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Water Management Solutions

Frequently Asked Questions


There are various levels of lightning control throughout the control system. Lightning controls are; -The computer comms cable is isolated from the field network wires by an opto-isolator. -Each station driving triac is protected by a MOV lightning protection device -Each Station Decoder power supply is protected by a MOV lightning protection device -The Logic Controller has it's power supply protected by a MOV lightning protection device Note that lightning protection on any electrical system is only effective dependant upon the severity of the lightning strike. A direct or near direct strike on the irrigation network lines could cause severe damage. For this reason we are not able guarantee thew system against lightning damage. The Nursery Logic system has been run through many tropical electrical storms on our Alstonville site without any equipment failure.

There are many reasons to replace an existing system with Nursery Logic. There are numerous control benefits that will allow you the flexibility to run the nursery the way to best benefit the plant growth. The 2 wire system will allow you to modify or add to your system easily in the future.

If you are running the Nursery Logic program then try the online help file. Select Help from the top of screen menu bar of press F1. The Programming Guide is also available through this menu. We also have technical sheets on various topics that are in the Documentation directory of your Nursery Logic application. This web page is steadily growing and will continue to offer solutions and advice on irrigation control. If you can't find it here then give us a call; Teven Logic, Chris Cusack or Trevor Tighe, ph.(02) 6628 7169

Process alarms can be incorporated within irrigation programs or can be programs within themselves. Examples of process alarms are; Low water pressure while watering Tank filling timeout (too long to fill) Hothouse over temperature (>40 DegC) Frost warning Propagation mist sensor dry for too long Water tank low level Filter needs flushing (high back pressure) Process alarms can be used in a number of ways such as Show warning on screen To start a program To stop a program Sound a buzzer, bell or flashing light

Most standard watering systems have a main control box which switched power to individual valves on their dedicated wires. An encoder system is far smarter. It runs 2 wires power grid around the nursery which are always powered. The Station Decoders are small boxes to which the valves are connected. The Station Decoders receive power and on/off signals from the grid. Each valve is given a unique address number recognised by the Station Decoders and can be individually turned off or on when it's signal is called. The advantages of an encoder system are multifold. The most obvious is the huge reduction in wiring required. The ability to check some of the field wiring. When a valve is turned on, the Station Decoder responds to the controller that it has done the task. This will alarm if there is any malfunction in the field wiring out to the Station Decoder (beside the valve). System expansion - additional Station Decoders can be added off the power grid if more valves are required with minimal wiring. The system is far more modular to add or remove valves as required.

Information from switiches or sensors can be read into the controllers to be displayed, logged and to interface with program logic. Examples of inputs that can be read are rain gauges, water level switches, pressure switches, temperature probes, humidity probes, light levels, moisture sensors etc.

More stations can be added by installing another Station Decoder physically anywhere on the 2 wire network. Adding one Station Decoder will gain 4 more stations and one input. The new stations and input are assigned an address number and are then available to be included in programs or manual control.

No, this system is designed to regularly interface with a computer. It is not designed as a permanent stand alone system.

Teven Logic has been selling the Nursery Logic system since 2003. We also run a family nursery "Bamboo World" which has been operating for over 10 years. We are members of the NSW nursery association and active in northern NSW industry. We regularly attend the Brisbane Trade days and most northern NSW/Brisbane nursery events. In Teven logic our staff has over 40 years of professional engineering experience gained in industry, particularly in the process control, process automation and industrial electronics areas. The combination of the qualifies engineering background mixed with hands on nursery experience is our greatest asset. Our Nursery is always used as a large test site giving us the ability to refine our products in the working environment prior to sales.

Network systems have been around for some years but are by no means common. The main reason has been their high cost. Our Australian ingenuity has finally delivered an encoder system at a far more economic value.

Adding more Station Decoders increases the numbers of stations. The system is currently limited to a maximum of 100 stations and 26 inputs. The limitation of the maximum number of Station Decoders able to be run on the system is dependent upon the site wiring system and power supply size. A field wiring system with large voltage drops will reduce the number of available Station Decoders. Large voltage drops in your field wiring could limit the number of Station Decoders you can run and can cause network errors. Contact Teven Control for further information if you are looking for a larger system.

Electrical interference can sometimes be a problem on the irrigation network but only in a small number of cases. Some equipment such as specific models of variable speed pump drives will add a large volume of high frequency RF noise onto the mains power and interfere with the Nursery Logic signals. We have only had this on one installation and the problem was fixed with an engineering solution. There are also some power supplies that are not compatible with the system because of their signal dampening characteristics. The power supply that is supplied with the system has obviously been tested. These issues are better discussed directly with us if they are of concern.

The computer interface is used as a programming and operational status interface. After the programs are downloaded into the Logic Controller, they will continue to operate without the computer. Most people use an existing computer in their business as it does not have to be dedicated to the Nursery Logic system. The PC should be reasonably modern (say within 6 years old) and run the XP operating system.

The Nursery Logic has been designed to use the industry standard 24VAC solenoid valves.

Installing and wiring the Nursery Logic is no more complex than connecting a standard irrigation controllers. It does not require specialised skills or equipment.

Any existing computers that are accessible to the “hands on” nursery management can be used for the controller. The two 24VAC irrigation wires will have to be run from anywhere on the network to the immediate PC area.

Data logging only occurs live when the program is runnings on your PC. The controller will still run the watering programs without the PC running but any information logged will not be recorded. The logging record will show a date/time stamp for when logging was stopped and started.