Westermo ODW-632 - Manual (Page 9)

9 6650-2253
Designed for harsh environments, such as industrial,
road and railway applications
ODW-632 complies with standards for industrial environments and railway signalling and
telecommunications apparatus. Additionally, the wide climatic range of the ODW-632
allows it to be installed in out-door cabinets without any additional measures, such as
heating, etc.
Redundant ring via fibre optical network
Under normal operation the serial data is sent over ring A. Should a fault be detected on
the fibre ring then the data will be carried on rings A and B.
TX RX TX RX TX RX TX RX TX RX TX RX TX RX TX RX
Master, unit Slave, unit
CH 2 CH 1 CH 2 CH 1 CH 2 CH 1 CH 2 CH 1
Ring A
Ring B
M S
PLC PLC
Ring A Ring A Ring A
Ring A
Ring B Ring B Ring B
Ring B
Note! Ring A start up at TX (channel 1) and ring B ends up at RX (channel 1).
… Normal operation, data exchange between serial master and slave.
• ODW-632 unit connected to the PLC-master receives serial data at the electrical
port, it converts and transfers this master frame via the fibre ring A. At this unit the
repeating of transferred frames is stopped until this transferred master frame has
returned via ring A.
This master frame will be repeated through fibre ring A by all the other units. Each
of these units will also convert the master frame to serial data and send it via the
electrical port.
• ODW-632 unit to which the addressed Slave is connected, receives serial data from
the Slave. This unit converts slave data and transfers the slave frame via ring A.
The repeating of transferred frames is stopped until this transferred slave frame has
returned via ring A.
• When the “first” ODW-632 unit receives the master frame (the same frame that has
been transmitted by this unit), or after a timeout, data conversion at will be allowed
again. The received slave frame will be converted and transmitted at the electrical
port.