Elis FLONET FH30xx Series, Инструкции по управлению

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ELIS PLZEŇ a. s.
Project design, installation and service manual
Page 20 o
f
33
Electromagnetic flowmeters of the type series
FLONEX FXx11x and FLONET FH30xx
Meter control instructions
ELIS PLZE
Ň a. s., Lucni 425/15, 301 00 Plzeň, Czech Republic tel.:+420 377 517 711, fax:+420 377 517 722
Es 90 686 K
In selecting the impulse number, the following conditions shall be met:
Qmax
≤ 3.6 × V × fmax
(m3/h, l/imp, imp/s)
Where: Q
… fluid flow rate
(m
3
/hour)
V
… fluid volume per impulse
(l)
P
… impulse width
(s)
f
… impulse output frequency
(Hz)
T
… cycle length
(s)
Volume V per impulse is usually selected from the options shown in the following table:
V (l)
0.001 0.01 0.1 1 10 100 1,000 10,000
In cases of electronic determination of the fluid volume passed through the sensor, the impulse
width is recommended to be set at P
min
= 5ms, which meets the condition for f
max
at the impulse
output equal to 100Hz. In cases of electro-mechanical counters, P
min
is usually set at 50ms,
corresponding to the maximum frequency at the impulse output of 10Hz.
Example:
Assume that a user specified for their flowmeter of DN100 the maximum operating flow rate:
Q
max
= 150 m
3
/h (Q
max
= 41.
66 l/s … v = 5.3 m/s)
For the fluid volume corresponding to one impulse (of length 5ms, f
max
100Hz) it holds:
By selecting the next higher impulse number from the above table (1 litre per impulse) the user will make
sure that the impulse output frequency will not exceed (for the specified Q
max
of 150 m
3
/hour) the value of
100Hz and, at the same time, verify the selection of the impulse length (5ms). The user may choose the V
values other than those from the basic selection in the above table, e.g. 0.5 litres/impulse.
Should the volume flow rate and the aggregate volume passed through the meter be given in units
outside the SI system (e.g. US gallons), the fluid volume per impulse should be converted to litres
using the table in section 5.1.4.2.2. The parameter of fluid volume per impulse shall then be
determined with respect to the maximum frequency at the impulse output and the type of
measuring system used.
P + M = T f =
1
T
V

Q
max
(litres/impulse, m3/h, Hz)
3.
6 × f
max
V

0.416
(litres/impulse)