Hanna Instruments HI 8000 Series - Manual (Page 9)

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sectors using one of the following ways:
- Manually
- Every day at specified hour
- Automatically when the accumulations counter value overflows
3.2 CONDUCTIVITY CONTROL
Conductivity control is used to control the fertilization and a reading can be
obtained with one to three conductivity sensors, one to two for fertilization control
and one for water supply conductivity control.
When using two conductivity sensors, the second for safety, the maximal admis-
sible difference between these two sensors can be set using panel S 55 (SEN-
SORS CONFIG).
A third conductivity sensor can be used to measure the conductivity of the water
supply.
Conductivity sensor (S1 main, S2 second and S-for water input) status and
conductivity reference are displayed on panel C 05 (EC STATE). In addition, the
main conductivity sensor value is displayed on panels C 01 (GENERAL INFO)
and C 02 (SENSORS STATE);
Solar radiation accumulation setting and current value for conductivity reference
correction is displayed on panel C 07 (SOLAR RAD FERT).
The conductivity control is made in accordance with a preset conductivity refer-
ence value, specific for each irrigation program. In addition, the conductivity
reference has a minimum offset and maximum offset. The reference value, mini-
mum and maximum offset can be set using panel S 41 (COND CONTROL).
When the conductivity is not within the specified range for a period of time (more
than the time specified) or the difference between the 2 primary conductivity
sensors is greater than the specified difference, the conductivity control will gen-
erate a conductivity alarm . Specified difference can be set using panel S 55
(SENSORS CONFIG). The conductivity alarm threshold can be set using panel
S 41 (COND CONTROL). “EC Out of Range”-the conductivity alarm can also
be generated when the EC IN sensor’s value exceeds the specified EC sensor
difference.
Given a conductivity alarm condition, conductivity control can be maintained if
“Ctrl on EC alarm” is selected using panel number S 52 (ALARM BEHAVIOR).
Statistical values of total conductivity are displayed on panel C 22 (TOTAL AV-
ERAGES). For each irrigation program’s conductivity average see panel C 23
(PROGRAM AVERAGES) and for each individual sector’s conductivity average
see panel C 24 (SECTOR AVERAGES).