Hanna Instruments HI 9914 User Manual

Page 9

Water nozzle, Circulation and Feeding pump connection
The Water nozzle, Circulation pump and Feeding pump outputs are
relay type (2A, 240V). Both the

NO (normally open) and NC (normally

closed) contacts are available to the user. If the device is off, the

COM-

MON pin is connected to corresponding NC pin. If the device is on, the
COMMON pin is connected to the NO pin.

• Connect one pin of the source to the

COMMON pin.

• Connect the device between the

NO pin and the remaining source pin.

Alarm connection
The Alarm output is relay type (2A, 240V). Both the NO (normally open)
and NC (normally closed) contacts are available to the user. If the alarm
is off, the COMMON pin is connected to the NC pin. If the alarm is off, the
COMMON pin is connected to the NO pin.

• Connect one pin of the source to the

COMMON pin of the alarm

output.

• Connect the alarm device between the

NO output pin and the

remaining source pin.

Acid and fertilizer dosing pump connection

The pH and EC correction relays (2A, 240V)
have a common pin: if the pH correction
pump is on, the

COMMON pin is connected

to the

pH PUMP pin; if the EC pump is

activated, the

COMMON pin is connected to

the

FERT. PUMP pin.

• Connect one pin of the source to the

COMMON pin.

• Connect the pH correction pump between the

pH PUMP pin and the

remaining pin of the source.

• Connect the EC correction pump between the

FERT PUMP pin and the

remaining pin of the source.

Note: Both pH and EC correction pumps must have the same operating

voltage. The rated power of the pumps can be different.

pin is the same, so that the voltage of the power source has to match the
working voltage of the selected device and both the pH and EC correction
pumps have to work at the same voltage.