H-System – Isolated Barriers and Termination Boards for HIMA
Product Specifications
20
16-11
17
2.5
Status Indicators with LEDs
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 display according to NAMUR NE44.
LED
Display function
Display
Meaning
Green LED
Power supply
On
Power supply OK
Off
Power failure or insufficient power supply
–
device faulty
Red LED
Device fault, device
failure
On
Internal fault signal, failure signal
–
fault/failure
display of causes detected inside the device,
device needs replacing
Line fault
Flashing
External fault signal, failure signal
–
fault/failure
display of causes detected outside the device,
inspection and elimination of fault required
No fault
Off
No malfunction, device is operating properly
Yellow LED
Switching states of
binary inputs and
outputs
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.
Table 2.1
Meaning of status indicators
