Adjustment - Vega VEGADIF 65 Operating Instructions Manual

3 Product description
Functional principle
Voltage supply
12
A metallic measuring cell is used as sensor element. The process
pressures are transmitted via the separating diaphragms and filling
oils to a piezoresistive measuring element (resistance measuring
bridge in semi-conductor technology).
The difference between the acting pressures changes the bridge volt-
age. This change is measured, further processed and converted into
a corresponding output signal.
1
p
1
Fig. 8: Configuration metallic measuring cell
1 Measuring element
2 Overload diaphragm/Middle diaphragm
3 Filling oil
4 Separating diaphragms
p , p Process pressures
1 2
The markings "+" and "-" on the process component in chapter
"Mounting and connection instructions" must therefore be noted when
connecting to the process. The pressure acting on "+" goes positive,
the pressure acting on "-" goes negative into the calculation of the
pressure difference.
4 ... 20 mA two-wire electronics for voltage supply and measured
value transmission on the same cable.
The supply voltage range can differ depending on the instrument ver-
sion. The exact range is stated in chapter "Technical data".
The backlight of the display and adjustment module is powered by
the sensor. The prerequisite for this is a supply voltage at a certain
level. The exact voltage specifications are stated in chapter "Technical
data".
The optional heating requires its own operating voltage. You can find
further details in the supplementary instructions manual "Heating for
display and adjustment module".
This function is generally not available for approved instruments.
3.3

Adjustment

The instrument can be adjusted with the following adjustment media:
•
With the display and adjustment module
•
with the suitable VEGA DTM in conjunction with an adjustment
software according to the FDT/DTM standard, e.g. PACTware and
PC
2
3
p
2
4
VEGADIF 65 • 4 ... 20 mA