1. Dealer Certification Section 2: Building the Network Physical Planning & Documentation Power Sources & Distribution Voltage Drop Calculations Copyright © 2011 NMEA

2. Physical Planning & Documentation: Power Application Example

3.  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: Planning the Physical Layout

4.  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: Planning the Physical Layout

5. Physical Planning & Documentation: Start 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.

6. Physical Planning & Documentation: Start 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

7. Physical Planning & Documentation: 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

8. Physical Planning & Documentation: 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

9. POWER INSERTIOIN POINT Physical Planning & Documentation: Less 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

10. Physical Planning & Documentation: 5 Or More Devices 2 meters 0.3 meters 2 meters POWER 2 meters 6 meters0.3 meters 5 meters

11. Power Distribution: Backbone 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

12. Power Distribution: Power 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%

13. Power Distribution: Multiple 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

14. Power Distribution: End-Powered Backbone Example POWER 2 meters 5 meters6 meters 0.3 meters 2 meters 3 meters Power is traveling right only

15. Power Distribution: End Power- Single Battery Example NET-L NET-H NET-S NET-C Shield / Drain

16. Power Distribution: Middle-Powered Backbone Example 2 meters 0.3 meters 2 meters POWER 2 meters 6 meters0.3 meters 5 meters Power is traveling left & right

17. Power Distribution: Isolated DC Power Supply Example NET-L NET-H NET-S NET-C Shield / Drain

18. Power Distribution: AC Power Supply Example NET-L NET-H NET-S NET-C Shield / Drain

19. Power Distribution: Network Node Example (In Device)  Isolation between Transceiver and CAN Controller  Transceiver is Powered from Network Power CAN CONTROLLERTRANCEIVER I/O

20. Power Distribution: Dedicated 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 2000 Transceiver ONLY

21.  Multiple power T’s are needed when voltage drop calculations exceed limits. Additional Power Tee Only connected to the Right Power Power Distribution: Larger Networks

22. Power Distribution: Multiple Power Supplies –Shield/drain wires (grey) are all tied together and only bonded to RF grounding at one power insertion point

23.  Heavy cable backbone  Heavy Tees with Light / Mid drop connection  Allows for drop cable to connect into all devices Power Distribution: Larger Networks Light cable drop connection

24. Voltage Drop Calculations: Battery & Power Supply Battery Powered Distribution Loss Budget Minimum Battery Voltage11.00 VDC 3% Loss at Insertion- 0.33 VDC Backbone Distribution Loss- 1.17 VDC Minimum Voltage at Device9.50 VDC Power Supply Powered Distribution Loss Budget Nominal Power Supply Voltage13.80 VDC 5% Output Variation- 0.75 VDC Backbone Distribution Loss- 3.55 VDC Minimum Voltage at Device9.50 VDC

25. Voltage Drop Calculations: 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.

26. Voltage Drop Calculations: Calculating 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

27. Voltage Drop Calculations: Example 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.057 1.06=.1 x 13 x 14.3 x.057

28. Voltage Drop Calculations: Calculator 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

29. Voltage Drop Calculations: Calculator Keystrokes- EXAMPLE  NL (LEN)=3  BL (Length) = 4.2  Cable Type= Light (.057 Ω / m)  Calculator Keystrokes are… .1 x 3 x 4.2 x.057 = 0.07182  Round up at second decimal place → 0.07

30. Voltage Drop Calculations: Calculator Keystrokes- EXAMPLE  NL (LEN)=12  BL (Length) = 9.8  Cable Type= Light (.057 Ω / m)  Calculator Keystrokes are… .1 x 12 x 9.8 x.057 = 0.67032  Round up at second decimal place → 0.67

31. Voltage Drop Calculations: Calculator Keystrokes- EXAMPLE  NL (LEN) =15  BL (Length) = 20.3  Cable Type= Heavy (.012 Ω /m)  Calculator Keystrokes are… .1 x 15 x 20.3 x.012 = 0.3654  Round up at second decimal place → 0.37

32. Voltage Drop Calculations: Calculator Keystrokes- EXAMPLE  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

33. Voltage Drop Calculations: 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 Voltage11.00 VDC 3% Loss at Insertion- 0.33 VDC Backbone Distribution Loss- 1.17 VDC Minimum Voltage at Device9.50 VDC Power Supply Powered Distribution Loss Budget Nominal Power Supply Voltage13.80 VDC 5% Output Variation- 0.75 VDC Backbone Distribution Loss- 3.55 VDC Minimum Voltage at Device9.50 VDC

34.  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: Calculating the Segments

35. Voltage Drop Calculations: Segments on the Network Calculate segments left of power Calculate segments right of power

36. Voltage Drop Calculations: Left Side of Power Tee

38. Voltage Drop Calculations: Right Side of Power Tee

40. NEXT: Section 3 Connecting to Other Data Sources and Networks & Advanced Setup, Certification, Troubleshooting Copyright © 2011 NMEA