Endress+Hauser PROline promass 83 II2G Manual page 55

PROline Promass 83 FOUNDATION Fieldbus
Endress+Hauser
Configuration example Entity model
Fig. 8 shows the typical structure and the associated components. The field devices are
operated on a segment with the type of protection EEx ia. A galvanic isolator is used for
the transition to the area with explosion risk. Field devices with a lower power consump-
tion, such as the Cerabar S pressure gauge, are supplied via the two-wire line. In con-
trast, the Promass 83 as a four-wire device must be supplied via an local power supply.
Fig. 20: Typical example of a bus connection with a fieldbus power supply of type MTL 5053
1 = DCS with integrated FOUNDATION Fieldbus H1 interface card
2 = fieldbus power supply, model MTL 5053
3 = Promass 83 bus devices for hazardous area
4 = terminator (T) = bus termination
5 = transducer supply
6 = Cerabar S bus devices for hazardous area
Functional considerations
Using the following procedure the functional considerations checks whether the desired
segment structure meets the basic requirements for transmission to the physical layer
in IEC 61158-2.
Step 1 – compilation of the functional characteristic values of the fieldbus components
x Fieldbus power supply MTL 5053:
U = 18.4 V
S
I = 80 mA
S
105 : (source impedance)
R =
Q
x Fieldbus line:
Cable type A
44 : /km (effective resistance per unit length)
R =
WK
max. permissible cable length L
x Fieldbus device Promass 83:
I = 12 mA (basic current)
B
U = 9...32 V (perm. operating voltage)
B
I = 0 mA (fault current)
FDE
I = 0 (< I )
startup B
x Fieldbus device Cerabar S:
I = 10.5 mA (basic current)
B
U = 9...32 V (perm. operating voltage)
B
I = 0 mA (fault current)
FDE
I = 0 (< I )
startup B
= 1900 m
perm.
0
<
19