ADS Environmental Services Model 3600 530002 A2 - Manual (Page 24)

Hardware 2-9
when connecting the SCADA EMU to an AC power source using the ADS power
cable with the three-prong wall plug transformer, make sure the power source is earth
grounded.
Note: Customers using their own power cables must pin the SCADA EMU
connector according to the diagram displayed on the inside cover of the
SCADA EMU to ensure proper earth grounding.
In the event of power loss, the NiCad battery, located in the EMU, can provide
operating power for the 3600 flow monitor. The NiCad battery has been sized to
provide about six to eight hours of operation when the flow monitor is taking readings
once per five minutes and when the RTU is polling the monitor once per five minutes.
External DC Power Source (optional)
The EMU will also operate from a user supplied 12 Vdc power source. This power
source should be provided with some form of battery backup that is sufficient to
power the 3600 flow monitor during power outages. The external power source
should provide from 11.5 V to 15.0 Vdc and a voltage ripple of 100 mV peak to peak.
The user supplied power source should be able to support the EMU and 3600 flow
monitor at a maximum of 450 mA although only 290 mA is typically needed for the
required time period. No internal battery backup exists in this configuration. The
cable for this configuration is different from the AC powered configuration. The
following SCADA EMU DC power cable is available for use in the United States or
Internationally:
ADS Part Number External DC Power Cable
P/N 106132A United States or International
This cable is 20 m (8 ft) long, with a 25 m (10 ft) wire to provide earth ground for the
intrinsic safety barriers. The appropriate connector for mating this cable to the EMU
is provided at one end of the cable. The bare end of the cable connects to the DC
power supply [white wire to +12 V, black wire to ground(
−
)].
Earth grounding is necessary to satisfy the intrinsic safety requirements of an
installation involving a 3600 and SCADA EMU using external power. Therefore,
when connecting the SCADA EMU to a DC power source using the ADS power cable
with the exposed wires, connect the ground wire to the earth ground associated with
the power source.
Note: Customers using their own power cables must pin the SCADA EMU
connector according to the diagram displayed on the inside cover of the
SCADA EMU to ensure proper earth grounding.
The EMU cannot tolerate external power source voltage dropouts or droops outside
the specified range regardless of duration. The typical external power source would
be a fully charged lead acid battery; however, no internal battery backup exists in this