IMC CANSAS - Page 45

CAN-Bus description 45
imc CANSAS Users Manual - Doc. Version 1.9 - 05.12.2014© 2014 imc Meßsysteme GmbH
Practical notes on measuring
The DC-voltages apply with an operating voltage of 12 V.
These voltages are guideline values and can deviate by a few multiples of 100 mV.
No additional measurement instruments such as an oscilloscope, etc., may be used at the same
time.
1. Possibility – the CAN-Bus is working correctly
Bus
CAN_H
CAN_L
CAN_L - GND
CAN_H - GND
CAN_L - CAN_H
Active
OK
OK
3,3 V
1,8 V
1,5 V
Sleep-mode
OK
OK
4,9 V
0,1 V
4,8 V
2. Possibility - CAN_H or CAN_L not connected properly
Bus
CAN_H
CAN_L
CAN_L - GND
CAN_H - GND
CAN_L - CAN_H
Active
not connected
OK
4,8 V
1,7 V
3,1 V
Sleep-mode
not connected
OK
4,9 V
0,1 V
4,8 V
Active
OK
not connected
3,3 V
0,2 V
3,1 V
Sleep-mode
OK
not connected
4,9 V
0,1 V
4,8 V
3. Possibility – short circuit between CAN_H or CAN_L and GND
Bus
CAN_H
CAN_L
CAN_L - GND
CAN_H - GND
CAN_L - CAN_H
Active
at GND
OK
4,8 V
0,1 V
4,8 V
Sleep-mode
at GND
OK
4,9 V
0 V
4,9 V
Active
OK
at GND
0,01 V
0,2 V
-0,2 V
Sleep-mode
OK
at GND
0 V
0,1 V
-0,1 V
4. Possibility – short circuit between CAN_H or CAN_L and SUPPLY
Bus
CAN_H
CAN_L
CAN_L - GND
CAN_H - GND
CAN_L - CAN_H
Active
at SUPPLY
OK
4,8 V
12 V
-7,2 V
Sleep-mode
at SUPPLY
OK
5,4 V
12 V
-6,6 V
Active
OK
at SUPPLY
12 V
0,2 V
11,8 V
Sleep-mode
OK
at SUPPLY
12 V
0,1 V
11,9 V
5. Possibility - CAN_H and CAN_L are connected
Bus
CAN_H
CAN_L
CAN_L - GND
CAN_H - GND
CAN_L - CAN_H
Active
at CAN_L
at CAN_H
2,9 V
2,9 V
0 V
Sleep-mode
at CAN_L
at CAN_H
2,5 V
2,5 V
0 V