Archive for category Cellular

Industrial Wireless 101: Why do we need three frequency bands?

Regardless of what information you need to send, or where you need to send it, if your data is going “over the air”, you’ll need to choose a frequency in one of three ranges that do not compete with the FCC licensed bands for radio transmissions.

These three ISM (industrial, scientific, medical) bands are 900 MHz, 2.4 GHz, and 5 GHz. They’ve often been described as the industrial equivalent to Citizens’ Band radios, specified so they don’t interfere with broadcast radio signals.

History with technology would lead you to believe that the more Hertz you have, the better your radios will perform. But what you need to understand is that there’s a tradeoff. Each band has its strengths and weaknesses, and there’s a best use for each.

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How do I get an alarm from our station that’s 17 miles from here?

The situation: Plant operators needed notification and a log of events or alarms happening at a remote pump station, 17 miles away. 

The options:  First, the engineers considered installing dedicated leased phone lines with modems. But when one engineer asked if anybody really remembered or understood the AT codes the modems used (back in the early Internet days), and noone did, they dropped that option. Next, they investigated license-free wireless. That proved impractical: There were hills and valleys between the plant and remote station (no line of sight), and they’d have to lease property between the two locations and install repeater towers at an additional expense.

So, how did they get the data across 17 miles without leasing land or resurrecting obsolete technology? The answer was much simpler and less expensive than they anticipated. Read the rest of this entry »

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Which Industrial Wireless is Best for Me?

The answer to the Which Wireless is Best for Me? webinar question is, “it depends”.

With a decade of license-free industrial wireless experience under our belts, I’m confident that there’s a best wireless solution for everyone.  But which technology and network depends on what you’re trying to accomplish.  Some people just need a couple I/O points, others a plant-wide network to handle I/O and WiFi.

If you missed the webinar and want to see and hear the considerations for industrial wireless, go here: http://www.lesman.com/train/webinars/Webinar_Which-Wireless.htm

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Having fun with a cellular modem

A wired bench sample of the Phoenix Contact cellular modem kitI just got my hands on a cellular modem that can stream analog data from a remote site to a SCADA/HMI/PLC/DCS/PAC, send a text message or an email on alarm, or receive a text message that can control a relay output (yes, it’s all secure ! !).  

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