Hanna Instruments HI 8050 - Manual (Page 9)

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alarm is triggered. For more information on the propotional band please
consult the proportional control section.
Given a conductivity alarm condition, conductivity control can be main-
tained if “Ctrl on EC alarm” is selected using panel number S54
S54 S54 S54 S54 (ALARM
BEHAVIOR).
Statistical values of total conductivity are displayed on panel C20
C20 C20 C20 C20 (TOTAL
AVERAGES). For the average conductivity of each irrigation program see
panel C21
C21 C21 C21 C21 (PROGRAM AVERAGES) and for average conductivity of each
individual sector see panel C22 C22 C22 C22 C22 (SECTOR AVERAGES).
• RA RA RA RA RATIOMETRIC CONTROL TIOMETRIC CONTROL TIOMETRIC CONTROL TIOMETRIC CONTROL TIOMETRIC CONTROL
In this mode the user has to specify for each program the quantity of each
fertilizer to be dosed. The quantity can be specified in volume or in weight
of active substance. All these settings are made in panel S41
S41 S41 S41 S41 (RATIOMETRIC
CTRL). If the volume is set Y, the proportion is dosed for each fertilizer as
volume of fertilizer solution in volume of irrigation water. If the volume is
set to N, the weight of active substance is specified together with the con-
centration of fertilizer solution. The controller will dose then the volume of
fertilizer that contains the specified active substance.
• VOLUME CONTROL VOLUME CONTROL VOLUME CONTROL VOLUME CONTROL VOLUME CONTROL
This mode is available only if the program works with irrigation in volume.
The settings are made in panel S42
S42 S42 S42 S42 (FERT VOL CTRL). Here is specified
the volume of fertilizer solution and the volume of irrigation water in which
is to be mixed.
PH CONTROL PH CONTROL PH CONTROL PH CONTROL PH CONTROL
pH control is necessary to correct and maintain the pH of irrigation water
within specified range: pH reference minus or plus dead band value.
The pH control also has a dead band and a proportional band. These
values are set using panel S36
S36 S36 S36 S36 (pH CONTROL).
The value of pH sensor and the reference value are displayed on panel
C05
C05 C05 C05 C05 (pH STATE).
pH sensor value is displayed also on panel C03
C03 C03 C03 C03 (SENSORS STATE) and in
C01 C01 C01 C01 C01 (GENERAL INFO).
pH control will generate a pH alarm if for a period of time (more than the
time specified using panel S36
S36 S36 S36 S36 (PH CONTROL)) the pH is not within the
specified range. Given a pH alarm condition, pH control can be main-
tained if “Ctrl on PH alarm” is selected using panel number S54
S54 S54 S54 S54 (ALARM
BEHAVIOR). Also given a pH alarm condition, irrigation can be main-
tained if “Irrig on PH alarm” is selected using panel number S54
S54 S54 S54 S54 (ALARM
BEHAVIOR).