Radio Communications

[Bluenoser337]

It's been a number of years since I put together a radio (line-of-sight) SCADA system and I'm sure technology has made some great advances. I'm looking to install a system on a site about a mile square, with good line-of-sight possibilities for communications. There will be 6-8 remote "stations" and a central monitoring/control station, all within that square mile. Looking for opinions on brands to use, and any other experiences or ideas that may come to mind. Thanks!!

 

[VEBill]

I've seen some recent news reports about lack of security with SCADA systems. But I suppose any system can be hacked sooner or later.

http://www.theregister.co.uk/2007/11/30/canal_system_hack/

Jeff in NS.

 

[danw2]

Depends in part on what your data is.

Lots of vendors do serial or serial-to-ethernet (serial server) radio communications. B&B Electronics' catalog has a number of brands.

Phoenix Contact has I/O radio - analog-in to analog-out, discrete-in to discrete-out or analog/discrete in to Modbus serial out. I have had great success with its full 1 watt power for I/O wireless. All frequency hopping at 900Mhz.

Honeywell's XYR 5000 has one-way, battery powered transmitters that go to a central receiver which can do either analog/discrete out or Modbus serial out. Freq hopper at 900 Mhz.

I saw Honeywell'sust released XYR 6000 at the ISA show. It's a mesh network that requires a PC to administer a periodic security code updates through a wired gateway to all wireless nodes on the network - eihter mesh nodes or transmitter nodes. It's in a whole different category of security than the stuff I mentioned above. Very high security level. A node is rejected unless it is security approved beforehand.

The mesh nodes are comprised of 3 independent radio systems in one box:
- transmitter I/O network
- Wi-Fi band
- backbone for mesh network
The claim is that each network is optimized for its intended data and its intention is to deal with RFID, personnel locators, and other wireless technologies, in addition to I/O. It appears to be a well engineered, secure system for today's wireless and for expansion over time.

Dan

 

[Bluenoser337]

There are 8 stations all within a 1/2 mile radius.

There are only 16-24 max digital points and 2 or 3 analog inputs and outputs (all 4-20mA) at each station.

There will be a central monitoring station on-site, as well. The individual stations would continue to run independent of each other and the central station, in the event of total comm loss. It would be necessary to dial in to the central station and transfer program changes to any of the site controllers via the radio connection.

 

[danw2]

It sounds more like remote I/O than field devices from your description.

>necessary to dial in to the central station and transfer program changes to any of the site controllers via the radio connection.

That's a whole different ball game, and the wireless you choose will be dependent upon the physical layer and the protocol used for programming.

Is programming done via ethernet? TCP?

Is the I/O available through a standard protocol or a proprietary protocol?

 

[dpc]

Check Elpro. We've used their spread spectrum radios for several SCADA projects and have been pretty happy with them. There are others. What you are describing sounds achievable.

http://www.elprotech.com/