1. Student working on schematic for his term project The use of hydraulics on agricultural machinery has increased dramatically over the last several decades. In order for a technician to be a successful diagnostician and problem solver on modern machinery, s/he needs to be able to read International Standards Organization (ISO) hydraulic schematic symbols. Troubleshooting in the past was possible by simply looking at the piece of equipment, looking at realistic drawings of hydraulic components or reading text in a service manual. Unfortunately, it is not possible to show the large number of complex interrelated hydraulic components and systems on modern equipment with drawings that depict the actual components. Additionally, it is quite difficult to show the inner-workings of components with drawings. ISO schematic symbols allow the technician to visualize how hydraulic components work individually and how they work within a system. The teaching of ISO hydraulic schematics is a daunting task if the student is initially given a schematic for a complex piece of machinery and expected to form an understanding of the hydraulic system(s). An effective approach to have students learn the language of ISO hydraulic symbols is through having the students draw their own schematics. If the student is given a series of increasingly complex systems to draw, the student constructs an understanding of the symbols and then reading complex schematics becomes rather simple. Once the student understands how the symbols are constructed, it is possible to diagnose any difficulty that occurs on a hydraulic system on a piece of agricultural machinery. Positive results of the technique with our students are apparent as they are continually complemented for their troubleshooting abilities through the use of ISO hydraulic schematics on internships at equipment dealers. Drawing ISO Schematics as an Effective Strategy for Students to Learn How to Become Proficient Diagnosticians

3. When hydraulic systems started to appear on agricultural equipment, manufacturers published service manuals with pictorials showing how each system operated. Pictorials do not work well with modern machinery because: There too many hydraulic components on current agricultural machinery to be drawn in this style Each pictorial needs to be duplicated several times to show how the components work in all working conditions and positions The required text to describe how the system operated needed to be translated for technicians around the world The ISO schematic to the right represents a hydrostatic drive system similar to the text and pictorial above. A technician can use the drawing to the left and fully understand how the system works. The manufacturer’s explanation of how a hydraulic system functions can be done is a variety of ways: Pictorial (above left) Text (above right) ISO Schematic (bellow)

4. All students in Basic Hydraulics class are required to draw an ISO schematic for the Lego pneumatic backhoe shown above. The project works very well in having the students think about how individual components work together as a system. Drawing ISO Schematics as an Effective Strategy for Students to Learn How to Become Proficient Diagnosticians The schematic below is for the school-owned Challenger M535B agriculture tractor. After drawing schematics with ever increasing difficulty, they are able to use the schematic for troubleshooting exercises in their laboratories. (Only 1/3 of the tractor’s hydraulics are displayed here)

5. Student inspects hydraulic bale tensioning system, bringing schematic reading skills to the field Example of a student drawn backhoe schematic Students working together on their term project. The assignment is to draw a complete ISO schematic for an actual piece of machinery.