VEGA VEGABAR 55 Foundation Fieldbus - Manual (Page 53)

53
10 Supplement
VEGABAR 55 • Foundation Fieldbus
36736-EN-130321
Electrical protective measures
Protection rating
Ʋ Housing, standard IP 66/IP 67 15)
Ʋ Aluminium and stainless housing
(optionally available)
IP 68 (1 bar) 16)
Ʋ Process component in IP 68 version IP 68 (25 bar)
Ʋ External housing IP 65, IP 66/IP 68 (0.2 bar)
Overvoltage category III
Protection class II
Approvals
Instruments with approvals can have different technical data depending on the version.
For that reason the associated approval documents of these instruments have to be carefully
noted. They are part of the delivery or can be downloaded under www.vega.com via "VEGA Tools"
and "serial number search" as well as via "Downloads" and "Approvals".
10.2 Information on Foundation Fieldbus
Block diagram, measured value processing
The following illustration shows the Transducer Block and Function block in simplified form.
t
i
Simulat
e
ALARMS
Out PV
FIELD-VALUE
Mode & Status PVF-TIME LO
W
-C
UT
O
FF
L-TYP
E
OUT-SCALE PV-SCALE DIRECT
INDIRECT
INDIRECT
SQRT
bar % Lin%
Primary
Value
Secondary
Value 1
Secondary
Value 2
Sensor mounting
correction
AI 2
AI 3
AI 1
TB
Temperature
Sensor_Value
Linearization adjustment
Channel = 1: Primary Value
Channel = 2: Secondary Value 1
Channel = 3: Secondary Value 2
Channel = 4: Temperature
Fig. 28: Transducer Block VEGABAR 55
TB Transducer Block
AI Function Block (AI =Analogue Input)
Diagram, adjustment
The following illustration shows the function of the adjustment:
15) Instruments with gauge pressure measuring ranges cannot detect the ambient pressure when submerged, e.g.
in water. This can lead to falsification of the measured value.
16) Only with instruments with absolute pressure ranges.