User's Manual

ManualsBrandsHanna Instruments ManualsMusical Toy InstrumentHanna Instruments Hanna Instruments HI 9913

SECONDS

2.0 0

PROPORTIONAL SETTINGS

0.5 1.5

In order to optimize the controlling process and reduce the amount of

chemicals and fertilizers used, it is recommended to use a proportional

dosage appropriate for the system.

HI 9913 and HI 9935 allow

for a proportional band (delta)

of 0 to 2.0 pH. They also

allow for of proportional band

of 0 to 2.0 mS/cm and 0 to

400 ppm for conductivity (EC)

and TDS, respectively. Each

controller also provides for two

independent time cycles from

0 to 90 seconds. The propor-

tional dosage is obtained by

personalizing a current pulse

whose height equals the pH or EC/TDS proportional delta and the

length corresponds to the selected time cycle.

The controller will enter

the proportional dosagethe proportional dosage

the proportional dosage at the setpoint

plus or minus the preselected delta. It will then keep the dosing relay

activated for a period proportional to the difference between the

actual measurement less the setpoint over the cycle.

NOTE:

• If the setting is left at 0 pH, the controller will operate as an

ON/OFF control with no proportional dosage. In this case the

controller will operate with a 0.1 pH hysteresis.

• Similarly, if the setting is left at 0 mS/cm or 0 ppm, the controller

will operate as an ON/OFF control with no proportional dosage.

The hysteresis of such an ON/OFF control will be 0.1 mS/cm or 15

ppm, respectively.

•

Do not set the time cycle to 0Do not set the time cycle to 0

Do not set the time cycle to 0. This causes the relay to

chatter and can be detrimental to your controlling system and

pump.

• Remember to select the “ALK” (alkaline) or “ACID” dosing direc-

tion (see 4 - Functional Diagram) before setting the pH proportional

control. If you are to reduce the pH, choose “ACID” and inversely,

switch to “ALK” to increase the pH level (HI 9913 only).

PROPORTIONAL CONTROLPROPORTIONAL CONTROL

PROPORTIONAL CONTROL

(HI 9913 & HI 9935)(HI 9913 & HI 9935)

(HI 9913 & HI 9935)

SECONDS

2.0

PROPORTIONAL SETTINGS

0.5 1.5

SECONDS

ppm

400 0

PROPORTIONAL SETTINGS

100 300