User Guide
11
10
• HI 931700 and HI 932700 are single set
point dosing controllers for dosing respec-
tively acid or alkaline / reducing or oxi-
dizing products.
HI 931700:
If you plan to
dose acid (e.g. in
hexavalent chromium re-
duction), make an open cir-
cuit between terminals
marked "S1" and "S2" on
the rear panel (description
on page 3).
If you plan to dose base
(e.g. in cyanide oxidation),
short terminals "S1" and
"S2".
HI 932700:
If you plan to
dose oxidants (e.g. in cya-
nide oxidation), make a
short circuit between termi-
nals marked "S1" and "S2"
on the rear panel (description at page 5).
If you plan to dose reduc-
tants (e.g. in hexavalent
chromium reduction), make
an open circuit across ter-
minals "S1" and "S2".
• Set Contacts: these con-
tacts (maximum 2A, 220 V)
are used for connection to
dosing pumps. Use HI
931700 for dosage of acidic
or alkaline reagents, and
HI 932700 for dosage of
oxidizing or reducing re-
agents. Both units act as a
switch for power to the con-
trol element (e.g. pump).
Note: all external cables connected to the
rear panel should end with cable lugs.
S1
S2
C1
C2
S1
S2
S1
S2
S1
S2
• Connect a 3-wire (115 or
230VAC versions) or 2-wire
(15-24VDC version) power
cable to the terminal strip
paying attention to the cor-
rect live, earth and neutral
(115 or 230VAC version)
or positive and negative
(15-24VDC version) termi-
nal connections.
• Connect the pH or ORP
electrode to the BNC con-
nector marked "INPUT
ELECTRODE".
• To benefit from the differential input, con-
nect the proper electrode wire (if avail-
able) or a cable with a potential match-
ing pin (grounding bar) to the relevant
terminal (# 6 at pages 5 and 7).
Note: When it is not possible to immerse
the Potential Matching Pin together with
the electrode in the solution, disable the
differential input by connecting the con-
nection for Potential Matching Pin with
the connection for Electrode Reference
with a jumper wire.
• Recorder Terminals: these
contacts are the output ter-
minals for connection to a
recorder. The output is from
0 to 20 mA or 4 to 20 mA
as indicated and is propor-
tional to the measured pH
or ORP value.
Note: Calibrate the external recorder to be in
accordance with the display reading
(consult recorder manufacturer instruc-
tion manual).
INITIAL PREPARATION
P3
P2
P1
Earth
Neutral
Live
M1
M2