User Guide

ManualsBrandsHanna Instruments ManualsSensorsHI 7871

• Subsequently, when liquid level drops below the 3

bar, OVER LED goes off and HIGH LED comes on. When

liquid level drops below the 2

bar, HIGH LED goes off.

LOW LED lights up when the level drops below the 1

bar.

• HI 7873 can also detect faulty conditions, such as a

short or open circuit, in the 2-wire connection between

#8 and #9 terminals with HI 7874 bar holder.

If the 2-wire is shorted, the OVER LED

goes on and the alarm contacts close.

If the 2-wire is damaged and the circuit

is open, LOW LED goes on and the alarm

contacts close.

• With HI 7871, LOW LED goes on with an

open circuit. If the LOW LED remains lit

but the pump/electrovalve is not acti-

vated, it indicates an open circuit.

A short circuit will instead give a HIGH

LED indication.

Note: It takes about 8 seconds for the controller to activate

the relay from when an alarm condition occurs.

ACCESSORIESACCESSORIES

ACCESSORIES

HI 7164 11-pin connector

HI 7875/P Sensing bars, 5 pcs, 50 cm long (1.5’)

Note: The sensing bars are made in such a way that they

can be screwed into each other to provide any

required length. It is recommended to keep the bars

separate with a non-conductive material such as

plastic to ensure they do not touch each other,

specially in deep tanks.

• Turn on the power supply. After approx. 8 seconds, the

controller can activate a pump or electrovalve.

• When liquid level is below the COM (reference) or the 1

bar, LOW LED turns on and output contacts (#4 &

#5) close, activating a pump/electrovalve:

• When liquid level reaches the low (1

) bar, LOW LED

goes off but the contacts (#4 & #5) remain closed:

• When liquid level reaches the high (2

) bar, HIGH LED

turns on and the output contact (#5) opens (pump/

electrovalve disactivated) while #3 & #4 close:

• With HI 7873, if after reaching HIGH level, liquid level

continues to rise and reaches the 3

bar, the alarm

contacts close and the OVER LED comes on:

OPERATIONAL GUIDEOPERATIONAL GUIDE

OPERATIONAL GUIDE