5
INM F300 rev 6
DRAFT - 09 July 2019
DRAFT - 09 July 2019
5 .3 .1 Ex nA [ic] applications
When the equipment is installed in an Ex nA [ic] application, a trunk-spur partition*
must be installed to segregate the trunk and spur wiring - see Figures 5.4 and 5.5.
* available in packs of five as Part No. F300-A01-5
Partition
Terminator
Trunk
terminal
Figure 5 .4: Trunk-Spur partition
installation
Figure 5 .5: Trunk-Spur partition in
position
Position the partition as shown in Figure 5.4 and locate the fingers into the channels
on the sides of the device body. Press the partition onto the body until the fingers
click into place at the bottom of the case - see Figure 5.5. The channels have different
sizes so the partition cannot be installed backwards.
5 .4 Spur port connections
Each spur port connector provides (+), (–) and cable screen (S) connections. See
section 5.5 for information on cable screen grounding.
Cable screen connections
The ‘S’ screen terminals for the trunk and the spurs are interconnected/commoned within
the F3xx device and should be grounded at only
one point
for the whole segment (i.e. a
single-point ground). The recommended position for that connection is in the control room
close to the power supply at the DCS, or else in accordance with local system practice.
5 .5 Surge protection
Each fieldbus terminal, trunk or spur, on a Megablock can be fitted with an FS32 surge
protector to prevent damage to the internal components. The FS32 uses the same
pluggable connector as the field connector; so the field connector is removed, the
FS32 inserted and the original field connector is fitted to the FS32. See Figure 5.6 &
5.7.
Trunk - F300-BAR
Spur - F312-BAR
M4 ground screw locations
Figure 5 .6
: Typical grounding bars
Figure 5 .7
: With some FS32 modules
