ONICON F-3100 MOD User Manual

Page 12

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F-3100-MOD Flow Meter Network Interface Installation Guide 05/14 - 0725-1

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SECTION 3: NETWORK TROUBLESHOOTING TIPS

3.1 TROUBLESHOOTING

REPORTED PROBLEM

POSSIBLE SOLUTIONS

Device will not communicate

with the network controller.

• 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 1.5 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.)

• 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 the F-3100.

• 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 1.6.2 of this manual for details.)

Network communications are

disrupted when the device is

connected.