ONICON F-5100 MOD Network - Manual (Page 13)

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F-5100-MOD Flow Meter Network Interface Installation Guide 05/14 - 0669-6
Page 13
SECTION 3: NETWORK TROUBLESHOOTING TIPS
3.1 TROUBLESHOOTING
REPORTED PROBLEM POSSIBLE SOLUTIONS
Device will not
communicate with the
network controller.
• Is the Transmit LED on the display 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 1.6.1 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 1.4 of this manual for details.)
• The Baud rate setting must match the network Baud rate. (See
section 1.5.1 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 F-5100.
• 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. This resistor should only be used if
the meter is the last device on the network cable. (See section 1.5.2
of this manual for details.)
Network communications
are disrupted when the
device is connected.
• 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 1.4 of this manual 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 1.6.1 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 F-5100.