Operation; Fault Monitoring; Fault Output - Pepperl+Fuchs H-System Manual

H-System – Isolated Barriers and Termination Boards

Operation

5 Operation
Danger!
Explosion hazard from live wiring of non-intrinsically safe circuits
If you connect or disconnect energized non-intrinsically safe circuits in a potentially
explosive atmosphere, sparks can ignite the surrounding atmosphere.
Only connect or disconnect energized non-intrinsically safe circuits in the absence of a
potentially explosive atmosphere.
Danger!
Explosion hazard from sparking when using operating elements
Using operating elements in a potentially explosive atmosphere can cause sparks that can
ignite the surrounding atmosphere.
Only use operating elements (e. g., switch, slider, button, etc.) in the absence of a
potentially explosive atmosphere.
5.1

Fault Monitoring

Numerous faults can occur between measurement of the process variable and evaluation in
the control system. This can lead to undesirable process statuses under certain
circumstances. These process statuses may result in plant downtime or quality problems
or even present a hazard to persons and the environment. Depending on the device version,
the isolators enable monitoring of the following faults:
• Line faults
Here, the connection cables between the isolator and field device are monitored for lead
breakages or short circuits. If a fault is detected, it is output at the fault message output
or collective fault message. The relevant switching outputs are then switched to a 
de-energized state. The red fault indication LEDs signal the fault.
• Device faults
The isolators are designed so that internal faults are detected and reported. In the case
of a power failure, the outputs are switched to a de-energized state.
5.2

Fault Output

Several H-System isolators monitor the field cables for lead breakages and short circuits so
that faults in the plant can be detected immediately. Line faults are prevented from being
interpreted as signals.
Depending on the configuration of the devices, these faults are transmitted to the outputs at the
control side and in separate fault indication outputs as additional information.
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