Hanna Instruments HI 9912 User Manual

Page 9

CONNECTIONS & WIRING

ELECTRODE WITH
BNC CONNECTION

WIRING ACCESS

PORTS

MATCHING PIN FOR GROUND PROBE

GENERAL POINTS

• The relay terminals

relay terminals

relay terminals of the controller are powered

powered

powered. You can

simply hook up your pumps or electrovalves directly to the
controller and do not need additional power supply.

• Unscrew the 4 screws on the right hand panel and remove the

cover and the gasket. Thread the wires through the access ports
on the right hand side of the controller.

• Before

Before

connecting the controller to the mains, wire

the controller completely

the controller completely and make all the connections for
pumps, alarm, electrode, set the alarm threashold and adjust
the settings. Upon completion replace the cover

replace the cover

replace the cover. Only then

connect the controller to the power supply.

ELECTRODE & GROUND PROBE CONNECTIONS

• Simply attach any combination pH and ORP electrode with a

male BNC connector (such as HI 1002/3 and HI 2002/3) to the
female BNC sockets located on the bottom of the casing and twist
them into a secure position.

• HI 9912 also provides for Ground Probes (differ-

ential input) to reduce electrical noise and
interference. The controller is shipped with the
Matching Pin and Reference terminals shorted (see 14 and 15 -
Functional Diagram). If you are not using a matching pin
(ground probe), leave the terminals shorted

leave the terminals shorted

leave the terminals shorted and skip the

next two paragraphs.

• It is recommended that only electrodes that incorporate a match-

ing pin (such as HI 1003/3 and HI 2003/3) are utilized. In this
case simply attach the 4-mm banana connectors of the

attach the 4-mm banana connectors of the

matching

matching pins to the sockets

pins to the sockets

pins to the sockets located next to the BNC

connectors on the outer casing (see 24 and 26 - Functional