CAN BUS LOOP

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volvo780
Newbie
Posts: 1
Joined: Wed Sep 11, 2019 10:02 pm

CAN BUS LOOP

Post by volvo780 » Wed Sep 11, 2019 10:11 pm

If we remove a computer module from the bus, i.e disconnect the computer connector, will the rest of the bus operate as normal. Do we have to substitute a 120 ohm resistor for the removed computer module or can we just put a wire loop on the CAN bus terminals of the connector on the BUS side.

Can we just leave the removed connector hanging with no resistor or loop? and then work with the bus in that condition reading the connected modules that are left?

Iver
TwoWaves
TwoWaves
Posts: 117
Joined: Mon May 27, 2019 2:55 pm

Re: CAN BUS LOOP

Post by Iver » Mon Sep 16, 2019 12:21 am

Do we have to substitute a 120 ohm resistor for the removed computer
Yes, it is wise to do so. As long as you KNOW that the module you removed has the 120 ohm resistor stitched in to it.

If not then NO !!
or can we just put a wire loop on the CAN bus terminals of the connector on the BUS side.
No you cant short anything that way, lucky for you that CANbus has 10kohm resistors to protect it from shorts to Ground & Positive. That is what makes it suitable for medical use as well as automotive. It is robust and resilient to most abuse.

Do you have an understanding of why the resistors are there ? The Egg must exist before the Chicken ?

Just to pre-empt your next question, which might be "who laid the Golden Egg" then that would be Bosch, Siemans & Alan Tong in no particular order, all pioneers ! :D :D :D

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