ONICON System-10 Dualnet - Manual (Page 27)

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System-10 Dual Network Interface Installation Guide 05/14 - 0972-1
Page 27
SECTION 4.0: NETWORK TROUBLESHOOTING TIPS
4.1 TROUBLESHOOTING
REPORTED PROBLEM POSSIBLE SOLUTIONS
Device will not communicate with the
network controller. (RS-485 Output) • The protocol selection dipswitch must be set to the
appropriate network communication protocol being
used on the RS-485 bus. (See section 1.4 of this
manual for details)
• The Baud rate setting must match the network Baud
rate. (See section 1.6.1 of this manual for details)
• Is the Receive LED flashing on the network board?
This LED will flash whenever there is traffic on the
network. If the LED is not flashing, look for an open
network cable. (See Apendix A-2 for details)
• Is the Transmit LED flashing? The Transmit LED will
only flash when the device is responding to a poll.
A unique address is required for each device on the
network. Duplicate addresses will cause some or all
of the devices on the network to quit working. (See
section 1.7 and Appendix A-2 of this manual for
details.)
• The RS485 network cable connections are polarity
sensitive and must be connected the same way on
every device (i.e. + to + and - to -). (See section 1.5
of this manual for details.)
• Shield drain connections should be daisy chained in
the same manner as the signal cables for RS485. The
shield drain wire should be left unterminated at the
end of the cable and connected to earth only at the
network master controller. Shield wires must not be
connected to the RS485 connector on the System-10.
• The maximum number of devices allowed on a
RS485 network segment without a repeater is 32.
Adding more than 32 devices to a single segment
may reduce the transceiver output voltage to a level
that is too low to be distinguished from background
noise on the cable.
• RS485 cable impedance should be matched to a
termination resistor at the end of the cable. ONICON
boards have a jumper selectable 120 ohm resistor for
termination. This resistor should only be used if the
display is the last device on the network cable. (See
section 1.6.2 of this manual for details.)