Pepperl+Fuchs H-System Manual page 10

H-System – Isolated Barriers and Termination Boards
Product Specifications
2.2.2 Status Indications of the Isolators
LEDs are often used on isolators to indicate different statuses (e. g. for power supply, device
failure, status messages, binary switching states). Standard LED colors are assigned to the
status indication according to NAMUR NE44.
LED Display function
Green LED Power supply
Red LED Device fault, device failure
Line fault
No fault
Yellow LED Switching states of binary
inputs and outputs
Table 2.1 Meaning of status indications
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Display Meaning
On Power supply OK
Off No power supply or insufficient power supply –
device faulty
On Internal fault signal, failure signal – fault/failure
display of causes detected inside the device,
device needs replacing
Flashing External fault signal, failure signal – fault/failure
display of causes detected outside the device,
inspection and elimination of fault required
Off No malfunction, device is operating properly
On Possible causes of the output:
• The relay is energized.
• The NO contact (also a change-over contact)
is actively closed.
• The open collector is switched through.
• The switching voltage generated inside the
device is applied.
Possible causes of the input:
• A binary switching signal is present.
• An analog limit value is reached.
Off Possible causes of the output:
• The relay is de-energized.
• The NO contact (also a change-over contact)
is actively opened.
• The open collector is not switched through.
• The switching voltage generated inside the
device is not applied.
Possible causes of the input:
• A binary switching signal is present.
• An analog limit value is reached.