Siemens SIMATIC NET Manuel page 169

1. Functional description
The Industrial Ethernet™ OSM has 4 ITP-
Ports (10 Mbit/s) and 2 F/O-Ports (100
Mbit/s). As required, a terminal device or a
subnetwork with several terminal devices
can be connected to each port.
1.1 SWITCHING FUNKTIONEN
Store and Forward (Frame-Switching)
All data packets received by an OSM are
saved and their validity is tested. Invalid
and faulty data packets and fragments are
rejected. An OSM only passes on valid data
packets, the forwarding of faulty data
packets is prevented.
Learning addresses
An OSM independently learns (by evaluati-
on of the source addresses in the data
packets) the addresses of terminal devices
connected via a port and enters these in an
address table.
Only data packets with
– these destination addresses or
– a multi-/broadcast address
in the destination address field are sent to
this port. This results in the decoupling of
load between the subnetworks linked by an
OSM.
Data packets with unknown destination
addresses are sent to all ports.
An OSM can learn up to 8000 addresses.
This is required when more than one termi-
nal device is connected to one or more
ports. Thus several independent subnet-
works can be connected to the same OSM.
Deleting addresses
An OSM monitors the age of learned
addresses. Address entries exceeding a cer-
tain age (300 seconds), are deleted by the
OSM from its address table.
Note: A reboot results in learned addresses
being deleted.
1.2 REDUNDANT COUPLING OF RINGS
Two Industrial Ethernet™ OSMs can be
connected via the standby port, one of
which is switched to standby mode. The
two OSMs are connected via an ITP-XP line
with a maximum length of up to 40m.
With both OSMs, the ITP XP line is clipped
onto the standby port. One of the two
OSMs is switched to standby mode via the
DIP switch.
Pairs of OSMs can used for redundant swit-
ching between OSM or OLM rings at a data
rate of 10Mbit/s (see Fig. 7).
An error is recognized and rectified within
0.5 seconds.
1.3 INTERFACES
ITP ports
Four 9-pin sub-D sockets allow four inde-
pendent segments or individual devices to
be connected. The socket casings are elec-
trically connected to the front panel and
thus connected to the housing of the OSMs.
Mechanical locking is by means of a
UNC 4-40 screw locking mechanism.
– Pin configuration of the 9-pin sub-D
socket:
– TD+: Pin 5, TD-: Pin 9
– RD+: Pin 1, RD-: Pin 6
– remaining pins: not configured.
RD+ Pin 1
Pin 6 RD-
n.c. Pin 2
Pin 7 n.c.
n.c. Pin 3
Pin 8 n.c.
n.c. Pin 4
Pin 9 TD-
TD+ Pin 5
Fig. 1: Pin configuration of an ITP interface
ITP ports have following functions:
Link Control
The OSM monitors the connected ITP line
segments for short-circuit or interrupt using
regular link test pulses in accordance with
IEEE standard 802.3 10BASE-T. The OSM
does not transmit any data in an ITP seg-
ment from which it does not receive a link
test pulse.
Note: A non-occupied interface is assessed
as a line interrupt. The ITP line to terminal
equipment which is switched off is likewise
assessed as a line interrupt as the de-
energised device cannot transmit link test
pulses.
Auto Polarity Exchange
If the reception line pair is incorrectly
connected (RD+ and RD- switched) polarity
is automatically reversed.
Duplex mode
Depending on the DIP switch setting the 10
MBit/s ports are in the half or full duplex
mode.
State of delivery is half duplex mode
(default of SIMATIC NET communication
processors).
The 100 Mbit/s ports are always in full
duplex mode.
F/O ports
Two optical ports to 100BASE-FX (BFOC/2,5
(ST) sockets) enable to configure a
100 Mbit/s backbone.
According to IEEE 802.3 standard 100BASE-
FX an OSM monitors the attached F/O lines
for open circuit conditions.
Standby port
A 9-pin Sub-D socket serves for connecting
the ITP-XP line for the redundancy mode.
The socket casing is electrically connected
to the front panel and thus connected to the
housing of the OSMs.
Mechanical locking is by means of a
UNC 4-40 screw locking mechanism.
– Pin configuration of the 9-pin sub-D
socket:
– Stby_Out+: Pin 5, Stby_Out-: Pin 9
– Stby_In+: Pin 1, Stby_In-: Pin 6
– remaining pins: not configured.
Stby_In+ Pin 1
Pin 6 Stby_In-
n.c. Pin 2
Pin 7 n.c.
n.c. Pin 3
Pin 8 n.c.
n.c. Pin 4
Pin 9 Stby_Out-
Stby_Out+ Pin 5
Fig. 2: Pin configuration of the standby
interface
5-pin terminal block
The supply voltage and the indicator
contact are connected via a 5-pin terminal
block with screw locking mechanism.
Warning!
v
Industrial Ethernet™ OSMs are
designed for operation with SELV.
Only safety extra-low voltages to
IEC950/EN60950/VDE0805 may
therefore be connected to the
supply voltage connections and to
the indicator contact.
– Voltage supply: The voltage supply can
be connected to be redundant. Both
inputs are decoupled. There is no load
distribution. With redundant supply, the
power pack supplies the OSM alone with
the higher output voltage. The supply
voltage is electrically isolated from the
housing.
– Indicator contact: Contact interrupt
indicates the following by means of a
potential-free indicator contact (relay
contact, closed circuit):
– the failure of at least one of the two
supply voltages.
– a permanent fault in the OSM (internal
5 V DC voltage, supply voltage 1 or 2 not
in the permissible range).
– the faulty link status of at least one ITP-
or F/O ports.
The indication of the link state might be
masked on a port-by-port basis using
DIP switches.
– at least one port has auto partitioned.
– selft test error
OSM in normal mode and ITP-XP line
plugged to the standby port.
– short-circuited ITP-XP line.
– partner device runs in normal mode.
OSM in standby mode
– not attached, short-circuited or interrup-
ted ITP-XP line.
– partner device runs in standby mode.
Note: In case of the voltage supply being
routed without redundancy, the OSM indi-
cates the failure of a supply voltage. You
can prevent this message by feeding in the
supply voltage through both inputs.
L1+ +24 V
F1
M
Fault
F2
L2+ +24 V
Fig. 3: Pin configuration of 5-pin terminal
block
1.4 DISPLAY ELEMENTS
Equipment status
These LEDs provide information about sta-
tuses which affect the function of the entire
OSMs.
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