Outdoor Services Crew

Sunday, January 15, 2012

What are those green boxes?

Those green boxes you see are actually part of our irrigation system.  They are called Toro VP Irrigation Controllers.  We currently have 68 of these controllers, each with roughly 32 irrigation stations controlling about 2,176 irrigation stations throughout the CU Campus.  They cover irrigation operation for the entire Main Campus, Williams Village, Research Park, and East Campus, along with some satellite locations including Newton Court and the CINC building.  We are continuously adding new controllers as the campus grows.  We will be picking up another 32 station controllers for the new landscape associated with the System Bio-Tech building at the Research Park.
These clocks are not like your normal irrigation clock in your home garage.  The VP controller is a very sophisticated controller.  It can be operated on its own just like your home controller but we control it with our Network 8000 computer through radio communication.  The original installation in 1991 used hardwire communication cable linking all the clocks back to the central computer.  Irrigation companies like Rain Bird and Toro had not started using radio frequency communication until a couple years later.  During those first years there were many challenges with that method of communication namely the amount of construction on campus would damage the communication wire.  As with any electrical system, the more splices you have in a wire the more resistance you have and eventually the system became unreliable with all the splices.  There used to be phone modem systems as well that communicated to the central computer but once the system started using radio control we eventually migrated the entire system to radio in the mid 90's and removed the modem systems.

A major challenge with using a radio system is location.  These controllers are placed in locations that are as inconspicuous as possible.  While that works great from a visual perspective it does not work well with radio signals.  Optimum radio signals are generally received as long as the two items communicating are in line of sight from each other.  That is why the majority of radio broadcasts are generated from elevated locations, such as Lookout Mountain, for most of our local radio stations.  The same reason you get great stereo reception the further away you are from the base of the Foothills and worse reception right along the Foothills is because you are more likely in line of sight of the broadcasting location.  Here on campus we have many buildings located very close together and on top of that some of them have extensive research equipment that generate plenty of interference for this type of system.

As the system continued to grow it became apparent that a more robust system was needed.  Previously the central computer spoke directly to the VP controllers, but as time went on and we started to use these systems in more distant locations we invested in a repeater system that was placed on the top of Folsom Stadium.  This location gave us the elevation we needed as well as the power to reach all the clock locations.  Now we are able to communicate with all of our controllers to include a controller at the South Campus tennis courts.  Since that system has been put in place we have been able to greatly expand the usage of these controllers.

We still have locations that have challenges that we are not sure of and have had pour reception at certain places.  In the first picture you see the two controllers but you also see a metal plate with a white stick in the middle.  We worked with our vendor to create the specific antenna setup to help us in some of our toughest locations.  We have many of these setups in use because even with the repeater on the stadium, we have some locations that are just extremely difficult.

In this picture you see the interface board that we can use to make changes to the system while out in the field.  This can include manual operation of the stations and we can make other system changes to the clock through this interface.  We do not use this option very often in the field, we tend to make all changes in the central computer.  There are a few key pieces to making sure we maintain a healthy landscape and these clocks are easily one of the most important pieces of equipment we have.

With any system, redundancy is always the safest way to operate a crucial system.  In the case that one part fails, there are ways to continue operating and not have catastrophic failure of the entire system.  One of those benefits is that we can actually use the field interface to create programs and run the irrigation system without the need for the central computer in the case of a computer failure.  Also in the case that we have radio communication problems, the clocks will continue to operate on the last known command for up to 2 weeks without new input.

As the irrigation companies have grown they have continued to help Turfgrass Managers sleep at night! Which I can say is a great thing.  :-)