88TK50/R1210
7
Disturbance annunciations on the module
On the module front, the following disturbances are indicated
by red LEDs:
LED designation
--- Disturbance, general
ST
Types of disturbance 1 ... 3
--- Module disturbance of 88TK50
SG
Type of disturbance 1
--- Processor halt
HLT
--- Disturbance of ring redundancy
SR
Light---emitting diode ST indicates all disturbances of the
module and disturbances of the data communication with the
module.
After three undisturbed station cycles, light---emitting diode ST
goes off.
Furthermore, ST is illuminated for approx. 20 sec when the
module is being initialized or when the 88TK50 has discon-
nected a disturbed module from the station bus.
Light---emitting diode SG indicates module disturbances only.
Furthermore, SG is illuminated for approx. 20 sec when the
module is being initialized.
Light---emitting diode HLT indicates that the FDDI system inter-
face has stopped data transmission from and to the FDDI ring
because of an internal error. Data transmission of the other
stations in the FDDI ring is not affected in this case.
Light---emitting diode SR indicates that the FDDI ring redun-
dancy is either disturbed or no longer present.
Status messages on the module
The following operating states are indicated by green LEDs on
the front panel:
LED designation
--- FDDI receiving
FE
--- FDDI sending
FS
--- Start of station cycle
SZ
--- Station---bus communication
SV
--- Station---bus modules
ER
with events
Light---emitting diode FE is illuminated when telegrams are be-
ing transmitted on the station bus and received via the FDDI
ring.
Light---emitting diode FS is illuminated when telegrams of the
station are being transmitted over the FDDI ring.
Light---emitting diode SZ is illuminated for approx. 100 msec
when a new station cycle starts.
Light---emitting diode SV is illuminated when the send tele-
grams of the station are being transmitted over the station bus.
Light---emitting diode ER is illuminated from the moment when
events have been detected until the event telegrams are being
transmitted.
Receive monitoring
The receive monitoring function on the 88TK50 monitors the
data received from the FDDI for faulty FDDI frames. If the
receive monitoring function responds, the fault flag contained
in each frame will be set.
This fault flag is processed by the sending 88TK50.
A frame with event telegrams will be repeated, if necessary,
twice.
In the case of a frame with cyclic telegrams, the frame with the
current data of the station will be regenerated and transmitted,
if necessary, twice.
The 88TK50 indicates the disturbance by entry ”Acknowledge-
ment error” (60/246/bit 8 or 61/246/bit 8) in its diagnosis regis-
ter.
Monitoring of ring redundancy
The monitoring of the ring redundancy monitors the proper
functioning of both optical rings of the FDDI rings. If the moni-
toring function responds, only one of the optical rings is still
operational.
This status is indicated on the module front by red LED ’SR’.
ATTENTION!
When red LED ’SR’ is illuminated:
--- No station coupled directly to the FDDI ring may be
switched off,
--- No 88TK50 coupling module may be withdrawn,
because this would cause an interruption of the only optical
ring that is still operational.
Based on the disturbance annunciations, the cause for the ring
interruption must be identified and eliminated.
The cause could be a failure of the cabinet voltage supply, a
defective 88TK50 module or a defective optical cable.
