User manual

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MC-III™ EXP Flow Analyzer Section 2
Internal Power Supply
The MC-III EXP is shipped with one of three internal power supplies:
• a CSA-approved 3.6V lithium battery
• an ATEX-approved 3.6V lithium battery
• a shrink-wrapped alkaline battery pack containing three C-size industrial-grade batteries (available only
with CSA-approved devices)
Low-power microprocessor technology enables the MC-III EXP analyzer to operate approximately 2 years on
a single lithium battery. The lithium battery is strongly recommended for use in extreme temperatures (below
-20°C).
Users can power the instrument from an external power supply or a 4-20 mA current loop, and use the lithium
or alkaline battery (where applicable) as a backup power supply. The use of an alternate power source extends
battery life and helps ensure that timekeeping and volume accumulation will not be interrupted during a
power failure.
External Power Supply
The MC-III EXP can be connected to a remote power supply by a two-conductor cable (Figure 2.8). The
power supply and cable must be capable of supplying 6 to 30 VDC @ 10 mA. This capability is available
only if the 4-20 mA rate output is not used.
A Zener diode (Part No. 1.5KE33CA) must be installed for CE approval.
Caution: When using the amp & square output with the external power supply, make sure the
power supplies for both features share a common negative (-) terminal or that they are
totally isolated from each other, since both share a common negative (-) connection.
T
B
3
TB1
PULSE
INPUT
RESET
INPUT
TFM
A&S
GND
EXT POWER
TB2
RS485
SLAVE
4-20
OUT
PULSE
OUT
6-
3
0
V
D
C
POWER
SUPPLY
6 to 30
VDC
J1
J2
RESET
SWITCH
BATTERY
TB3 MARKINGS:
GND = SIGNAL GROUND
Figure 2.8—External power supply wiring