What end-to-end bus resistance value is typical when terminators are correctly installed?

What end-to-end bus resistance value is typical when terminators are correctly installed?

• A. Approximately 60 ohms.
• B. Approximately 120 ohms.
• C. Approximately 30 ohms.
• D. Approximately 200 ohms.

Answer: (A)

Two 120-ohm terminators are placed at the ends of a NMEA 2000 CAN backbone. When you measure the resistance across the two conductors end-to-end, those two terminators appear in parallel, giving 60 ohms. So, with terminators correctly installed, the typical end-to-end bus resistance is about 60 ohms. If you measure around 120 ohms, one terminator is missing or not properly connected; if you see a much higher value or open circuit, termination isn’t present or the wiring is broken. This 60-ohm figure reflects the effective impedance the network presents across the CAN pair, ensuring proper signal integrity.

Two 120-ohm terminators are placed at the ends of a NMEA 2000 CAN backbone. When you measure the resistance across the two conductors end-to-end, those two terminators appear in parallel, giving 60 ohms. So, with terminators correctly installed, the typical end-to-end bus resistance is about 60 ohms. If you measure around 120 ohms, one terminator is missing or not properly connected; if you see a much higher value or open circuit, termination isn’t present or the wiring is broken. This 60-ohm figure reflects the effective impedance the network presents across the CAN pair, ensuring proper signal integrity.