Hi all -

I am trying to find wireless transmitters wich will send continuously an ON or OFF state to a receiver. This setup has up to 100 transmitters
and only one receiver. We need to record those states duration in a database in a PC. Then we would treat the data and generate a printout.

These transmitter need to carry over a distance of 1000 feet. Its in a plant and the PC and receiver section will be in a remote office.
This is not a high speed application. Scan time could be 30 seconds.

No control is involved. Only monitoring and data analysis.

Can you give me a direction on where to search for such a thing. I have surfed toward Intrusion alerts, Automotive equipments and many more but
have failed to find anything that would suit this industrial application.

Many thancks

Pierre

 

Pierre:

You may find what you need at http://www.inovonics.com/.

I've used their products for both monitoring and control (discrete) with great success. They use 900 MHz Spread Spectrum technology with uniquely coded transmitters and have several models of receivers. You can
program the mode of operation to suit most needs.

Carl Ramer, Engineer
Controls & Protective Systems Design
Space Gateway Support, Inc.
Kennedy Space Center, Florida

 

The key component of this project is price. What have you budgeted for pricing?

This would determine if an "industrial" solution feasible.

Thanks,

Pat Schmid

 

Do search on net for ADCON Telemetry or SDI Radio Link. The SDI Radio Link is 4-20 ma by spread spectrum but they probably offer discrete signals.
Robert Phillips
City of Wichita Falls

 

Pierre,
There are several brands of RTU (Remote Telemtry Unit) to gather several inputs and send via UHF to the receiver. The RTU is solar powered and has a battery to keep the unit running over the night. You might want to try the brand "Baker" among the other Fisher & Rosemount. To improve the data management, some systems allows the data download as package when the receiver request for rather the single data transfer multiplexing method.
Jose Chong
Field Instrument Eng.

 

Pierre,
Speaking from my recent experience looking for an RF comm device, try using the phrase "radio telemetry," when you use a search engine on the Internet. (like excite) Most units are transceivers that run in the 902-928 MHz range and tend to be set up for transmitting data. There was one company out here in California called ScanData who has smaller units manufactured in Tx-Rx pairs. Be prepared to pay for it. I found nothing that would transmit single bits of info for less than $800 a unit.
If you find something less costly, please let me know...

Scott Jensen
Boeing, Long Beach
[email protected]

 

Pierre: You should also consider using narrow-band technologies. Depending upon how you structure your data and control the transmission, you can find transceivers for under $65.00 with open field ranges of up to 400 meters and data rates as high as 9600 baud.

Ed Meltzer

 

We evaluated the cost to be in the range of 1000 per transmitters and 1000 for the lone receiver. So for 5000 we could bring 4 signals to the PC end. Bear in mind that we do not look for anything other than one ON or OFF signal per x-mitters. This is not a full RF Network type of app. it's only a wire, pipes and manpower saving solution. I had a nice package submitted by the people of RFData in Florida. The question is how can we simplify to the extreme the installation, configuration and startup of this system without compromizing on riliability ...

During the dev. phase of our systems we sometime need temporarly to op signals from one place to another. This type of equipment I searh would
also give us this option ...

Pierre -

PS : This list is full of fantastic technicaly enclined people who help us make giant leaps in our technical education - Merci beaucoup ...

 

I have used many of rthe systems mfd in Autsralia by Elpro Technologies. They have 4-20ma, discrete digital and RS232 radio modems, that all operate on 460mHz. All data is CRC appended during transmission, and range is up to 10-12 Km without repeaters. the equipment is v easy to configure and works very well and is about US$700
Their address is : http://www.elpro.com.au/ourtable.html

neil

 

The RF Data Corp spread spectrum modules do not look to the user as a wireless LAN, but they do incorporate all the reliability features of a LAN,
including a radio protocol with forward error correction, on top of that a CRC16, and on top of that packet acknowledgements and retries at the radio protocol level. They look simple to install because they are a fully packaged turn-key solution with no firmware to develop, just hook up your connections to the terminal blocks (optically isolated open collector outputs and optoisolated TTL inputs) as if you had wires, attach the power connection (standard industrial power, from 9-38vdc, nominal 24vdc) and you're up and running. The transceivers take care of the rest and are a very reliable link , very insensitive to interference . I've tested them within 200ft of a large cellular tower , and they still established a good link through a number of metal reinforced walls in an industrial/office
environment. The approx $1000/unit allows a number of 4-8 simultaneous I/O connections per unit (discrete digital , or analog in or out) and units with more I/O (up to 64in and 64 out) are available, all in standard DIN rail enclosures .

 

Ed: Would you please advise me where I can find a $65.00 transceiver? Thanks. Ping

 

Pierre - can you please indicate what solution yous settled on?

 

Where do you get $65.00 transceivers?