Pulse Emission; Accuracy - Kamstrup ULTRAFLOW 54 Technical Description

TECHNICAL DESCRIPTION

8.10 Pulse emission

Pulses are emitted at intervals of 1 second. The number of pulses to be emitted is calculated every second. Pulses
are emitted in bursts with a pulse duration of 2...5 ms and pauses depending on the current pulse frequency. The
duration of the pauses between the individual bursts is approx. 30 ms.
The transmitted pulse signal is the average determination of a series of flow measurements. This means that
during start-up there will be a transient phenomenon until correct flow signal has been obtained. Furthermore, this
brings about a pulse tail of up to 8 seconds in case of sudden hold.

8.11 Accuracy

®
ULTRAFLOW 54 and 34 have been developed as a volume flow sensor for use with energy meters according to
DS/EN 1434. Permitted tolerances in DS/EN 1434 for flow sensors with a dynamic range of 1:100 (q
in Diagram 14. The tolerances are defined for classes 2 and 3 with following formulas:
2 + 02 . 0 ×
Class 2:
3 + 05 . 0 ×
Class 3:
DS/EN 1434 defines following dynamic ranges (q
In connection with accuracies the range from q
adhered to. There are no requirements as to the relationship between q
®
for ULTRAFLOW .
To ensure that the sensors meet the tolerance requirements, DS/EN 1434-5 specifies calibration requirements in
connection with verification of sensors. The requirements for flow sensors are that they have to be tested at
following 3 points:
q ...1.1 x q , 0.1 x q
i i
During testing the water temperature must be 50 °C ±5 °C for ULTRAFLOW
®
For ULTRAFLOW as a cooling meter the water temperature must be 15 °C ±5 °C
Further requirements are that the tolerance of the equipment used to perform the test must be less than 1/5 MPE
(Max. Permissible Error) in order for the acceptance limit to be equal to MPE. If the equipment does not meet this
standard, the acceptance limit must be reduced by the tolerance of the equipment.
®
ULTRAFLOW will typically do better than half of the permitted tolerance according to DS/EN 1434 class 2.
44
q
p
but max. 5 %
q
q
p
but max. 5 %
q
:q
i
p
..0.11 x q and 0.9 x q ...q
p p p
5512-385 GB/02.2014/Rev. H1
): 1:10, 1:25, 1:50, 1:100 and 1:250.
p
to q is defined as max. flow short-term, where tolerances are
s
and q
p
p
®
ULTRAFLOW 54 and 34
:q ) are shown
i p
. See Table 1 for information on q
s
®
as a heat meter.
s