ELKOR TECHNOLOGIES INC.
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MCM
–
USER MANUAL
Nodes are "hot-pluggable," meaning that they can be installed or removed even while the device is powered, allowing for
metering to continue un-interrupted even when the configuration is changed.
Each node corresponds to three current inputs. Each current input must be paired with a voltage input during setup. Any
current channel on any node can be paired with any voltage channel.
2.6.
Current Inputs
Standard wiring principles for electricity meters apply to the WattsOn-MCM, as for any other electricity meter.
The polarity
of interfacing transformers must be observed. The upper terminal of each current input connector is always associated
with the 'X1' wire of the coresponding CT, with the lower terminal corresponding with the 'X2' wire. Please refer to
(p. 39) for details.
All mV and mA CTs must be wired independently to the corresponding current inputs (two wires from each CT without
shunts or jumpers).
mA and mV CTs must
NOT
be grounded, or interconnected with each other (or any other
components) in any way.
A CT shorting mechanism is not required for mV and Elkor mA style CTs, since these are voltage clamped, however
appropriate protection (fuse or breaker) for input line voltages is required.
2.7.
Voltage Inputs
The four input terminals on the bottom of the WattsOn-MCM-V, on the bottom-right of the WattsOn-MCM, are voltage
inputs, with the rightmost terminal being the neutral line. Line-to-line voltages of up to 600V may be present on these
lines, so proper electrical safety procedures should be followed during installation and maintenance according to local
codes.
Line voltages of up to 600V line-to-lne on the WattsOn-MCM-V terminals are isolated from the rest of the WattsOn-MCM's
components, and from the output ports.
2.7.1.
Fusing of Voltage Sensing Inputs
The input voltage lines should be protected as per electrical code requirements. This is also good practice to facilitate an
easy disconnect means for servicing the meter. In some cases, the voltage may be tapped off of existing fuses or
breakers. If this is not possible, Elkor recommends a 1A or lower fuse (fast acting) for protection of the installation wiring.
The WattsOn-MCM voltage inputs are high impedance (> 1.5M
Ω
) and draw negligible current (less than 0.3mA max).
2.8.
Power Supply
The WattsOn-MCM is powered by a 10W, 100-240VAC (input) power supply which is DIN rail mounted next to the isolator.
This power supply outputs 24VDC to the motherboard, from which each component is powered. The power supply also
provides 4kVAC isolation between the input (100-240VAC) and the output (24VDC). While this DIN rail power supply may
be replaced with an external 24VDC source, considerations for grounding and power requirements should be observed.
The power supply inputs may be shared with the metering lines provided that the measurement voltage is within the 100-
240VAC specification. If there is no voltage within the 100-240VAC range available at the installation location, contact
Elkor Technologies Inc. for options.