Author Topic: SHIELDS  (Read 1440 times)

Offline dlewis

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SHIELDS
« on: December 14, 2023, 08:33:45 PM »
Is it NESSASARY to connect the CANbus shield to the shield pins on the controllers and displays?  What are the consequences of not doing so?  I'd like to use the shield pin as an analog input on all my controllers.

Offline Lukey

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Re: SHIELDS
« Reply #1 on: December 14, 2023, 11:35:31 PM »
It is not necessary, that is why the Pin can be used as an Input.

I have used the CAN Shield Pin as an input many times without issue or consequence.

Offline FluidPowerTom

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Re: SHIELDS
« Reply #2 on: December 15, 2023, 04:59:31 PM »
The consequences of not hooking it up are that the CAN bus is less robust to electromagnetic interference.  If your CAN bus is relatively short this is maybe not a big deal at all.  If your CAN bus stretches out over the boom of a crane then I'd recommend terminating the CAN cable shield to ground so as not to risk com errors.
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Offline spittet

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Re: SHIELDS
« Reply #3 on: December 18, 2023, 06:37:01 PM »
Usually, you would need to ground a shield at only a single end of a bus. It doesn't need to be grounded at a device, it's just more convenient to do so for wiring simplicity.

If you want to use the shield pins of your controller and still keep your shield grounded, simply ground it somewhere else, near the end device of a bus. Do this for each different buses.

Sam

Offline Marbek_Elektronik

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Re: SHIELDS
« Reply #4 on: December 21, 2023, 07:35:01 PM »
I think, J1939 bus is to connect in the middle and only one time?

But it is normally so, that shields have to connect at the end and tho the boxes and the boxes are not connected to ground or via capacitor.
But this is in industrial applications.

In mobile applications every box ist grounded.
But ground is not equal ground and maybe there is a ground current in shield!
I think, every case is individually. To stop current on shield, use capacitors or connect it on only one point.

You EMV-tester can tell you more about this.
Marbek Elektronik, Dipl.-Ing. Bernd Konrad
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