Power line communications

[gtwy]

I was curious as to whether or not there was a relatively inexpensive way to convey a contact closure that could be transmitted via power lines to an autodialer a couple of miles away.
I have a municipal customer where one of their wellhouses has no autodialer to indicate when the pump motor/soft start etc has failed. There is another wellhouse in the near vicinity that has a cellular autodialer.
Most likely the power to each well is derived from poll mounted transformers and so the commonlity between stations is thru transformers.
It may be the best route would be to install another dialer at the site.

 

[VEBill]

A couple of miles is a long distance for the consumer grade power line Ethernet gadgets. I suspect that another (Pay As You Go?, hopefully $10/month) cellular autodialer is probably the best solution.

Municipalities often use those systems with the radios links, called SCADA? One can see the UHF Yagi antennas poking out of vaults all over the place.

 

[benta]

http://www.echelon.com/technology/power-line/

No affiliation.

Benta.

 

[gtwy]

Thanks for the replies- I've never had any dealings with power line communications- what got me thinking about it was it seems like Radio Shack something yrs ago (maybe they still do)that one could control receptacles remotely from within the house using modules plugged into the receptacles.
I'm interested now in kicking around on the web when I get time- seems like it would be suited more for the "LAN" setup, not not so much for leaving buildings, travel thru xformers etc.

 

[danw2]

There are wireless industrial cell phone modems that can take a dry contact input and reproduce it on the other end as a dry contact relay. The modems use a conventional SIM card. One pays for the service as though it were an SMS or text message.

The modems I've seen aren't 'cheap' ($1200 for a pair), but will work wherever there's cell phone service and 24Vdc power.

 

[mikekilroy]

what you are referring to is the x10.com system. Radio Shack sold them for years under their name. Some of us gluttons for punishment still use em. they use about 100khz digital sigs sent at zero cross of 120v line. they are typically ony about 5vpp and do NOT reliably go across transformers or typically even to the other phase of a typical homes secondary transformers 240v, atho there are boosters. I once was able to turn on and off lites in a house 1/2 mile away thru 2 pole tranformers - not reliably tho.

 

[gtwy]

Thanks for the posts- I'm sure the cell phone modem is what we'll end up with.
Seems like we used a x10 years ago at a small WWTP. It turned on a light at at another building closer to the main road where police could see if the pit was overflowing as passed by on off hours.