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MAY 26, 2016 | WWW.PRODUCER.COM | THE WESTERN PRODUCER
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Telemetry; wireless data transfer key to precision ag PRECISION HAPPENS
TERRY A. BRASE
I
t seems that I have a greater appreciation for history as I age. What I’ve found is that many instances in history can be applied to these current times of advancing technology. Data communication is one of those technologies that have evolved as precision agriculture has advanced. As a favourite quote says, “there is always a better way of doing something; our job is to find it.” D at a c o m mu n i c at i o n i s a n important part of precision farming because this is what moves data instructions from the tractor oper-
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ator to the devices on the implement or yield data from the combine sensors to the operator. I like to compare data communications in precision ag to the development of electrical power. After Thomas Edison invented the light bulb, he had to invent a way to distribute the electricity so people could use his light bulb. He invented a method of generating electricity in the form of DC current, storing it in large banks of batteries and providing it to the public as a utility. Between his new electrical utility company and the light bulb, he was able to light up a section of New York City. The problem was that this was direct current at a low voltage, and the transmission of electric power to each residence required individual wiring. Soon the city’s landscape was overrun by electrical wires strung to every house. This concept parallels the early use of serial data transfer protocol in precision farm equipment. Serial is a unidirectional method
Wireless data transfer requires each device to share a wireless transmitter to pass information to the tractor cab or home office. | FILE PHOTO of moving data between devices: one wire going to every device and another wire back to the controller. As precision farming equipment increased and became more complicated, the bundle of serial cable would have been huge and hard to use on the implement. Edison had a smart assistant named Nikola Tesla, who had some pretty good ideas, including AC (alternating current) electricity. To me, creating a different form of electricity was a work of genius, but Edison did not like AC current, possibly because of the higher voltage, which led him to invent the electric chair to show the dangers of AC. However, AC could travel longer distances and be connected by one line to a string of houses. Tesla quit his job with Edison, formed his own company and won a contract
with the Niagara Falls hydroelectric generating plant to use his AC current. The United States was on its way to an AC based electrical grid, which we still use. Likewise, there is an alternative data communication protocol known as CAN-Bus. It allows bidirectional data communication through its wires with the use of nodes or modules. Modules are electronic boxes that serve as data traffic controllers and send data to devices, where they are needed, and avoid collisions between data transfers. CAN-Bus allowed manufacturers to use a couple of wires in a harness to communicate with a string of devices. The idea has caught on to the point that CAN-Bus is standard in most precision ag equipment. A third parallel in this story is that
Tesla was also playing with wireless electrical power transmission. You may have seen a Tesla coil demonstrated. This is a big silver ball on a cylinder that when turned on hums and throws harmless lightning “bolts” to a person’s hand as they reach out to touch the ball. Tesla had the idea to build a series of these large stations, which would then provide electricity to households without wires. This has not happened yet, but companies are researching the use of wireless electrical power to recharge small devices such as phones and hearing aids. The recent trend in precision agriculture is toward wireless data communication. This requires each device to share a wireless transmitter and receiver, which communicate with a transmitter and receiver in the tractor cab, or maybe in the home office. Telemetry is a term that has been used to describe this wireless transfer of data, and it has been useful, considering the amount of data that is regularly passed around between operators, devices on equipment, implements and the farm office. In the next few columns, I will explain how wireless data communication works and how it makes precision happen. Terry A. Brase is an educational consultant, former precision agriculture educator and author. BrASE LLC. Contact him at precision.happens@producer.com