If you want to control your irrigation valves, you will most likely need a water system in the Priva Compass. Basic, advanced and enterprise levels of water systems are available to you allow you to connect your water system in many different configurations. These configurations can be combined to allow you to customize your water system to fit your needs. These configurations include:
This article will explain how each of these configuration options are part of the Priva Compass water system.
Valve coordination allows you to make sure that all your irrigation valves do not turn on at the same time. There are two ways that you can do this. The first way is to set a maximum number of valves that can turn on at any given time in the water system. For instance if you set one valve to turn on at a time, the water system will make sure the valve has completed its cycle before it turns on another valve, if you set two valves to turn on, the water system will allow two valves to turn on at once. As soon as one of the valves has completed its cycle, the another valve can turn on as long as no more than two valves are on at a time.
A second option is to set the capacity of the water system. This capacity is defined by how much water your system can provide at any given time. Each irrigation valve has a capacity and the system will ensure that the valves will not ask for more than the water system can provide. For instance, if the valve capacities are set at 1 cubic meter per hour and water system has a capacity of 5 cubic meters per hour, the water system will allow up to five valves to run concurrently.
System pump control
The system pump provides the water for the irrigation valves. It runs whenever there is a demand for water.
The flow sensor monitors how much water is being sent to the valves. When a flow sensor is added to a water system, valves can be controlled based on the quantity of water delivered instead of being controlled for a specific amount of time. An alarm is triggered if the flow is too high or too low.
An external stop is an input to the Priva Compass that indicates that the water system must stop. The external stop is often tied to a water pressure switch or a water level float and indicates that there is not enough water to continue irrigation. When the external stop is engaged, the water system stops and the irrigation valves close. When the external stop is released, the water system will restart where it left off and the valves will reopen. The external stop can be set to stop a valve in mid cycle or it can be set to allow all the valves that are currently open to finish their cycle before shutting the pump off.
In the basic water system, you have a single generic external stop. In the advanced water system, you can have multiple external stops. The additional external stops are dedicated for a water system pump failure monitor and water supply monitor.
Electrical Conductivity (EC) is a measure of how well the irrigation water conducts electricity. It is used to monitor the amount of dissolved salts in a solution. EC is used as an indicator of the concentration of fertilizer in the irrigation water.
The Priva Compass can control the EC level by adding fertilizer to the irrigation water. You use dosing channels to inject various fertilizers into your water to maintain desired EC levels.
pH stands for potential hydrogen. It is used as a scale that is used to measure the acidity of water, based on the amount of hydrogen ion activity in the water. Having the proper pH level in the irrigation water is a key for healthy plants.
The Priva Compass can control the pH level by adding acid to the irrigation water to decrease the pH level or by adding alkali to the irrigation water to increase the pH levels. You use dosing channels to inject acid or alkali into your water to maintain desired pH levels.
The groups of settings that determine the desired EC and pH levels along with the selection of dosing channels used at one time is called a recipe. You can define a number of different recipes in the Priva Compass and select which recipe you wish to use for each crop. It is also possible to use independent recipes. These are used when you want the water system to start up and mix a recipe but do not want any irrigation valves to open. The water system can then provide irrigation water for hand watering or for systems where the irrigation valves are not controlled by Priva.
When recirculating water in the greenhouse, there is already an amount of fertilizer of in the water you are reusing. You can use dosing channels to mix the recycled water with the supply water to maintain supply water with a consistent EC level. This is separate than the regular EC control and uses a separate EC sensor. Growers that use EC precontrol will also use EC control to add necessary nutrients to bring the EC level to the desired level.
Filters are often used in water systems to remove deposits from the water before it reaches the plants. If the filter is a sand filter, it needs to be cleaned by performing a backwash on the filter. The backwash procedure consists of turning off the water system pump and running water backwards through the filter, forcing the collected deposits out of the filter. The Priva Compass can trigger the procedure based on different conditions and provides the controls for various valves and pumps that are needed to perform the backwash procedure.
A rinse valve can used in a water system when you are switching from one recipe to another recipe. Typically when switching recipes, the water that has already been mixed and is sitting in the irrigation line has the wrong recipe. The rinse valve can open for a period of time after the water system has started and before any irrigation valves open to rinse the incorrect water out of the irrigation lines and fill the lines with water of the correct recipe.
Custom control programs
The custom control programs are part of the water system and can be used to control pumps and other equipment as needed.
Irrigation tank control
The Priva Compass can also control irrigation water tanks. These tanks can be used if you wish to have different supply water based on the fertilizer recipe you make. They also can be used for day stock tanks to allow you to prepare the irrigation water for the greenhouse ahead of time. They can also be used for drain tanks where you collect the runoff water of the irrigation valves in order to reuse the water.