Hanna Instruments HI 8050 - Manual (Page 4)

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THEORY OF FUNCTION THEORY OF FUNCTION THEORY OF FUNCTION THEORY OF FUNCTION THEORY OF FUNCTION
Irrigation is one of the most important operation in agriculture. With proper
irrigation the quality and quantity of crops can be significantly enhanced.
Correct irrigation is not a simple process: the quantity of water must be suffi-
cient for crops, and if not, photosynthesis and overall growth is impeded.
However, if the amount of water is more than required, plant growth may
become excessive producing a taller, softer and/or damaged product. The
Fertigation Controller can control the quantity of irrigation water based on
time or volume. Different sectors can be irrigated at different times during a
day with different water quantities. In the Fertigation Controller each irrigation
program provides control of pH and of the amount of fertilizer released to the
fields. When necessary, a specific program performs a pH correction by the
introduction of an acid or base into the irrigation water. pH control is based
on sensor input and a specified set point, while fertilizer control is based on
sensor input and setpoint or based on volume measuring. When the Fertiga-
tion Controller commands the addition of 1 or multiple fertilizers to the irriga-
tion stream, digital counters continuously monitor the quantity of fertilizer re-
leased in the irrigation stream and the overall amount of fertilizer is main-
tained based on a target prescription. Fertilization can be also controlled
based on conductivity of stream. The Fertigation Controller can command the
addition of multiple (1 to 4) fertilizers to irrigation water. The amount of fertil-
izer is set by the user for and controlled by a specific program (based on a
prescription). If a pH or conductivity control problem arises, the program
generates an alarm to inform the user. All operations of both control pro-
cesses are stored in memory and if needed takes the proper action. The Ferti-
gation Controller performs all necessary operations in the monitoring and
control of irrigation and fertilization processes. These operations are con-
ducted continuously throughout the day, month and year. To use and manage
the system properly, all the necessary control values must be set (Setup mode).
During monitoring operations (Consulting mode) the user can obtain infor-
mation about how the system and irrigation process are functioning, in addi-
tion to the history of all operations for current and previous days. To view the
required information on the display or set a specific parameter, the appropri-
ate display panel has to be selected, as explained in this manual.