
- Doubling the distance increases path loss by 9dB.
Radio manufacturers advertise "line of sight" range figures. Line of sight means that, from antenna A, you can see antenna B. Being able to see the building that antenna B is in does not count as line of sight. For every obstacle in the path, de-rate the "line of sight" figure specified for each obstacle in the path. The type of obstacle, the location of the obstacle, and the number of obstacles will all play a role in path loss.
Visualize the connection between antennas, picturing lines radiating in an elliptical path between the antennas in the shape of a football. Directly in the center of the two antennas the RF path is wide with many pathways. A single obstacle here will have minimal impact on path loss. As you approach each antenna, the meaningful RF field is concentrated on the antenna itself. Obstructions located close to the antennas cause dramatic path loss.
Be sure you know the distance between antennas. This is often underestimated. If it's a short-range application, pace it off. If it's a long-range application, establish the actual distance with a GPS or Google Maps.
The most effective way to reduce path loss is to elevate the antennas. At approximately 6 feet high (2 m), line of sight due to the Earth's curvature is about 3 miles (5 km), so anything taller than a well-manicured lawn becomes an obstacle.
Weather conditions also play a large role. Increased moisture in the air increases path loss. The higher the frequency, the higher the path loss.
Beware leafy greens. While a few saplings mid-path are tolerable, it's very difficult for RF to penetrate significant woodlands. If you're crossing a wooded area you must elevate your antennas over the treetops.
Industrial installations often include many reflective obstacles leading to numerous paths between the antennas. The received signal is the vector sum of each of these paths. Depending on the phase of each signal, they can be added or subtracted. In multiple path environments, simply moving the antenna slightly can significantly change the signal strength.
Some obstacles are mobile. More than one wireless application has been stymied by temporary obstacles such as a stack of containers, a parked truck or material handling equipment. Remember, metal is not your friend. An antenna will not transmit out from inside a metal box or through a storage tank.
Path Loss Rules of Thumb:
- To ensure basic fade margin in a perfect line of sight application, never exceed 50% of the manufacturer's rated line of sight distance. This in itself yields a theoretical 6dB fade margin - still short of the required 10dB.
- De-rate more aggressively if you have obstacles between the two antennas, but not near the antennas.
- De-rate to 10% of the manufacture's line of site ratings if you have multiple obstacles, obstacles located near the antennas, or the antennas are located indoors.
8. Antennas
Antennas increase the effective power by focusing the radiated energy in the desired direction. Using the correct antenna not only focuses power into the desired area but it also reduces the amount of power broadcast into areas where it is not needed.
Wireless applications have exploded in popularity with everyone seeking out the highest convenient point to mount their antenna. It's not uncommon to arrive at a job site to find other antennas sprouting from your installation point. Assuming these systems are spread spectrum and potentially in other ISM or licensed frequency bands, you still want to maximize the distance from the antennas as much as possible. Most antennas broadcast in a horizontal pattern, so vertical separation is more meaningful than horizontal separation. Try to separate antennas with like-polarization by a minimum of two wavelengths, which is about 26 inches (0.66 m) at 900 MHz, or 10 inches (0.25 m) at 2.4 GHz.
9. Cable loss
Those high frequencies you are piping to your antennas don't propagate particularly well through cable and connectors. Use high quality RF cable between the antenna connector and your antenna and ensure that all connectors are high quality and carefully installed. Factor in a 0.2 dB loss per coaxial connector in addition to the cable attenuation itself. Typical attenuation figures for two popular cable types are listed below.
| |
Loss per 10 feet (3 meters) of cable length |
| Frequency |
RG-58U |
LMR-400 |
| 900 MHz |
1.6 dB |
0.4 dB |
| 2.4 GHz |
2.8 dB |
0.7 dB |
While long cable runs to an antenna create signal loss, the benefit of elevating the antenna another 25 feet (7.6 m) can more than compensate for those lost dB.
10. Thou shalt recognize the issues of latency and packetization before thou issueth purchase orders.
Before you lift a finger towards the perfect wireless installation, think about the impact of wireless communications on your application. Acceptable bit error rates are many orders of magnitude higher than wired communications. Most radios quietly handle error detection and retries for you - at the expense of throughput and variable latencies.
Software must be well designed and communication protocols must be tolerant of variable latencies. Not every protocol can tolerate simply replacing wires with radios. Protocols sensitive to inter-byte delays may require special attention or specific protocol support from the radio. Do your homework up front to confirm that your software won't choke, that the intended radio is friendly towards your protocol, and that your application software can handle it as well.
Posted by Mike Fahrion on Mon, Feb 16, 2009 @ 09:33 AM
You know about my affinity for good ol' serial communications. Watching those familiar bits and bytes flow by gives me the same warm fuzzy feeling as sitting around a fireplace with stockings hung with care.
Elegantly simple and effective for so many applications.
