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16
5.2.1
Fitting and removal techniques
The individual 9377-FB-R Redundant Fieldbus Barrier module(s) may be fitted or
removed without isolating the trunk power. The trunk connections to the barrier
module on the carrier have spark suppression by design and cannot cause ignition
while they are being connected or disconnected. This section should be read to
understand the physical removal or installation of a barrier, but read 5.2.2 on
page 16 to understand the recommended procedure for replacing a barrier when
powered.
5.2.1.1
Removing a Fieldbus Barrier module (refer to Figure 5.1)
a) Loosen the three captive fixing screws (C & D) on the module to release it. The
screws are all spring-loaded and should retract when the thread has disengaged.
b) Slowly pull the 9377-FB-R Fieldbus Barrier module away from its connections on
the carrier until the safety retaining clip (B) stops further removal.
c) Press the clip (see bold black arrow) towards the module until the barrier is
released and can be removed completely.
5.2.1.2
Fitting a Fieldbus Barrier module (refer to Figure 5.1)
Note: Before fitting a 9377-FB-R Fieldbus Barrier module check the connection pins
on its underside to ensure that they have not been bent or damaged in any way.
Do not use, or attempt to repair, a barrier module that has any of its pins bent or
damaged, because this might affect its safety and will invalidate the certification.
a) Engage the locating guides (A) of the 9377-FB-R Fieldbus Barrier module into the
sockets provided on the carrier and push the module fully into place.
b) Tighten the three captive fixing screws (C & D) to a recommended torque of
0.9Nm to secure it.
Fail-over
button
A
B
Figure 5.1 - Fieldbus Barrier module – fitting & removal
5.2.2
Use of Fail-over button when replacing a barrier
The following technique is recommended for the replacement of a barrier. Do
not remove the 'active' barrier of a redundant pair as this may cause loss of
communications to a fieldbus device.
Two fail-over button are provided to permit a manual transfer of control status from
Active to Standby e.g. A > B or B > A. By switching all spurs to a fully operative
barrier module, 'active' operation can be maintained during module replacement.
The following example illustrates a typical "hot-swap" procedure.
C
D
C
A
B
INM 9370-RD Rev 5
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