Murphy HelmView GPS Kit 사용자 설명서

 

9 - 

The NMEA 2000 network is designed to work properly as long as there is no more than a 1.5 
volt difference in the power supply voltage between any two devices on the network.  
Therefore, you should perform an estimate of the voltage drop across a network using the 
following equation: 

Voltage Drop = 0.1 x Network Loads x Network Length x Cable Resistance / 100 

Where: 

Network Loads is sum of Load Equivalent Numbers (LEN) for all 

 devices 

 

Network Length is in meters 

 

Cable resistance is in ohms/100 meters 

The NMEA 2000 network should be grounded at ONE location.  Grounding at more than one 
location may produce ground loops, which can cause problems with communications on the 
network.  In addition to the ground wire, connect the drain or SHEILD wire at the supply ground 
location and NO other place. 

Verify that the network has been correctly designed and installed by reviewing the following 
checklist: 

• Number 

of 

devices does not exceed 50 

•  Maximum Micro cable distance between any two devices does not exceed 100 meters 

(328 feet) 

•  No drop should be greater than 6 meters (20 feet) 

•  Termination resistors are installed on both ends of the trunk 

•  The network is grounded at a single location 

•  The SHIELD wire is connected to a single point, the supply ground