Hanna Instruments hi 7871 Manual Do Utilizador

MECHANICAL DIMENSIONS

FRONT VIEW

REAR VIEW

SIDE VIEW

73mm

2.87"

79mm

3.11"

42mm

1.65"

49mm

1.93"

FRONT VIEW

95mm MIN

3.74"

76mm

0.25/4mm

0.01/0.160"

79mm

3.11"

ADJUSTABLE
LOCATION
BRACKET

Adjustable brackets (supplied) allow the controller to slide
into the cutout and hold the unit in place. 95 mm (3.74")
is the minimum space required to install the controller with
the cables connected.

FUNCTIONAL DESCRIPTION

1. OVER LED (HI 7873 only)

indicates an overflow condition

2. HIGH LED indicates full tank
3. LOW LED indicates low liquid

level

4. 11-pin Socket

Dear Customer,
Thank you for choosing a Hanna product. This manual will

provide you with the necessary information for the correct

operation of the instrument. Please read it carefully before

using the controller. If you need additional technical infor-

mation, do not hesitate to e-mail us at tech@hannainst.com.
These instruments are in compliance with directives

EN 50081-1 and EN 50082-1.

Remove the instrument from the packing material and
examine it carefully. If any damage has occurred during
shipment, immediately notify your Dealer or the nearest
Hanna Customer Service Center.
Note: Conserve all packing material until the instrument

has been observed to function correctly. Any defective
item must be returned to the Dealer in its original
packing.

PRELIMINARY EXAMINATION

HI 7871 and HI 7873 are 2-wire transmitter level control-
lers designed especially for long distance control of liquid
levels in tanks (e.g. in biological and industrial water
treatment). A complete system should consist of:

• HI 7871 or HI 7873 level controller;
• HI 7874 transmitter and sensor holder;
• HI 7164 11-pin connector;
• 3 or 4 measuring bars.

The level transmitter is basically a molded electrode holder
with 4 sockets to screw in the level sensors. The longest bar
has to be the common electrode and connected to the COM
port. The remaining electrodes can be connected in any
sequence, after cutting them to the required lengths.
HI 7874 contains the completely resinated amplifier circuit
and the 2-wire terminal board. It also comes with a
mounting bracket for quick and easy installation.
HI 7874 uses stainless steel measuring bars and employs 9V
peak to peak A.C. to measure the liquid level. It can be
used in liquids with conductivity greater than 10 µS/cm
(µmho/cm).
HI 7871 requires only 3 electrodes, whereas HI 7873 needs 4.
HI 7871 is a basic high and low level controller. HI 7873
has an overflow alarm control as an additional feature.

GENERAL DESCRIPTION