But what story are those bits and bytes trying to tell, and how do they get the job done? More often than not, the protocol of choice is Modbus. Just like good ol' RS232 and RS485, Modbus is elegantly simple and singularly responsible for an amazing amount of automation around the world.
But, like the serial wires that carry its message, Modbus isn't always plug and play. Frustrating, real-world problems sometimes make Modbus a victim of its own simplicity.
Let's do a super-quick review of the three flavors of Modbus.
First off, there is Modbus ASCII. Communicating over 232 or 485, ASCII is ultra simple, human readable, 7 data bits, but not horribly efficient.
Then Modbus RTU. Also over 232 or 485, with 8 data bits and better error checking, RTU is much more bus-efficient than ASCII, but also more sensitive to timing.
And now we've got Modbus/TCP, which nicely wraps Modbus packets for use over Ethernet, delivering all the speed and networking benefits of TCP/IP.
Regardless of which Modbus flavor you choose, all Modbus messages are a master-slave configuration where the master (often a programmable logic controller, or PC running supervisory software), must poll each node to determine its status.
So dear reader, I'm pondering - would you like to hear more about Modbus? How it works? Solutions to problems like:
Or are your problems trickier yet? Things like:
- Connecting a Modbus ASCII device to Modbus RTU?
- Connecting two Modbus devices that are hardwired to different baud rates?
- Hanging Modbus serial devices on a Modbus/TCP network?
- Magically remapping hardcoded Modbus ID's to non-conflicting addresses?
If you're interested I'll share those solutions with you next month (or faster - just drop me an email). Don't hesitate to challenge me with other real-world Modbus problems that you've run into. I want to hear about them. I stand at the ready to take on your Modbus woes.
So between Christmas shopping and competing with the Smiths for the best Christmas display control algorithm on your block, drop me a note to let me know when Modbus has left you feeling Grinch-like and I'll do what I can to ease your protocol afflictions in the new year.
Posted by Mike Fahrion on Mon, Feb 16, 2009 @ 09:32 AM
We're now making our marks on a spanking new year. Like carving the morning's first run in fresh powder, or - for the indoor types - making your first mark in a new jar of salmonella-free peanut butter.
Exhilarating.
There sure is lots of change coming in '09. New economic prophesies, new President, new bailouts and apparently a new Ice Age here in the frozen Illinois plains. Lots of new, lots of change. As Churchill said, "There is nothing wrong with change, if it is in the right direction."
But what won't change in '09?
- The US still won't adopt the metric system
- Lindsay Lohan will still be the party girl that used to be an actress
- And Modbus will continue to bridge the technology gaps between the automation equipment of the twenty and twenty first century.
What made Modbus the de facto standard - the common denominator among hundreds of communications choices?
- It's thin and simple. It takes very little hardware and is easy to learn. Days, not months.
- It typically uses RS-232, RS-485 and Ethernet as a physical layer. Sweet.
- Modbus is designed to move raw data, regardless of function, making it flexible for vendors to implement in a wide variety of apps.
- It's free. No license, no royalties. Only barrier to entry is downloading the pdf specification.
Last month I intruded on your eggnog and shared a thimble-full of Modbus info. Today let's get past the smooth surface and talk about the top 5 Modbus problems - and how to solve them.
First, recall the three Modbus flavors.
- Modbus ASCII. Communicating over 232 or 485, ASCII is ultra simple, human readable, 7 data bits, but not horribly efficient.
- Modbus RTU. Also over 232 or 485, with 8 data bits and better error checking, RTU is much more bus-efficient than ASCII, but also more sensitive to timing.
- Modbus/TCP, which nicely wraps Modbus packets for use over Ethernet, delivering all the speed and networking benefits of TCP/IP.
Sounds slick from the 5000 foot view. So what turbulence lies under the surface?
Classical serial port problems. You've got 5 devices on your Modbus port hardcoded to 9600 baud and your boss just handed you a shiny new box that some newbie engineer decided to hardcode at 19,200 ‘cuz it's faster. Your face sinks like a kid on Christmas with a new cell phone without unlimited texting. What to do?
Or you've only got one available 485 port on your controller to talk to your five Modbus slave devices. But four of them are RTU and one is ASCII. Crud.
Your problems may lurk in murkier water. You've been tasked with adding some monitoring software to your four Modbus-controlled production lines but find that each of the four lines uses identical Modbus addresses. Ouch!
Here's an even better one. Your boss has asked you to connect another Modbus master to your Fig Newton line so he can monitor fig yield from his winter home in Boca. Everything works great until Mr. Pointy-Hair Technowiz finds the setting to crank up the polling rate to 10 milliseconds, crashing your Modbus controller and sending figs flying (hence the often misquoted adage, "when figs fly").
New Purchasing guy gets a wild hair and decides that he's switching to the "-E" option on the new controllers because surely the entire plant is Ethernet by now - leaving you with a truckload of installed Modbus RTU slaves and no 485 port. Yeesh.
