KROHNE VFM 5090 EN - Manual (Page 53)

Part D VFM 5090(I) Ex
9. Description of the system
The compact version of Vortex Flow meter VFM
5090(I) is suitable for operation in potentially
hazardous area. The Ex version is housed in a
Flameproof PDC enclosure approved by PTB. The
complete instrument is designed in protection
categories :
EEx d[ib] IIC T2..T6 & EEx de[ib] IIC T2..T6
Signal converter housing(Electronics compartment)
Flameproof enclosure "d"
as per EN 50014, EN 50018
Signal converter housing (Terminal compartment)
Standard Increased safety "e"
As per EN 50014, EN 50019
Optional Flameproof enclosure "d"
As per EN 50014, EN 50018
Sensor circuit with integral barrier
Intrinsic safety "ib"
As per EN 50014, EN 50020
9.1 VFM 5090(I) Ex Earthing connections
The compact version of VFM 5090(I) must be
grounded ensuring equipotential bonding.
Connect equipotential bonding conductor PA to a
separate earthing stud with screw-clamp fixed on the
neck of the Flameproof enclosure.
Connection of the earth conductor in power cable
should be terminated to earthing stud in Terminal
compartment of the flameproof enclosure.
9.2 Electrical connection
The power cable and signal cable should be routed to
the terminal compartment through separate cable
glands for field connections.
The cables should have at least 9mm (0.35”) outer
diameter ensuring firm holding of cables and sealing
in the cable glands. Refer Diagram given for field
connections.
FIELD CONNECTION DIAGRAM
10. Process Pressure and Temperature
Nominal pressure is indicated on the nameplate
riveted on the Instrument.
Process temperature and option of Distance piece
between Primary Head and Signal Converter
determine the temperature class of the product
operated in hazardous area.
With Distance piece
Without Distance piece
Temp.
class
Max.
medium
Temp.
Temp
class
Max.
medium
Temp.
T6 80 0 C T6 80 0 C
T5 95 0 C T5 95 0 C
T4 130 0 C T4 130 0 C
T3 150 0 C T3 180 0 C
T2 240 0 C
11. Replacement of electronics in signal converter
Important
· Switch off the mains power.
· Ensure that there is no explosion hazard.
· Ensure that all the cables are disconnected and
isolated from the supply.
· Allow waiting time to lapse before opening the
enclosure.
The time limit is mentioned on the nameplate for
different temperature classes as:
42 minutes for temperature class T6
5 minutes for temperature class T5
0 minutes for temperature class T4..T2
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