DanCo Systems, Inc.

 

ELPRO Technologies was founded in 1983 to provide a broad range of wireless products and systems for process and manufacturing applications. ELPRO sells its products in over 40 countries and on all seven continents.

ELPRO, based in Brisbane, Australia, is a world specialist in radio telemetry technology - sending data and information by radio. The company utilizes the very latest design techniques to manufacture high quality data radios and microprocessor controllers, combined with industry proven, dedicated software. We are able to provide a total design and manufacture capability to ensure all components integrate and complement one another for excellent reliability and performance.

This concept allows us to economically produce products and systems conforming to international standards. ELPRO's commitment to intensive and on-going research has contributed to its solid reputation as a market leader and innovator in the field of wireless I/O and radio modem products, and as a recognized supplier of wireless sub-assemblies for OEM customers.

ELPRO is owned by its four senior staff and the Queensland Development Fund, a private investment fund specializing in high technology companies.

What is Wireless Telemetry?

Wireless Telemetry is a method of transmitting information by radio. Signals such as switch statusd or analog signals may be transmitted to remote locations where the signals are re-created.

ELPRO wireless telemetry products provide secure and reliable solutions for a wide range of industries. ELPRO Wireless I/O and radio modem products are available in a variety of radio frequencies to cover different world regions, for both license-free and licensed applications.

ELPRO radio telemetry products fall into four telemetry categories.

What is "spread spectrum"?

Spread spectrum is a technique of transmitting on multiple radio channels. The technique was originally developed for the US Navy in WW2 - they were using radio-guided torpedoes but the enemy had learnt how to jam the radio channel. A research team (which included the actress Heddy Lamarr) developed a way for the radio transmissions to continually change frequency to avoid the enemy jamming.

• Direct sequence devices change frequency many times per data bit - effectively transmitting a radio message on many frequencies at the same time. The RF power is divided over the different channels. This technique can provide high bandwidth and thru put high data rates, with high reliability because of the "spread" transmission method. The disadvantage is that the effective RF power is reduced, reducing the radio range and penetrating capability.
• Frequency hopping devices transmit a data packet on one frequency and then change to a different frequency. The RF power is concentrated on one radio channel at any one time. The devices "hop" frequencies, and as each device hops to its own pre-set frequency pattern, the patterns of any two devices are different (or "pseudo-random"). This is how a large number of devices are able to share the same radio band. If two devices do hop onto the same channel and their transmissions "collide", they will then hop to different channels and re-transmit the message.

Because the frequency hopping technique concentrates the radio power on one channel at any one time, these devices perform better in industrial plants and factories where a strong penetrating radio signal is more important than high data rates.

There are two common ISM spread spectrum bands, at 900MHz and 2.4GHz. The 900MHz band has better radio propagation and penetrating properties than 2.4GHz, however the 2.4GHz band has wider channels allowing much higher data rates. Wireless LAN's are common in the 2.4GHz band where high data rates over short distance are required. For instrumentation and automation applications, where the amount of data transmitted is small however radio paths can be very congested, the 900MHz band gives better performance.

How far will the products transmit?

Reliable distance depends on the amount of radio power permitted by local regulations, and the degree of obstruction in the radio path. Maximum distances for license-free bands vary from more than 35km/20 miles to 1.5km / 1mile depending on the country's radio regulations. Using other radio units as intermediate repeaters extends this distance further. Licensed bands allow higher radio power to be transmitted, and can yield longer distances.

To reach the maximum possible distance, a line-of-sight path is required. The products will work over a path obstructed by buildings, trees or industrial plant, however the distance is reduced. A typical industrial application is less than one mile - the radio path can have a lot of obstructions and still operate reliably.