Garmin GPS 24xd Receiver and Antenna Technical Reference for Garmin NMEA 2000 - Page 9

Backbone cable Length = 10 m Backbone cable Length = 6 m When the voltage-drop formula is applied to this example, the voltage drop is less than 1.67 Vdc. This NMEA 2000 network will function correctly when powered at the end: Resistance × Distance × Load × 0.1 = Voltage drop 0.053 × 22 (2 + 10 + 6 + 4) × 14 (4 + 5 + 5) × 0.1 = 1.63 Vdc End-Powered NMEA 2000 Network Designed Incorrectly Power cable Length = 2 m Drop cable Length = 2 m Drop cable Length = 4 m Drop cable Length = 6 m Backbone cable Length = 10 m Backbone cable Length = 6 m When the voltage-drop formula is applied to this example, the voltage drop is greater than 1.67 Vdc. This NMEA 2000 network will not function correctly when powered at the end. to function correctly, this NMEA 2000 network must be redesigned with the power connected to the center of the network. Resistance × Distance × Load × 0.1 = Voltage drop 0.053 × 24 (2 + 10 + 6 + 6) × 16 (4 + 5 + 7) × 0.1 = 2.04 Vdc 9