Installation - Hanna Instruments HI21 Series Instruction Manual

INSTALLATION

HI21 and HI22 offer
a multitude of possibili-
ties, from single and dual
setpoints to ON/OFF,
proportional or PID dos-
age, isolated outputs with
user-selectable zoom,
bidirectional RS485, re-
corder outputs in mAmps
and Volts.
In addition, HI21 and
HI22 are both equipped
with the exclusive differen-
tial input.
In a system with poor
grounding, it is possible
to have a ground cur-
rent flowing through the
reference junction. This
can cause a rapid deg-
radation of the electrode.
The Hanna Instruments
differential input reduces
the likelihood of ground
loops.
See the diagram for a rec-
ommended installation.
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