Installation, Operation and Service Manual
LKAT Plus EMC
© 2018 DynAmp, LLC
Page 5
047331 A
The outside of the Metering Unit enclosure includes four receptacles for external connection
to the Measuring Head, the Metering Unit measurement signal(s) and relay outputs, and the
input of mains power. When properly mated with the associated cable assembly, these
connections are also environmentally protected. External power for the Metering Unit is
“universal input” type: 85 to 264Vac @ 47 to 440Hz, or 110 to 264Vdc. Wiring changes are
not required
for any supply voltage in this range. Burden on the supply circuit will not
exceed 30VA.
Internally, all LKAT Plus Metering Units include both a power supply and a Main pc board.
These 2 PC boards are mounted to a steel chassis which is then mounted on a steel panel
housed in the enclosure. The Metering Unit enclosure door has a window made of clear
polycarbonate. This allows the user to view various LED (or LCD) status indicators while the
door is closed. For more information, refer to the “Theory of Operation” section of this
manual.
There are two optional pc board assemblies that may be added onto the Main PC board in
the LKAT Plus Metering Unit:
•
The Protection Extensions (PE) pc board assembly
•
The Display pc board assembly.
One or both of these pc board assemblies may be added to an LKAT Plus Metering Unit in
the field. It is not mandatory that they be factory installed and/or calibrated. The optional pc
board assemblies may be calibrated on site, using the LKAT Plus Main Output as the
reference measurement.
2.4
ADDITIONAL INDICATOR AND OUTPUT DETAIL
As noted on the specifications page, the LKAT Plus System Metering Unit includes several
visual indicators. These include:
•
Accuracy Diagnostics (operational status) LEDs: green = OK, red = system problem (see
Section - “Theory of Operation”).
•
Over / Reverse Current Trip status LEDs: green = measured current does not exceed the
setpoint, red = measured current exceeds the setpoint. (Optional) Illuminated LCD digital
display of measured current.
Available via the Metering Unit output cable:
•
Isolated signal output proportional to bus current being measured. This output may be
configured for various zero and full-scale values.
•
Normally open and normally closed relay contacts indicate Accuracy Diagnostics (AD)
operational status (same as green and red LEDs).
•
Normally open and normally closed relay contacts indicate over / reverse current trip
status (same as green and red LEDs). For failsafe operation, the relay coil is energized in
the normal condition (no over / reverse trip).
The table below lists the features associated with the Main and PE pc board assemblies:
Table 2.1
Main and PE PC Board Assembly Features
Main PC Board
Assembly
with PE PC Board
Assembly
Isolated Output
1
1
Operational Status LEDs & Relay Contacts
1
0
Overcurrent / Reverse Trip Status LEDs & Relay
Contacts
1
2
