dealer certification section 2: building the network physical planning & documentation power...

Dealer CertificationDealer Certification

Section 2: Building the NetworkSection 2: Building the Network

Physical Planning & DocumentationPhysical Planning & Documentation

Power Sources & DistributionPower Sources & Distribution

Voltage Drop CalculationsVoltage Drop CalculationsCopyright © 2011 NMEA

Physical Planning & Documentation:Physical Planning & Documentation:Power Application ExamplePower Application Example

Determine Device Locations on the vessel

Determine Backbone Path through the vessel– Passes within 6 m of Each Device– Less than 100 m End to End (250 m w/heavy cable)– Backbone Must Not Branch

Determine Power Source and Application Point(s)

Physical Planning & Documentation:Physical Planning & Documentation:Planning the Physical LayoutPlanning the Physical Layout

Select Cable Type – Either Light (Most Common) , Mid or Heavy– Ensure Total Power Does Not Exceed Cable Rating

Determine Power Source and Application Point(s)(Power Tees)

More than one power application point IS allowed and MAY be needed as network size increases.

Physical Planning & Documentation:Physical Planning & Documentation:Planning the Physical LayoutPlanning the Physical Layout

Physical Planning & Documentation:Physical Planning & Documentation:Start With a Backbone DiagramStart With a Backbone Diagram

1. The length of each network segment and drop cable; location of tees and terminations

2. The identity and network LEN of each equipment on the network

3. The planned location(s) where power will be supplied to the network

4. The single location where the shield/drain wire will be connected to vessel’s non-current carrying RF ground.

Physical Planning & Documentation:Physical Planning & Documentation:Start With a Backbone DiagramStart With a Backbone Diagram

A completed network diagram contains all information necessary to complete the voltage drop calculations

Defines all cables, connectors, & devices needed for the complete installation

Physical Planning & Documentation:Physical Planning & Documentation:Load Equivalency Numbers (LEN)Load Equivalency Numbers (LEN)

Representation of the amount of current a device

uses from the bus All devices have a LEN equivalency number (LEN) The device manufacturer publishes this number

Physical Planning & Documentation:Physical Planning & Documentation:Load Equivalency Numbers (LEN)Load Equivalency Numbers (LEN)

1 LEN = 50mA , 20 LEN = 1 Amp Maximum LEN a single device can power from bus = 20 LEN is used to determine the voltage drop The higher the LEN, the higher the voltage drop

POWER INSERTIOIN POINT

Physical Planning & Documentation:Physical Planning & Documentation:Less Than 5 DevicesLess Than 5 Devices

NMEA 2000® Backbone Provides Power to Devices Network Devices Require 9 to 16 VDC Most NMEA 2000 devices get power from the bus

Physical Planning & Documentation:Physical Planning & Documentation:5 Or More Devices5 Or More Devices

2 meters

0.3 meters 0.3 meters

2 meters

2 meters

POWER

2 meters 6 meters 0.3 meters 0.3 meters 5 meters

Power Distribution:Power Distribution:Backbone Electrical ConnectionsBackbone Electrical Connections

Power Source Options– Ships Battery Connection (12.5 VDC)– Isolated DC to DC Power Supply (13.8 VDC)– Isolated AC to DC Supply (13.8 VDC)– Multiple Power Supplies (13.8 VDC must be consistent)

Backbone Shield Connection– Only Connected at a Single Point (Single Power Tee)– Connected to the non-current carrying RF Ground

Power Distribution:Power Distribution:Power Source ConsiderationsPower Source Considerations

Voltage Drop on Backbone Limited by – Voltage Available (Including Distribution Losses)– Voltage Required– Operational Common Mode Voltage Range : ± 2.5 VDC

Power Source Dependability– Minimum Battery Voltage = 11 VDC– Maximum Power Supply LEN Variation = 5%

Power Distribution:Power Distribution:Multiple Power SourcesMultiple Power Sources

Split Power– Compute Voltage Drop as for a Middle-powered

Backbone

Isolated Power Supplies– Each Power Supply Drives Backbone Segment;

Compute Voltage Drop for Each Supply as End or Mid-powered

Power Distribution:Power Distribution:End-Powered Backbone ExampleEnd-Powered Backbone Example

POWER 2 meters 5 meters6 meters

0.3 meters2 meters

3 meters

Power is traveling right only

Power Distribution:Power Distribution:End Power- Single Battery ExampleEnd Power- Single Battery Example

NET-LNET-HNET-SNET-C

Shield / Drain

Power Distribution:Power Distribution:Middle-Powered Backbone ExampleMiddle-Powered Backbone Example

2 meters

0.3 meters 0.3 meters

2 meters

2 meters

POWER

2 meters 6 meters 0.3 meters 0.3 meters 5 meters

Power is traveling left & right

Power Distribution:Power Distribution:Isolated DC Power Supply ExampleIsolated DC Power Supply Example


Shield / Drain

Power Distribution:Power Distribution:AC Power Supply ExampleAC Power Supply Example


Shield / Drain

Power Distribution:Power Distribution:Network Node Example (In Device)Network Node Example (In Device)

Isolation between Transceiver and CAN Controller Transceiver is Powered from Network Power

CAN CONTROLLER TRANCEIVER

I/O

Power Distribution:Power Distribution:Dedicated Power Cable RoutingDedicated Power Cable Routing

Drop Cable without power wires(provided by manufacturer)

Devices powered from backbone

– NMEA 2000 Transceiver circuit is powered by the backbone– Main power for LCD screen etc. is not powered by the backbone

Dedicated power (separate from backbone)

Device is more than 20 LEN

Data & power for NMEA 2000Transceiver ONLY

Multiple power T’s are needed when voltage Multiple power T’s are needed when voltage drop calculations exceed limits.drop calculations exceed limits.

