Fun with Licenced Band SCADA Radios

Radio telemetry is a lot of fun.  It is part science, part art and part cross your fingers and hope it works.  We try to minimize the later through the use of software studies and site tests.  Part of the science is picking the right frequency for a system.  When Sterling Engineering Solutions started selling industrial wireless solutions in the late 1990’s everything we did revolved around 900MHz frequency hopping spread spectrum. http://www.phoenixcontact.com/global/news/248_7996.htm  If the radios did not have enough reach, we put in repeaters.  It was pretty simple, especially for our industrial customers with small geographic footprints. Municipalities that cover a larger area were a bit more problematic.

Four years ago, we were approached by CalAmp Dataradio to sell their licensed band IP data and serial data radios. Becoming a CalAmp distributor was a great move for us because it opened our eyes to the wonderful world of licensed data radios.  All the radios we had sold up to that point were 1 Watt 900Mhz and now we had UHF capability and a 10 Watt VHF radio in our arsenal.   The CalAmp radios were a huge improvement in reach for those larger, spread out systems.  It was like growing up with a .22 rifle and later discovering the power and reach of a .50 caliber.   

There are many advantages to licensed band radios over 900MHz. 

1.      Since all the radios are always on the same frequency, there is no “Master” radio like 900MHz unlicensed. That single point of failure you have with the 900MHz FHSS can be quite a liability. 

2.      That coax feed line cable used between the radio and antenna eats power, but it eats much less power the lower the frequency. So not only does the frequency cover long distances better, it has more power available at the top of that big tank.

3.       Line of sight for longer distances is not the Holy Grail with VHF or UHF like it is with 900MHz. The lower frequencies bend better around land masses and can shoot through trees better.

4.       A licensed frequency is protected for the user by the FCC. Yours truly approves the use of the Federal Government for this purpose.

The only disadvantage is a small fee due every 10 years. The price of the fee is usually offset by lower installation costs since antennas don’t need to be mounted as high with licensed systems.

A word of warning for you existing licensed band telemetry radio users.  The FCC is tightening the bandwidth of telemetry licenses.  If you are operating at 25MHz bandwidth, you need a new license and maybe new radios good for 12.5MHz bandwidth by the END OF 2012.  http://transition.fcc.gov/pshs/public-safety-spectrum/narrowbanding.html

Please call us if you would like to learn more. 

Remote PLC Interface like you have never seen before

This new blog is our latest effort to bring you even more information about the products we offer, applications we’ve worked on or solutions we’ve engineered. We also want to provide you with a forum for asking questions or commenting on something that’s worked for you. We hope you will read and participate in the discussion. We also welcome suggestions on topics you’d like covered.

One of Sterling's specialities is M2M communication. We been selling industrial wireless and industrial Ethernet since it first came out. We don't care what PLC you use, we can help you communicate with it better. One of our niche specialties within the communications field is remote communications.

This first blog is about eWon, a new line for us that blows away anything I have ever seen before for remote PLC maintenance communications. It is so different from the typical routers that we have always used that I know it will be adopted by every OEM or Systems Integrator who takes the time to look at it. Here are some of my favorite features:

1) You don't have to know squat about VPN's to have a secure connection.

2) You don't have to program any of the remote equipment for use with a router. Normally you have to program a gateway address into any IP device using a router. Not so with eWon.

3) Refer to feature 2. Since you don't have to program field equipment to talk on the router, this is an ideal solution for retrofitting older sites. You don't have to send personnel to the field to install and program this!

4) You don't need any firewall assistance from your customer's IT people. eWon works with Ethernet ports commonly used for web interface, not the PLC protocol ports you normally use. So whether you use Modbus devices, Allen Bradley, Siemens or whoever, your customer does not need to know what ports those protocols communicate on. They need only give you an IP address on the network.

5) In your office you treat the remote PLC just like you are connected to it sitting on your desk. You don't have to remember remote router WAN addresses. Through simple and free software you get a tabular listing of all your field locations. You click on the router in the panel you want to talk to and away you go. Your computer is now on the same subnet as your remote PLC equipment. No need to tell your PLC software to talk to a WAN IP address.

eWon can also communicate directly with your PLC's. Their devices can poll data, log the data and send emails or text messages with alarms. This is gravy for most folks but it is tasty gravy.

All of this costs less than most industrial routers that require many more layers of complexity. Give us a call to learn more. 888-554-2021.