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17.7 iCAN Network
For complete information on setting up an iCAN network, refer to CAN Networks tutorial by visiting the
IMO websites.
17.7.1 ICAN Network Troubleshooting Checklist
1.
Use the proper Belden wire type or equivalent for the network.
2.
The I3N does not provide 24VDC to the network. An external voltage source must be used.
3.
Check voltage at both ends of the network to ensure that voltage meets specifications of
attached devices.
4.
Proper termination is required. Use 121
Ω
(or 120
Ω
) resistors at each end of the network. The
resistors should be placed across the
CAN_HI
and
CAN_LO
terminals.
5.
Measure the resistance between CAN_HI and CAN_LO. If the network is properly wired and
terminated there should be around 60
Ω
.
6.
Check for duplicate node ID’s.
7.
Keep proper wires together. One twisted pair is for V+ and V- and the other twisted pair is used
for CAN_HI and CAN_LO.
8.
Make sure the baud rate is the same for all controllers on the network.
9.
Assure shields are connected at one end of each segment -- they are not continuous through
the network.
10.
Do not exceed the maximum length determined by the baud rate and cable type.
11.
Total drop length for each drop should not exceed 6m (20’). A drop may include more than one
node. The drop length adds to the overall network length.
12.
Network should be wired in "straight line" fashion, not in a "star" pattern.
13.
In applications requiring multiple power supplies, make sure the V- of all supplies is connected
together and to earth ground at one place only.
14.
In some electrically noisy environments it may be necessary to add repeaters to the network.
Repeaters can be used to add additional nodes and/or distance to the network and protect the
signal against noisy environments.