Additional Power TeeOnly connected to the RightPower

Power Distribution:Power Distribution:Larger NetworksLarger Networks

Power Distribution:Power Distribution:Multiple Power SuppliesMultiple Power Supplies

– Shield/drain wires (grey) are all tied together and only bonded to RF grounding at one power insertion point

Heavy cable backboneHeavy Tees with Light / Mid drop connectionAllows for drop cable to connect into all devices

Power Distribution:Power Distribution:Larger NetworksLarger Networks

Light cable drop connection

Voltage Drop Calculations:Voltage Drop Calculations:Battery & Power Supply Battery & Power Supply

Battery Powered Distribution Loss Budget

Minimum Battery Voltage 11.00 VDC

3% Loss at Insertion - 0.33 VDC

Backbone Distribution Loss - 1.17 VDC

Minimum Voltage at Device 9.50 VDC

Power Supply Powered Distribution Loss Budget

Nominal Power Supply Voltage 13.80 VDC

5% Output Variation - 0.75 VDC



Voltage Drop Calculations:Voltage Drop Calculations:Why Do We Need Them?Why Do We Need Them?

Needed to ensure that all devices on the network are getting adequate power.

Devices furthest from the power insertion point will get less voltage than the closest device.

More than one power insertion point (Power Tee(s)) may be needed to feed all devices.

Voltage drop calculations help us determine this.

Voltage Drop Calculations:Voltage Drop Calculations:Calculating the Voltage DropCalculating the Voltage Drop

VOLTAGE DROP CALCULATION is Ohms Law; E= I x R E = Voltage Drop (VD)I = Total Network LEN (NL)R = Backbone Length (BL) in Meters (one way)

VD=.1 x NL x BL x Cable Resistance

– Cable Resistance Is in Ohms (Ω) per Meter– Light Cable = .057 Ω– Mid Cable = .015 Ω– Heavy Cable = .012 Ω

Voltage Drop Calculations:Voltage Drop Calculations:ExampleExample

Network LEN

Network Backbone Length

Cable Resistance-Light

Voltage Drop Estimate

13

14.3

.057 per meter

1.06 volts

E= I x R ( Ohms Law)E = voltage drop (VD)I = total network LEN (NL)R = backbone length in meters (one way) (BL)

VD=.1 x NL x BL x .0571.06= .1 x 13 x 14.3 x .057

Voltage Drop Calculations:Voltage Drop Calculations:Calculator Keystrokes- EXAMPLECalculator Keystrokes- EXAMPLE

NL (LEN) = 7 BL (Length) = 5.0 Cable Type= Light (.057 Ω / m)

Calculator Keystrokes are…

.1 x 7 x 5 x .057 = 0.1995 Round up at second decimal place → .20


NL (LEN)=3 BL (Length) = 4.2 Cable Type= Light (.057 Ω / m)


.1 x 3 x 4.2 x .057 = 0.07182 Round up at second decimal place → 0.07


NL (LEN)=12 BL (Length) = 9.8 Cable Type= Light (.057 Ω / m)




NL (LEN) =15 BL (Length) = 20.3 Cable Type= Heavy (.012 Ω /m) Calculator Keystrokes are…



NL (LEN)=19 BL (Length) = 28 Cable Type= Mid (.015 Ω / m) Calculator Keystrokes are…

.1 x 19 x 28 x .015 = 0.798 Round up at second decimal place → 0.79

Voltage Drop Calculations:Voltage Drop Calculations:When Do We Calculate Segments?When Do We Calculate Segments?

When VD exceeds 1.17 VDC using a ship battery powered network

When VD exceeds 3.55 VDC using a regulated 13.8 VDC power supply

Battery Powered Distribution Loss Budget

Minimum Battery Voltage 11.00 VDC

3% Loss at Insertion - 0.33 VDC



Power Supply Powered Distribution Loss Budget

Nominal Power Supply Voltage 13.80 VDC

5% Output Variation - 0.75 VDC



Enter devices starting at the device closest to the power insertion point.

Enter segment lengths starting with the segment between the power insertion point and the first device.

Always use the last drop length as part of the total backbone length calculation

Compute currents. Compute voltage drop in each segment for each

device. Add the voltage drops in the column.

Voltage Drop Calculations:Voltage Drop Calculations:Calculating the SegmentsCalculating the Segments

Voltage Drop Calculations:Voltage Drop Calculations:Segments on the NetworkSegments on the Network

Calculate segments left of power

Calculate segments right of power

Voltage Drop Calculations:Voltage Drop Calculations:Left Side of Power TeeLeft Side of Power Tee

Voltage Drop Calculations:Voltage Drop Calculations:Right Side of Power TeeRight Side of Power Tee

NEXT: Section 3NEXT: Section 3

Connecting to Other Data Sources and NetworksConnecting to Other Data Sources and Networks

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Advanced Setup, Certification, TroubleshootingAdvanced Setup, Certification, Troubleshooting

Copyright © 2011 NMEA

dealer certification section 2: building the network physical planning & documentation power...

Documents

meters power

power distribution

total power

dc power supply

power application point

power application example

network len

vdc multiple power supplies