2 General Functions
2.2 Operating mode related functions
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Version 04 05/2014
The operating mode is set using switches located on the
front of the repeater. A sticker attached to the side of the
repeater provides assistance with the settings.
Caution:
The OZD Profi 12M … PRO must be switched off when
switching over DIL switches.
Segment monitoring at the RS 485 channel
If the operating mode ”Electric channel with segment
monitoring“ is set, each receiver monitors the RS 485
bus segment connected to it for faulty frames or conti-
nuously busy networks. If faulty frames are received by
the receiver, or if the network is busy for longer than the
maximum permitted send time, forwarding of the received
signals is blocked until frames can be received again
correctly, or if no signal is received for one second.
The RS 485 bus segment is not monitored in the opera-
ting mode ”Electric channel without segment monitoring“.
Interference from the electrical segment affects the entire
network.
Please observe the installation notes in 4.7 ”Connecting
the electric RS 485 bus lines“, p. 30.
The following functions are only available for the optical
channels. Whether the functions can be activated
depends on the operating mode which has been set.
Please refer to the following chapters for details.
Line monitoring with echoes
The repeaters enable the connected optical paths to be
actively monitored for interruptions in the fiber line by
means of the functions ”Send echo“, ”Monitor echo“ and
”Suppress echo“.
Send echo
A frame which is received by a repeater via any channel
is transmitted to all other channels. If the receiving chan-
nel is an optical channel, the repeater sends the frame
back to the corresponding optical sender.
Monitor echo
If a repeater sends a frame - no echo! – to an optical
channel, the repeater expects to receive an echo. If the
echo is not received after a predefined time, an echo
monitoring error is indicated by a red LED belonging to
the channel.
Suppress echo
The relevant receiver is separated from the other chan-
nels from the moment a frame is sent until the echo has
been received correctly.
Segmentation
If an echo monitoring error or a frame falsification arises
at an optical channel, the repeater assumes that the line
is faulty and blocks this channel for user data. The
connected field bus partial network is then segmented
(cut off). This segmentation causes the repeater at the
other end of the optical fiber to be segmented as well.
Both repeaters connected to the segmented field bus
partial network send test frames to the segmented
channels. These test frames – which are to be received
regularly – can be used by both repeaters to check the
status of the field bus partial network.
The segmentation is automatically lifted as soon as the
test frames indicate to both repeaters that the segmen-
ted field bus partial network is no longer disturbed.
If all active bus subscribers are deactivated in a
previously active network, the repeaters are segmented
cyclically in order to check the fiber links to the neigh -
boring repeaters. If there is no frame traffic, but the fiber
links are intact, the channel LEDs of the optical channels
flash yellow cyclically.
2.2 Operating mode related functions