Installation, Operation and Service Manual
LKP Series
© 2016 DynAmp, LLC
Page 28
041738 I
A.
Line: This LED indicates whether the supply voltage to the Metering Unit falls
within the specified limit of +10%, -15% of nominal. Significant changes from
these values will cause this LED to turn off and trip the relay.
B.
Hall P.S.: This LED indicates whether the Hall plate supply voltage supply
voltages fall with the specified operating limits. A failed Hall plate power
supply or a line voltage out of specification will extinguish this LED and trip the
relay.
C.
Channel LEDs: Each channel LED indicates the status of the corresponding
channel to aid quick troubleshooting. An extinguished channel LED can be
caused by the following:
a.
A blown channel fuse;
b.
a bad connection between the cable and the Metering Unit or cable and
Measuring Head;
c.
a bad Hall device in the head;
d.
an open /or shorted coil in the head;
e.
a primary current that exceeds the dynamic measuring range of the Metering
Unit;
f.
the primary current is too low to activate all channels properly;
g.
a strong external magnetic field causing a channel reversal.
Notes on items f and g above:
A.) Under certain conditions, external magnetic fields can reverse one or more channels in
the head. The accuracy indicators will show an error in those channels until the bus
current level rises high enough to effectively turn on all channels (2-3Vdc is the
minimum reliable channel voltage). This condition can cause false alarms. For more
information on this, please refer to technical bulletin TEC9908, “Resolving External
Magnetic Field Errors”.
B.) In some installations, when the channel voltages are balanced, the channel LEDs will
remain on, even though the bus is turned down to zero. In this case, the accuracy
diagnostics circuit is in an unstable condition and alarm faults, as indicated by the
channel LEDs, should be ignored. Note that, in general, the Metering Unit’s 0.1%
accuracy is only guaranteed when the primary bus current is above 5% of the full scale
rating of the unit.
A relay contact output is available to connect to a remote warning system. The relay is
closed under normal operating conditions and opens when a fault condition occurs. The
output connections are available via a connector located on the left side of the Metering
Unit. The terminals are designated on the appropriate interconnection diagram. The
terminals are used as follows:
Contact Terminals
Condition
TS2-17,18
TS2-18,19
Open
Closed
Fault condition, zero bus current*, or
Metering Unit turned off
Closed
Open
Normal operation
* See notes above on zero bus current condition.
