CAN ISSUE

[farooq_niaz]

I am assembling old quad with DIMU and ESC32. Using QGC1.4 B1 CAN MOT_L is 15 and CAN_MOT_L is 0. ESCS are programmed with r54. Given CAN ID 1,2,3,4 to ESCs.

I had made a CAN cable with 120 resistor at one end. One DIMU I soldered 120 on empty R3 spot.

When I try to arm the ESCs they are not arming. I have not connected power to the ESCs motor side. Each ESCs microcontroller is being powered by 5V from the autoquad's 5V and Ground.

When I try to get resistance from two can terminals (ESCs or DIMU). I am getting very low value of resistance around 1 ohm. I had checked that escs were arming when I use them in PWM mode.

if i disconnect dimu and measure the resistance when all esc are connected to can wire with one end of the wire terminated with 120ohm resistor the resistance is 0.9 ohm.

With dimu not connected the resistance is on R3 on dimu is 120 Ohm???
strange

[bn999]

You have a short somewhere on the bus. Check the CANL/CANH pads on each ESC individually.

[farooq_niaz]

Ok found issue.

One of the ESCs CAN header is giving some short circuit around 1 ohm.

When I isolated this ESC and put it on pwm all esc start to arm afterwards. I think the CAN chip is bad.

Now the bus is giving 40 Ohm impedance which is lower than 50 ohm limit. What else should i look for.

Need advice from Jussi as this is a very new ESC and still on the bench.

[chschmid]

[farooq_niaz]

I have one connected on cable and one i soldered on dimu at r3

[Jdmagoo]

[farooq_niaz]

I cut the 120 resistor on the cable. Now with 120 Soldered on the R3 position on DIMU and three ESC connected in parallel to the DIMU on CAN bus impedance is 60Ohm


But the fourth ESC is now showing open circuit on the CANL and CANH pins.