OT Help with measuring temperature in plant

Well, I would take the split oak that you have stored by your clothes dryer vent and place it around the 33 locations. Using binoculars from the front office, you can observe whether the splitting is continuing and the mold is growing.

Graphing the observed results (using a deseasonized negative-exponential chi-squared curve), you should be able to determine the air temperature from the chart you draw.

On the day of 21 Feb 2006 05:35:10 -0800... "stryped" typed these letters:

Sure. I used to work with industrial process control equipment. Most modern PLC's (Programmable Controllers) offer an ethernet option for connection to a computer network. You could mount temperature sensors (PT-100 RTD's Thermocouples... etc) at the 33 locations. The choice of temperature sensor would be determined by the degree of accuracy desired, temperature range, and the distance from the controller. The sensors would be wired to a compatable PLC set up to monitor the temperatures. With the ethernet option any computer on the network with compatable software installed would have access to these temperatures. Any place that does industrial automation should be able to help you with this project.

Hope this helps.

Omega Engineering, in NJ I believe, specializes in temp. stuff. 20 years ago they were measuring to .001 degree! They would for sure have a whole system for your app.

The were recently featured on a very inneresting crime ditty (mebbe an A&E/Bll Kurtis thing), where their IT guy almost bankrupted this multi-multi million dollar business by corrupting every data file for all their cnc equipment. Quite a story. Used a little DOS batch file, iirc.

Check out

Ditto! Call Honeywell or look for Instrumentation on the Google. Bugs

In real time ? Do you want to spend money on doing this (real money)?

One of the best ways I've seen this done was with Dallas iButtons (the temperature loggers) stuck to the walls and a simple handheld data logger. Walk round the plant once a day / week and collect a temperature / time chart logged at intervals from each logger. Best part is that it was dirt cheap to implement.

Don't get me wrong -

If you do it - or your people - look at this site :

Honeywell is a good company - and can do it if you shop it out.

Martin

Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder

stryped wrote:

There are plenty of expensive high-tech solutions that may be more than you need.

What accuracy do you require?

Do you just need to be able to check temp at the various remote locations from the office, or do you need automated computer datalogging?

Is there already a LAN in place that runs near all 33 remote points? Even if there is, would it be unthinkable to run twisted pair from each point back to the office?

There are digital devices that could all reside on a single twisted-pair daisychained to the various points, but in some cases it might be less expensive to just run wire to each point -- dirt simple low tech if the cost of running wire would be low enough. No codes apply so anybody could run the wire however is easy, like running doorbell wire or telephone or intercom wire.

This could be done for a few bux per point or a few hundred bux per point depending on your requirements. Example: there are silicon sensors as LM334 that sink current in proportion to temperature. They cost about $1.21 each in onesies from Digi-Key. Ancient tech -- but they work. There are others as well, e.g. AD590 from Analog Devices. Because they are temperature-sensing current sinks, they can operate over any length of twisted pair line from inches to miles. A local consulting engineer of your choosing could devise a central box to use these however you might want to do, anywhere from a

OK, you're a medium-large operation, and I expect you have some savvy electrical maintenance people. You can do this, without spending a lot of money, IF you have someone who can set this up along with their regular job, and who doesn't mind learning a few new things. BTW, they can maintain it later...

If your measurement points can be all on a cable that is less than about 200 meters long, you can probably do it on one CAT5 cable, using "1-Wire" temperature sensors that cost about $6 each (BEFORE you mount them on a board, or terminal strip, and put them in some enclosure on some wall)... Otherwise, you may need two cables. In fact, two separate cables, each with 1/2 the sensors, distrubuted properly, gives you some redundancy in case of a fault.

Look at:

I strongly suggest you use one of their 1-wire driver chips, for long cables!

They and other suppliers have Serial-port or USB to 1-wire LAN adapters you can buy.

Each thermometer has a unique address, so many can be connected on the same pair of wires. It's best to supply +5V to each sensor (Easily done with spare pairs in CAT5 cable. )

With more software work, these thermometers can each have a high and low temperature alarm value set, and software can poll for "Who's got the alarm?"

The whole thing depends on who is going to figure out and set up a system.

Regards, Terry King ...On The Mediterranean in Carthage

We did something like this for a large Chrysler plant (several hundred points). Cost for only 33 points would probably be around 250/point + installation with a network web browser based interface and stable platinum RTD sensors.

If you want much more cheaper (tm) up-front cost, a portable digital temperature meter and a clipboard is pretty hard to beat, but air temperatures take a while to settle. I wouldn't trust inexpensive consumer grade thermistor-based meters for much.

Best regards, Spehro Pefhany

Google the hell out of "Dallas one-wire" This is by far the easiest way to attach hardware to a computer (for very small values of computer). There are simple interfaces to serial, parallel and probably (by now) USB conenctors. The other advantage is that it's a simple bus interwiring with two-core bell-wire. All the one-wire devices have individually addressable IDs and they can all share the same physical wire. Works for both input and output.

The same people also make a $50 tiny single-board computer (TINI) that can link one-wire to a network and act as a web server. Very simple Java programming does the rest of the interfacing.