Tecfluid XT5 - Manual (Page 18)

7 MAINTENANCE
No special maintenance is required .
For cleaning, a humid cloth can be used, and if necessary with a little soap. Solvents or
other aggressive liquids which could damage the housing (polycarbonate) should not be
used.
7.1 Fuse
In the event that the fuse blows, this should be replaced with a slow blow “T” fuse, size
Ø5 x 20 mm and of the same rating as indicated on the label inside the equipment.
8 EXAMPLES OF USEFUL CALCULATIONS
8.1 Measurement error correction
The calibration of flow meters is made with water at 20 o C, obtaining a calibration for a
liquid density of 1 kg/l and viscosity of 1 mPa·s. If the flow meter is used with a liquid of
other characteristics from the above specified or for reasons of turbulences in the flow,
measurement errors can be induced.
To correct these types of errors we can modify the value of the Fc factor programmed in
the instrument.
Example - Shortage of volume
If we have a flow meter body which specifies Fc = 0.985, and when we check the volume
of a batch, we find that instead of having 100 litres as programmed, we only have 95 litres
(5% less), then the following correction must applied:
Fc = Original sensor factor = 0.985
V = Expected Volume = 100
Vr = Real Volume = 95
Fcn = New sensor factor = ? (1.037)
8.2 Configuration of pulses / unit of volume
As indicated in the point 3.2.3, the maximum frequency of the pulse output in mode
pulses / unit is 6,25 Hz. In order to know if the desired number of pulses per unit of
volume can reach this frequency, the following formula can be applied:
Where
fmax = Maximum frequency at the output
Flow rate
max
(u/s) = Maximum flow rate in units of volume per second
F
p/u
= Factor of pulses per unit of volume programmed in the converter
Example - Sensor DN 25 and programmed Factor = 100 pulses / litre
Firstly, we need to know what is the maximum flow rate that could pass through the flow
meter. For example 9500 litres / hour.
Changing the flow rate to units of volume per second we obtain:
Note that the units of volume are litres because in this example the programmed factor is
100 pulses / litre.
V
V F
= F
r
c
cn

18
p/u max max
F (u/s) rate Flow f  
second / litres 2.639 3600 / 9500 