Installation and Maintenance
5.7 LED Displays and Troubleshooting
SIMATIC NET PROFIBUS, Optical Link Module
Operating Instructions, 07/2008, A2B00065774O, Edition V1.5
39
LED display
Possible causes
Signaling
contact
not lit
Transmission rate not detected yet
–
LED
“
System
“
flashes red
- There is no transmitting bus node
- Transmit and receive fiber-optic cables swapped over
-No partner module connected or partner module is not turned on
- Connected partner module is defective
Transmission rate is detected
–
LED
“
System
”
is lit green
- When the mode
“
redundant optical ring
“
is set, the
optical channel operates as standby channel. There is no problem in the OLM
or on the fiber-optic cable.
- If one of the modes
“
bus with fiber-optic link monitoring...
“
is set, no frames are received on the optical
PROFIBUS channel. There is no error in the OLM or on the
fiber-optic cable.
does not signal
flashes yellow
Transmission rate is detected
–
LED
“
System
”
is lit green or flashes red/green
- There is no transmitting bus node (fiber-optic cable connection is ok)
does not signal
lit red
- Transmit and receive fiber-optic cables are swapped over
- No partner module connected or partner module is not turned on
- Connected partner module is defective
- Transmission time exceeded by the connected partner module
- Interruption of a fiber-optic cable
- Fiber optic cable to the partner module longer than permitted
- Loose contact at a fiber-optic cable connector
- Fiber in the fiber-optic cable is loose
- When the channel LED of the two concerned OLMs continues to be lit red
after clearing a fiber-optic cable fault in the redundant optical ring
check that the setting of the parameter HSA described in section 3.3 is correct
signals
flashes
red/yellow
- Periodically occurring error (see above) loose contact at a fiber-optic cable
connector
- Fiber in the fiber-optic cable is loose
- Only one single bus node is connected, which only sends token to itself.
After the activation of a second participant the LED display should stop
signals
Mode
“
bus without fiber-optic link monitoring
”
lit yellow
PROFIBUS frames are received on the optical channel
does not signal
Not lit
- There is no transmitting bus node
- Transmit and receive fiber-optic cables are swapped over
- No partner module connected or partner module is not active
- Connected partner module is defective
does not signal
Lit green
Receiving level adequate, normal operation
lit yellow
Receiving level critical, link power margin reduced
not relevant
CH2, CH3
Level
Lit red
Receiving level inadequate, function not guaranteed
Table 5-1
M
eaning of the LED displays and indication by the signaling contact
5.7.2
Troubleshooting
This section will help you to localize the problem after an error message (LED or
signaling contact). Refer to the description of the LED displays in section 5.7.1.
5.7.2.1
Error display of the System LED
See description of the LED displays in section 5.7.