Controls for Precision Agriculture

I.

History

Description

 

May - July

1996

An irrigation control system was implemented on a ten span 1200' Center Pivot near Aberdeen Idaho on wheat crop with a control network using Echelon PLC technology. Valves along the pivot lateral were controlled in three zones per span. Each sprinkler drop had two valve/nozzle sets to control the flow in four stages of 0, 1/3, 2/3 or fully on. Papers reporting on this system can be found in the following references.

  1. R.W. Wall, et. al., "Center Pivot Irrigation System Control and Data Acquisition Communications Network for Real-time Variable Water Application", Proceedings of the 3rd International Conference on Precision Agriculture, June 23-26, 1996, Minneapolis MN, pp. 757-766.
  2. R.W. Wall, "Agriculture Irrigation System Control and Data Communications for Real-time Variable Water Application", 1997 Spring Echelon International User's Conference, San Jose, CA, May 19, 1997
  3. B.A. King and R.W. Wall, "Digital Power Line Carrier Control System for Optimum Operations of Variable Speed Pumping Plants with Center Pivots", 1997 ASAE Annual International Meeting, Aug. 10-14, 1997, Minneapolis, MN, paper No. 972191.
  4. B.A. King, R.W. Wall, et. al., "Field Scale Performance of a Variable Rate Sprinkler for Variable Water and Nutrient Application", 1997 ASAE Annual International Meeting, Aug. 10-14, 1997, Minneapolis, MN, paper No. 972216..
  5. R.W. Wall, “Sprinklers and Power Lines,” IEEE Computer Applications in Power, Vol. 14, No. 2, April 2001, pp. 25-29.
  6. B.A. King and R.W. Wall, “Secondary, Spatially Variable Chemical Application System for Site-Specific Crop Management Using Continuous-Move Irrigation Systems”, 2001 ASAE Annual International Meeting, July 30 – Aug. 1, Sacramento, CA, paper No. 01-2021.
  7. R.W. Wall and B.A. King, “Networked Protocols for Efficient Distributed Control in Agriculture”, 2002 ASAE Annual International Meeting, July 28-31, Chicago, IL, paper No. 02-3011.
  8. B.A. King, R.E. Reeder, R.W. Wall, and J.C. Stark, “Comparison of Site-Specific and Conventional Uniform Irrigation Management for Potatoes”, 2002 ASAE Annual International Meeting, July 28-31, Chicago, IL, paper No. 02-2175

Site Pictures:

 

Sept.

1996

An irrigation control system was implemented on a three-span linear-move agricultural irrigation system on the University of Idaho Aberdeen R&E station. The hardware for this system was identical to the system install in May 1997. However, instead of using step-wise control, a proportional system was implemented using a new valve design by Dr. Brad King. Proportional control was obtained by pulsing the new valve in a PWM fashion with a one-minute duty cycle. Papers that describe this system are soon to be published.

 

June-Aug,

1997

The third agricultrual irrigation system was implement on a three span center pivot irrigating a field of famous Idaho potatoes. This system used step-wise sprinkler control similar to the first system described above. CEBus networking technology was used instead of Echelon. Papers that report on this system are now in preparation. The following pictures show some of the equipment used at this site. The end-gun on this system accounts for almost 30% of the flow on the pivot when it is turned on. Control of the chemigation pump is necessary to maintain constant chemical concentration in the presence of such radical flow fluctuations. Dr. King, an agricultural engineer, is truly a man outstanding in his field but no one can say he has a big head. He is responsible for modifying the code from the first system described above for the master controller based on the V25 microprocessor. This unit provides the man-machine interface as well as the copmuter links for exchanging data log files, new operational watering maps, as well as revised control code. Inside, one can see the V25 master computer board as well as the 8051 node electronics using CEBus networking on the 480VAC power line. Unlike the first system, no speed control was employed on the water pump th maintain constant pressure. In August, Steve McGill, a a regional editor for John Deere's trade magazine, Furrows, came to visit the site. He will be writing an article on the Blackfoot system and it is scheduled for publication in the winter of 1997-98.

II

Current

Projects
  1.