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 Equip Utilite with Long Range Serial Data Link 
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Joined: Mon Jan 09, 2012 3:16 am
Posts: 351
Post Equip Utilite with Long Range Serial Data Link
Overview

Although Utilite features high data rate 802.11N WiFi and Bluetooth 3.0, the range of these technologies is limited to approximately 150 ft/50 m indoors and 300 ft/100 m outdoors - for a clear line of site. Longer range wireless data communication requires technologies other than Bluetooth and WiFi.

One method of extending the wireless data reach of Utilite is to use a 900 MHz, Frequency Hopping Spread Spectrum Radio System. For this purpose, I am using a pair of Digi International 9XCite Radio Modems. This system offers a specified range of 300 ft/100 m indoors and 1000 ft/300 m outdoors. However, with a clear line of site and using high gain, directional antennas, outdoor ranges of 2 mi/3.2 km are possible - under ideal conditions.

Unfortunately, the tradeoff for extending the range of the data link is lower data transmission speeds. For example, the maximum data rate for the Digi 9XCite system I am using is 38,400 baud. This slower data rate is fine for controlling and monitoring devices where small amounts of data are communicated periodically, but the system is not suitable for high traffic conditions such as internet access.

Harware Required

- Utilite
- Digi 9XCite USB Data Radio for connection to Utilite
- Digi 9XCite RS232/485 or USB Data Radio for connection to remote equipment
- Remote Equipment (sensors, monitors, controllers, etc.)

The System

Block Diagram
Attachment:
Utilite - 9XCite Data Link.jpg
Utilite - 9XCite Data Link.jpg [ 59.35 KiB | Viewed 2464 times ]


The 9XCite Radio Modem connected to Utilite via USB mainifests itself as a USB-serial device (ttyUSB0). No additional drivers were needed - they are included in Ubuntu 12.04 - Kernel 3.0.35 which I am using. The 9XCite is easily communicated with using a simple terminal program such as minicom and is configured using simple AT commands provided by the manufacturer.

The Digi 9XCite Data Link operates in the 902 - 928 MHz ISM Band, and features 25 channels. A measure of data security is provided through the use Frequency Hopping Spread Spectrum Techniques. Further, the Spread Spectrum capability offers a good level of resistance to narrowband interference.

Test Setup

The test setup used consists of a Utilite - 9XCite Master Station and a Windows Vista Laptop - 9XCite Remote Station. The Windows Vista Laptop is configured to repeatedly send serial data in order to simulate a remote monitoring station.

Attachment:
Test Data Link.jpeg
Test Data Link.jpeg [ 160.03 KiB | Viewed 2461 times ]



Results

As you can see in the video loop shown below, the link effectively transmits serial data - albeit not at super high speeds.

Attachment:
DataLink.gif
DataLink.gif [ 222.18 KiB | Viewed 2438 times ]



Conclusions

1. Radio data links such as the 9XCite System have the potential to enable Utilite to monitor and control a wide variety of remote devices over a considerable distance. This provides interesting possibilities for field operations.

2. Utilite again shows its ability to function is a wide variety of roles.


Sun Jun 01, 2014 3:42 am
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