Siemens SITRANS FX300, Operating Instructions Manual, Page: 34 / 80

4
ELECTRICAL CONNECTIONS
34
SITRANS FX300
www.siemens.com/flow 06/2009 - SFIDK.PS.050.F2.02 A5E02100423
4.3.1 Power supply
The required supply voltage can be calculated using the formula below:
U
ext.
= R
L
* 22mA + 14V
where
U
ext.
= the minimum supply voltage and
R
L
= the total measuring loop resistance is.
4.3.2 Totalizer / pulse output
The basic units for the totalizer and the pulse output are m m m m
3
33
3
for volume,
m
m m
m
3 33 3
norm.
norm. norm.
norm. for standard volume and kg
kg kg
kg for mass.
The unit and the conversion factor can be changed in menu item 3.2.8 "Conf.Tot". User specific
units (User Def.) can also be entered but the conversion factor must always be entered based on
the base unit. For a sample calculation see chapter 6.2.5 "Change units".
The maximum frequency of the pulse output is 0.5 Hz.
INFORMATION!
The supply voltage has to be between 14 VDC and 36 VDC. This is based on the total resistance of
the measuring loop. To determine this, add up the resistances of each component in the
measuring loop (not including the measuring device).
INFORMATION!
The power supply has to be able to supply a minimum of 22 mA.
Figure 4-3: Pulse output
1
f
max
≤
0.5 Hz
2 closed
3 open
4 Pulse
≥
250 ms
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