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CAN bus always needs a resistor to shunt it (termination)?
zenerbjt:
Do you agree that even if you are only using a CAN bus to port a simple low frequency signal such as eg a low frequency PWM (speed control signal) being sent to an 3 phase BLDC inverter …then you still need a termination resistance shunting the CAN bus?
We are using the TCAN332 CAN transceiver.
TCAN332 CAN tranceiver:
https://www.ti.com/lit/ds/symlink/tcan332.pdf?ts=1597868220681&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTCAN332%253Futm_source%253Dgoogle%2526utm_medium%253Dcpc%2526utm_campaign%253Dasc-null-null-gpn_en-cpc-pf-google-eu%2526utm_content%253Dtcan332%2526ds_k%253DTCAN332%2526dcm%253Dyes%2526gclid%253DEAIaIQobChMI6MPP9Yqo6wIVT-3tCh0Sbg_lEAAYASAAEgJymPD_BwE%2526gclsrc%253Daw.ds
oPossum:
4 out of 5 dentists agree that CAN bus should be terminated at each end.
poorchava:
You do, regardless of the number of nodes.
Aside from stuff like reflections, which may not be a problem is your lines are short, termination acts as a lossy element that can dissipate differential mode interferences, which may be a really serious problem, especially that you're working with a motor drive, which is typically a very noisy device.
I generally tend to place small value resistors in series with data lines to help dampening any random oscillations and noise that may get coupled to the line.
rvalente:
AFAIK, you not need only one but, two 120ohms terminations, at the begin and end of line.
This is the same for 485 (modbus), profibus DP and CAN
uer166:
With no termination you will fail transmission due to arbitration failure. The transceivers need termination to work properly to pull bus to recessive state, nothing to do with reflections/SI.
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