Hanna Instruments HI 9912, Instruction Manual

10

pH

0

1

2

0

100

200

mV

ALARM

pH

0

SECONDS

mV

200

0

TIMER

MINUTES

90

PROPORTIONAL SETTINGS

1

10

2.5

5

7.5

0

SECONDS

pH

2.0

0

TIMER

MINUTES

90

PROPORTIONAL SETTINGS

1

10

2.5

5

7.5

500

900

CAL

ALARM

ON

OFF

SET

FEED

mV

OFFSET

SLOPE

ALARM

ON

OFF

0.5

1.5

pH

HI 9912

mV

ORP

ALARM

8

SET

FEED

ALARM

6

7

ACID

OXID

700

50

150

SET pH

SET ORP

ALARM

LINE

BL DOSING

PUMPS

pH

0

1

2

0

100

200

mV

ALARM

Diagram) and remove the jumpers

remove the jumpers

remove the jumpers

remove the jumpers

remove the jumpers shorting the matching

pin terminals.

• When using a separate probe for grounding purposes, wire it to

the Matching Pin terminals on the right hand panel and
remove the jumpers

remove the jumpers

remove the jumpers

remove the jumpers

remove the jumpers (see 14 and 15 - Functional Diagram).

NOTE:

NEVER leave the jumper in when
using an electrode with a match-
ing pin. This can shorten the life
of the electrode (reference) drasti-
cally.

ALARM CONNECTIONS

• The operator can select an alarm threshold of 0.0

to 2.0 pH and 0 to 200 mV by turning the alarm
knob (see 13 and 16 of Functional Diagram). The
alarm can be selected as normally closed ("NC") by
connecting the external device to the C and NC
terminals or normally open ("NO") by connecting
the external device to the C and NO terminals.

RELAY CONNECTIONS

• Wire the external devices (pumps or electrovalves) directly  to the

relay terminal strips of the controller (see 18 and 19 - Functional
Diagram). The
terminals are

terminals are

terminals are

terminals are

terminals are
powered

powered

powered

powered

powered and
hence you do not

 do not

 do not

 do not

 do not

need an ex-

need an ex-

need an ex-

need an ex-

need an ex-
ternal power

ternal power

ternal power

ternal power

ternal power
supply

supply

supply

supply

supply for the
pumps or valves.

NOTE:

HI 9912 provides for two separate relays, one for pH and another for
ORP. In order to save on chemicals and due to the slow reaction of
oxidants, the controller incorporates a Consent feature

Consent feature

Consent feature

Consent feature

Consent feature by which

ORP measurements are adjusted 

only after

 pH has been corrected.

The Consent feature makes the pH correction

pH correction

pH correction

pH correction

pH correction the master

master

master

master

master  and the

ORP adjustment

ORP adjustment

ORP adjustment

ORP adjustment

ORP adjustment the salve

salve

salve

salve

salve for a better control.

REMOVE WHEN

USING MATCHING PIN