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It is suggested to download testing software MODSCAN for MODBUS-RTU
communication protocol from our homepage. This software adopts standard
MODBUS-RTU protocol which can display data in the formats such as integer, float
and hexadecimal, so that you can compare the data with measured data displayed
on the meter directly.
7.2 Measurements about U, I and P are incorrect
First make sure that the meter has been input right voltage and current. The
multi-meter is used for measuring voltage and current, and the clip-on meter is
used for measuring current signal. Second make sure the signal wire is connected
correctly, for example the dotted terminals of current signal (i.e. inlet) as well as
the phase sequence of each phase should be correct. Observe power display
interface of the meter, and its power symbol is displayed positive under normal
condition and negative only when it is under reverse transmission which is caused
by wrong connection of inlet-outlet lines or wrong phase sequence connection.
What’s more, electric quantity displayed on the meter is the value of primary grid;
it may lead to wrong electric quantity display if the ratio of voltage and current
transformer does not conform to that of transformer in-service. The defaulted
voltage and current range is not allowed to be modified after delivery. Connection
network is available to be modified according to actual connection on spot, but the
connection mode set in programming shall correspond with the actual connection
method, otherwise it may lead to wrong display.
7.3 About incorrect power running
Energy is accumulated on the basis of power measurement; check whether power
value displayed is consistent with actual load. As the product supports bidirectional
energy measurement, energy will be accumulated to backward energy instead of
forward one if wires are not connected properly or total active power is negative.
The most common problem on spot is inlet and outlet wire of current transformer
are in reverse connection. Observe signed active power in split phase, and it may
be negative because of wrong connection, and what’s more, wrong phase
Summary of Contents for Sfere720A
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