So what are you, the lone voice of engineering reason, to do in face of multitudes of potential Modbus woes? Don't fret - I now have the answer.
From the clandestine engineering labs of B&B Electronics, secreted in the frigid tundra of Illinois, we've just released the solution to all of life's Modbus problems - the new Vlinx MESR series Modbus Gateway.
Bottom line, beneath all the marketing fluff, here's what the new Vlinx MESR series can do:
- Convert between ASCII, RTU and TCP - master or slave.
- Convert serial settings - baud rate, 232/485, stop bits - making any Modbus serial device play nice with its peers.
- Remap Modbus ID's on the fly - powerful stuff - you'll never have another address conflict
- Prioritize traffic from multi-master systems - prioritize by function code, Modbus ID or IP address to be sure the most important requests from the most important masters are handled first.
- Built-in Fiber Optic Ethernet options for long-distance, high immunity Modbus/TCP runs.
Check it out
Posted by Mike Fahrion on Thu, Nov 20, 2008 @ 03:09 PM
Before I get down to the serious subject of communication technology, I've gotta get something off my chest.
Ever had an engineering project that was so incredibly super cool you could pee your pants... it would increase efficiency, it would reduce defects, it would cut energy costs, reduce downtime, it would save you 17 trips from one end of the plant to the other each week, and it made absolute perfect sense to anyone who would actually LISTEN....
...but you could get no funding for it?
Dang frustrating, isn't it?
So here's my proposal:
Everybody else can get all the federal bailout funds they want, as long as Uncle Sam bails out yours and my virtuous, un-funded skunkworks projects.
We're not even asking for hundreds of billions of dollars. We're only asking for a few thousand bucks per person.
Deal?
Let's all journey to Washington DC together. We'll all pile on hundreds of Greyhound buses and call it the Million Engineer March.
Now then, onto the business at hand.
One of the most popular subjects of conversation these days is FIBER. I think fiber is real cool. You can run an arc welder, a CB radio and a Tesla coil right next to it and there's not a single dB of noise on the line. Not a single packet lost.
Plus, Serial-Over-Fiber is also growing in popularity. Who says the signal's gotta be Ethernet?
With our Fiber Optic Modems, any two pieces of RS-232 or RS-485 equipment can communicate full or half duplex over two fibers at a distance up to 2.5 miles (9 miles on single-mode!).
Industrial 232/422/485 to fiber converters
Want a port-powered version for your RS-232 application?
-Public utilities present demanding applications for Ethernet, especially Traffic Control. Temperatures are extreme, there are often high voltages nearby, and data requirements are increasingly sophisticated.
Ultra-rugged EIR series copper to fiber Ethernet converters meet NEMA TS1/TS2 requirements for traffic control equipment
-Remember the story of Bob Metcalfe drawing the concept of Ethernet on a napkin back in the 70's? Remember the battles between various protocols and networks, like Ethernet vs. Token Ring? The battles were finally won and now Ethernet is EVERYWHERE.
Sometimes I catch myself wondering things like... "I wonder how many TCP/IP packets are zinging around somewhere right this very second? How many were transmitted? How many received? How many packets were lost forever? And... what happens to lost packets anyway? Do they go to heaven?"
(I know, only uber-geeks like me ponder such questions.)
Once it's in TCP/IP it can go anywhere, and any Ethernet node is game. All you need is a flexible port. We have just such a product:
You configure it - we build it! Build an Ethernet switch or media converter to your specifications. Don't settle for a two box solution to get an unusual combination of copper and fiber. Simply configure the switch you need to perfectly fit your application and we'll build it.
Each fiber optic port is a "Flexible Port" that you can configure with the exact connection you need. Configure each flex-port to any combination of multi-mode, single-mode 15 km, 40 km, 80 km, ST or SC fiber or copper RJ45.
Now you can finally get that 8 port switch with two single-mode and one multi-mode port, or that 3 port switch that perfectly fits your system. We can manufacture one piece or any quantity. Your product is built and shipped within days, not weeks.
Test drive it for yourself
-When I go to the outdoors store, I can't help but pick up some piece of must-have camping gear to help scratch my wilderness itch (I get a similar itch at the hardware store, and the music store, and the motorcycle shop...hmmm). B&B has the equivalent of that for all Fans of Fiber Optic.
Each assembly is Optical Fiber Nonconductive Riser and can be used between floors through cable risers or elevator shafts. (Not for air plenums, though.)
OK, one last thing before I go.
The best products always start out as skunkworks projects. It's always a secret in the inventor's mind long before the committee approves it, right?
That, my friend, is actually the litmus test.
If some unsung engineer hero has been dreaming about it during his fishing trips and time in the restroom, it's sure to be a lot more coherent, better planned and executed, than something cooked up by a conference room full of people.
So... whether you get a Skunkworks Windfall from Uncle Sam this year or not, keep that dream alive. Your idea may be the next Ethernet-on-a-Napkin story.