Installation, Operation and Service Manual
LKP Series 4 Channel OEM
© 2019 DynAmp, LLC
Page 22
041593O
With unidirectional LKP measurement systems, it is possible that the AD circuits will give a
warning indication when the system is operated at low rectifier current level, even though all
circuits and components are functioning properly. This warning at low levels is most likely to
occur if the metering system is associated with one of several rectifiers in the area.
The AD outputs indicate the present condition, having only a short time delay from an
instantaneous condition. Although the AD does not monitor every possible error condition, it is
an effective means of giving the user continual assurance of signal reliability.
A.
If the “Diagnostics Relay” is O.K. and the green LED indicators are all on: Continue
operating normally.
B.
If the “Diagnostics Relay” indicates a warning and one or more green indicators are
off:
This indicates there may be measurement errors and consequently, the metering system
should not be in full, automatic control of the rectifier. The AD relay contact output is not
intended to be the only monitor protecting the power rectifiers. Primarily, it is expected that the
customer wants to take immediate action to prevent unsafe operation. Unsafe operation could
result if the metering system is in the rectifier control loop and it erroneously produces a
significantly lower output than is true. This might cause the rectifier control circuit to
inappropriately increase the power output, perhaps to overload levels for either the power
supply or the process. So, if the metering system is in the control loop and the “Accuracy
Diagnostics” indicates a potential problem, the following actions are recommended: FIRST-
Lock out control actions that could drive the rectifier output higher and SECOND-alert the
operator.
Basically, each module inside the Metering Unit has four channel LEDs and two power supply
monitoring LEDs. The following is a description of their functionality:
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 within 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.
The primary current is too low to activate all channels properly;
b.
A blown channel fuse;
c.
A bad connection between the cable and the Metering Unit or cable and
Measuring Head;
d.
A bad Hall device in the Measuring Head;
e.
An open /or shorted coil in the Measuring Head;
f.
A strong external magnetic field causing a channel reversal;
g.
A primary current that exceeds the dynamic measuring range of the Metering Unit.
