4
PRELIMINARY EXAMINATION
Remove the instrument from the packing material and exam-
ine it carefully to make sure that no damage has occurred
during shipping. If there is any noticeable damage, please
contact your local Hanna Instruments Office.
Note
Save all packing materials until you are sure that the instru-
ment functions correctly. Any damaged or defective items
must be returned in their original packing materials together
with the supplied accessories.
GENERAL DESCRIPTION
The product is a real time microprocessor-based pH/ORP
controller. It provides accurate measurements, flexible
ON/OFF, proportional or PID control capabilities and dual
alarm signals.
The system is composed of a case inside which the signal
conversion circuitry, the microprocessor circuitry and the
output power drivers are contained.
MAIN FEATURES OF DIFFERENT MODELS
• Display: large LCD with 4 ½ 13 mm digits and 3 ½ 7.7
mm digits.
• LEDs: three (
HI22
) or four (
HI21
) LEDs are provided for
signaling the energizing of relay 1 (a yellow LED), relay
2 (a yellow LED in
HI21
Series only) and alarm relays (a
green and a red LED).
• Relays: Electromechanical type, working through NO,
COM and NC contacts; 1 or 2 output relays for acid or
base dosage; 1 output relay for alarm condition.
• RS485 isolated communication link.
• Calibration and Setup procedures allowed only through
an unlock password.
• Calibration: for
HI21
series at 1, 2 or 3 points with
pH4.01, 7.01 and 10.01 buffers; for
HI22
series in 1
or 2 points at 0, 350 and 1900 mV.
• Temperature compensation of the Hanna Instruments
standard buffers (for
HI21
series only).
