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Universal Measuring Device UMG 500A
Iw >= P
Calculation of the pulse valence:
Iw:
Pulse valence
[Wh/pulse]
P:
M a x i m u m
expected real power [kW]
Work pulses
Output of real or reactive work presents a special case. In this case, a proportional analogue signal is not
provided, but pulses, whose frequency is proportional to the real or reactive power. The analogue output thus
behaves like a metering pulse sender. The pulse valence is set via scaling of the analogue output in Wh (varh)/
pulse. This can be selected between 1 and 9999 in steps of 1 Wh (varh)/pulse.
The maximum pulse frequency of the analogue output is 0.25 Hz, i.e. one pulse in four seconds. If the power
exceeds the maximum pulse frequency, the surplus of pulses are stored and will be transmitted later, if
possible. In this case, the momentary pulse duration does not represent the momentary power.
Example 1:
The maximum pulse valence is to be calculated for a
three-phase network for which P = 500 kW.
Iw >= P
Iw >= 500 kW
This indicates that the pulse valence must be set equal
to or bigger than 500, if the maximum pulse frequency
of 0.25 Hz should not be exceeded.
0..20mA
Analogue output
Allocation
In order to allocate a particular measuring function to the output, the desired measuring function
and the measurement phase must first be selected. After this, the function set is allocated to the
analogue output by operating the keys illustrated on the left.
Scaling
The analogue output can be scaled for any quantity to be measured, independently of the choice of display
function. The object of this scaling is to make maximum use of the range 0 (4) to 20 mA in order to achieve
the largest possible resolution of the measured value, without going outside the scale. The setting range of
the scale value depends on the function selected, and can therefore vary from function to function. (see table
Functional plan.
The data in brackets applies to devices fitted with a 4 .. 20 mA analogue output.
Attention: If real power is assigned to a 4 .. 20 mA analogue output, the output current will decrease below
4 mA in case of generating mode.
.. / 5A
Example 2:
A pulse receiver can only evaluate a pulse valence
of maximum 1500 Wh/pulse.
Iw
>=
P
1500 >=
P
The maximum power which can be evaluated is
1500 kW.
0..20 mA
