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sven-bertil-carlsson avatar image
sven-bertil-carlsson asked

Use of terminators with Lynx Shunt/Cerbo GX

Hi! I have installed Lynx Shunt - Lynx Distributor - Cerbo GX and added MultiPlus, Smart Shunt and a NMEA2000 adaptor. The Lynx Shunt included two terminators and it's manual stated that one should be inserted into the unused port. Where should the other be inserted? Into the Cerbo GX? According to the reseller no one should be used since I have N2K connected, which already has terminators. Is this correct? To me, I find it strange since it is a different network.

cerbo gxlynx shunt
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Kevin Windrem avatar image
Kevin Windrem answered ·

VE.Can and any CANbus extensions are terminated at both ends of the entire length of the bus. So where the terminations go depends on how things are connected.

In a simple system with just the Cerbo and Lynx Shunt, one termination plugs into each device with the RJ-45 cable connecting the two devices.

If you extend the but with a CANbus adapter then multiple taps to various devices, then one termination will PROBABLY plug into Cerbo with the other termination supplied on the end of the CANbus trunk. This would assume you looped from Cerobo to Lynx Shunt to CANbus.

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sven-bertil-carlsson avatar image
sven-bertil-carlsson answered ·

I have connected according to the picture. If I connect the VE. Can > NMEA2000 adaptor to Cerbo GX I have no room for any terminator on the Cerbo. 20230728-210152.jpg


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Kevin Windrem avatar image
Kevin Windrem answered ·

You should use a separate tap for Cerbo and the Lynx Shunt off the N2K bus. Keep the VE.Can cables less than the CANbus spec for max tap length.

Otherwise, rewire so VE.Can goes to one end of the N2K bus in place of that end's terminator then terminate at the Lynx Shunt.

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sven-bertil-carlsson avatar image
sven-bertil-carlsson answered ·

The second part I understand and make sense, unfortunately it is very difficult and takes a lot of time to do (one end of the N2K is up on the flybridge and the other at the lower helm and the Cerbo is low in the stern, in the middle of the N2K backbone) so... the first part sounds more interesting. What do you men with a separate tap? Is it a special T of some sort?

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Kevin Windrem avatar image Kevin Windrem commented ·
Just use two taps and two VE.Can to CANbus adapters right next to each other on the backbone.

You may get away with it the way you have drawn it but the length of ethernet cable to reach both Cerbo and Lynx Shunt may exceed the specs for stub length.

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