9
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.