Murphy 78-70-0232, Руководство по установке

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Section 78 00-02-0629
08-08-07 - 9 -
Maximum Power Supply Voltage Drop
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
Ground the Network
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.
Checking Your Network
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