ATI
PQ45P pH System
Part 4
– Electrical Assembly
12
O&M Manual
Rev-B (7/15)
3.3
Battery / Power Circuit Board
PQ45P monitors are normally powered by internal C-cell alkaline batteries or by an external
power connection. Figure 6 shows this board assembly with batteries installed. Figure 7 shows
the same board with terminals installed for external power connection.
The battery circuit board contains 3 switch assemblies as shown in the drawings.
The first
(S1)
is an On/Off slide switch. This switch must be in the ON position for operation.
Turn it to OFF if you do not intend to operate the monitor in the next week or two.
The second switch assembly
(S2)
contains two switches, the one on the left marked LOCK and
the one on the right marked MODE. The function of these two slide switches are as follow:
LOCK
This switch is used to define how the monitor will turn on and off. This switch is
normally in the OFF position. With the lock switch off, the monitor will be turned
on manually using the MENU key on the front of the monitor. With the lock
switch in the ON position, the monitor will always be on when there is enough
power to run the monitor. The ON position is normally used when operating from
an external power supply intended for continuous operation.
MODE
This switch is used to set the voltage at which monitor will shut off when powered
by internal batteries. Alkaline batteries can normally be run down to about 0.75
volts. However, the monitor can be operated using rechargeable nickel-metal
hydride (NiMH) batteries as well. This type of battery should not be discharged
below about 1 volt before recharging. When using alkaline batteries, the mode
switch is in the OFF position (factory default). If rechargeable NiMH batteries are
substituted, place the MODE switch in the ON
position. Note that rechargeable
NiMH batteries have only about 35% of the capacity of an alkaline C-cell, so
Figure 6 - Battery Circuit Board w/C-Cell Batteries
