Table of Contents
Advertisement
20
5.6
Regular Maintenance checks
Check the general condition of the installation occasionally to ensure that no
deterioration has occurred. At least every two years (and more frequently for harsh,
dusty or dirty environments) check:
•
the condition of all wire connections/terminations/screens.
•
that all of the fixing and cover screws and blanking plugs are secure and the
breather is clear.
•
that there are no signs of damage or corrosion.
•
that the level of accumulated dust on the enclosure does not exceed 5mm.
In addition, take advantage of plant maintenance shutdown periods or whenever the
area is known to be non-hazardous, to check wiring quality by confirming that the dc
voltage on the fieldbus trunk, when measured at the enclosure, is >16V. This can be
performed using a multimeter or an FBT-6 fieldbus tester.
5.6.1
Proof testing of redundancy mechanism
The Fieldbus Barrier is designed to automatically transfer spurs between the
'active' to the 'standby' barrier modules in the event of internal electronic failures.
This mechanism may be proof-tested by manually forcing the transfer of all spurs
between the modules using the Fail-over buttons located on the module carrier
(see clause 5.2.2 and diagram 5.1). Pressing the A > B button will force all spurs to
transfer from module A to module B. Pressing the B > A button will return the spurs
to module A.
Operating the Fail-over buttons will reliably transfer all spurs without interrupting
the fieldbus communication; however, repeated operation is not advised if the
Fieldbus Barrier is operating in a live fieldbus segment. Use of the Fail-over buttons
is therefore recommended only for periodic proof-testing during plant shutdowns,
and for the purpose of module replacement.
Operation of the Fail-over buttons will not cause active spurs to be transfered
to a missing or failed barrier module.
6
Troubleshooting
The Redundant Fieldbus Barriers are fitted with LED indicators to assist the user
in fault identification.
Consult the following tables to understand the meaning of the LED states.
Power LED (Green)
The Fieldbus Barriers inside the enclosure are fitted with LED indicators to assist the
user in fault identification. Consult the following tables to understand the meaning of
the LED states.
The Power LED will not light until the voltage at the barrier has risen to a value
of at least 15.7V, but could remain lit even after the voltage has dropped to
around 13.0V. DO NOT assume the Power LED indicates a voltage of 16V or
more.
Power LED
Colour
Green ON steady
Green OFF
NOTE
NOTE
Description
Trunk power present
Insufficient or no trunk power
Visual
INM 9370-RD Rev 5
Advertisement
Table of Contents
