Hanna Instruments HI 8050 User Manual

Page 8

panel C19

C19

C19 (SECTOR ACCUMUL). In addition, this panel displays the

valve number assigned with the corresponding sector.
Accumulations erase mode can be chosen on panel S65

S65

S65 (ERASE STATIS-

TICS). The accumulation erase can be performed for all programs and
sectors using one of the following ways:
- Manually
- Every day at specified hour
- Automatically whether the accumulations counter values overflows

FERTILIZA

FERTILIZATION CONTROL

TION CONTROL

Fertilization can be made mixing the irrigation water with 4 types of fertil-
izers from 4 tanks. Dosing of these fertilizers is controlled by conductivity
or by volume (ratiometric or volume). Volume fertilizer control mode is
available only if the program works in volume irrgation mode. In all cases
is available a correction of fertilization with temperature. The temperatures
for correction of fertilization are set in panel S44

S44

S44 (IRRIGATION CORR).

The type of control used for fertilization is selected in panel S37

S37

S37 (FERT

CTRL MODE):

•

CONDUCTIVITY CONTROL

Conductivity control is used to control fertilization based on the conduc-
tivity of irrigation water. A reference for the conductivity is set in S38

S38

S38 (EC

CONTROL) and a prescription for the proportion of fertilizers is set in S39

S39

(SET FERTILIZERS) and the controller will dose the prescribed proportion of
fertilizers in such a manner to keep the EC water within specified range:
EC refernce minus or plus minimum and maximum offset values. In addi-
tion to this mode a differential conductivity control is available (set in S40

S40

(EC DIFF CTRL CFG). In this mode the controller will dose the fertilizers in
a way that the irrigation water will have the conductivity of reference added
with the conductivity of input water. In this way the amount of fertilizer
dosed is the same even if the input water is contaminated with some sub-
stances that produce the rising of EC. Conductivity sensor status and
conductivity reference are displayed on panel C06

C06

C06 (EC STATE). In addi-

tion, the conductivity sensor value is displayed on panels C01

C01

C01 (GEN-

ERAL INFO) and C03

C03

C03 (SENSORS STATE). Temperature reference correc-

tion and input EC are displayed on panel C12

C12

C12 (EC CORRECTION).

The conductivity control is made in accordance with a preset conductivity
reference value, specific for each irrigation program. In addition, the con-
ductivity reference has a proportional band and a dead band that can be
set using panel S38(EC CONTROL). If the difference between setpoint and
the EC of the water is greater than the dead band for a period of time an

This manual is related to the following products:

HI 8060