Endress+Hauser PROline promag 53 - 4.4 Potential Matching

Proline Promag 53 FOUNDATION Fieldbus
26 Endress+Hauser
<
0
If, in the example examined, the condition L
eff.
< L
o
is met, then the demonstration of
intrinsic safety with respect to the electrical parameters has a positive result. In this
example, however, the condition was not met since the bus line selected is too long.
Possible solutions:
1. Reduce the main line by 175 m to 405 m (this can be achieved by installing the bar-
rier in the immediate vicinity of Explosion Zone 1, for example).
2. Check under what conditions the manufacturer of the safety barrier or segment con-
nector allows the use of the L/R ratio for technical safety considerations.
Since all the users are permissible for explosion group IIC and the corresponding
parameters have been taken into consideration, the bus segment can be used for gases
in explosion group IIC.
The permissible ambient temperature may be considered either individually for each
device at the respective place of installation, or specified uniformly for the bus segment
as a whole. In the latter case the lowest value of the ambient temperature applies.
Intrinsically safe equipment
Promag 53
Condition Associated equipment
MTL 5053
Condition met?
Total capacitance
C
eff.
= 115.6 nF
< perm. capacitance for IIC
C
o
= 165 nF
✓ Yes
Total inductance
L
eff.
= 423.1 µH
< perm. inductance for IIC
L
o
= 320 µH
No
Tab. 6: Safety considerations (example)
Required temperature class Intrinsically safe equipment Maximum ambient temperature
T6
Cerabar S 40 °C
Promag 53 50 °C
(at 80 °C medium temperature)