KB1017: LocoNet Accessory Power Requirements

This article was last updated on Jan. 25, 2016, 1:45 p.m.

This document outlines the power requirements for Digitrax LocoNet accessories.  To simplify wiring, Digitrax recommends providing individual power supplies for like accessories.  For example a power supply or power buss which only powers the PM42s.  A power supply or power buss used solely to power multiple DS64s.  UR9x and UP5 panels can be daisy chained provided adequate current is provided to properly power all the panels.  Through the use of individual power supplies, the chance of Ground Loops or sneak paths back to ground is minimized.  Using individual power supplies will also make troubleshooting much easier.  Many Digitrax LocoNet accessories allow the use of dc or ac power as an input.  Either is acceptable and there is no advantage of one over the other.  With that being said, it is imperative that the proper supply be used.  Check your accessory’s documentation for specific power requirements.  The latest documentation is always available for download from www.digitrax.com as a free download.

UR92

The UR92 includes a PS14.  The UR-92 draws up to 90mA.  It must be powered with a DC power supply.  Do not rely on LocoNet to power the UR92.  If using a generic power supply, it must provide 12-15vdc and a minimum of 90mA.  A December 2015 change to the UR92 circuitry requires 14vdc.  If the UR92 firmware doesn't sense 14vdc, the UR92 will not operate.

UR91

The UR91 draws up to 90mA.  It must be powered with a DC power supply.  Do not rely on LocoNet to power the UR91.  The PS14 is ideal for powering the UR91.  If using a generic power supply, it must provide between 12-15vdc and a minimum of 90mA.

UR90

The UR90 draws up to 90mA.  It must be powered with a DC power supply.  Do not rely on LocoNet to power the UR90.  The PS14 is ideal for powering the UR90.  If using a generic power supply, it must provide between 12-15vdc and a minimum of 90mA.

UP5

The UP5 draws up to 30mA.  It must be powered with a DC power supply.  Do not rely on LocoNet to power the UP5.  The PS14 is ideal for powering the UP5.  If using a generic power supply, it must provide between 12-15vdc.

To power multiple panels, plug the PS14 connector into the side 2.1mm power jack on one panel, then add a 22awg wire from the + common pad located between the two rear LocoNet jacks to the next panel + common pad.  A PS14 has an output of 300mA allowing multiple UR9x and UP5 panels from one PS14.  Do not exceed more current draw than the PS14 can supply.  For example, if powering a UR92 (90mA.), up to 7 additional UP5 panels (210mA.) can also be powered from the same PS14.  This combination of UR92 and UP5s, will draw the maximum current available from the PS14.

If using a generic power supply, its output must be between12-15vdc.  When considering the current output of the power supply, allow 90mA for each UR9x and 30mA per UP5 panel.  Add the current draw of each device.  The sum will be total current draw.  The power supply should be able to provide that much current.  For example, a power supply with a current output of 600mA can power 20 UP5 panels.

An easy way to add the 22awg wire to the UP5 is to solder a 6” pigtail to the UP5 and then connect the pigtail to a separate wire, which runs from panel to panel.  The wire can be run along with the Loco Net cable.  Another tip, solder the pigtail to the + common solder pad at the workbench before installation in the layout fascia.  Use a low wattage soldering iron with a fine tip and .015” - .022” solder.  Care must be taken when soldering to not damage any surrounding components.

BDL168

The BDL168 must be supplied with 12-16volts.  Either ac or dc power can be used to power the BDL168.  One BDL168 requires 100mA.  When powering more than one BDL168 make sure polarity is matched from BDL168 to the next.  The power supply output used to power BDL168(s) can be shared only with SE8c(s) on the layout.

SE8c

The SE8c must be supplied with 12-15volts.  Either ac or dc power can be used to power the SE8c.  Allow 100mA. per SE8c.  The power supply can be shared only with BDL168(s).

PM42

The PM42 must be powered with 12-18volts. Either ac or dc power can be used to power the PM42.  The PM42 requires 125mA per unit.  Do not share a power supply used for a PM42 with other LocoNet accessories.

PR3Xtra

The PR3Xtra includes a PS14.  If using a generic power supply, do not exceed 16vdc.  Damage can result to a decoder if more than 16vdc is applied when programming.

PR4

The PR4 includes a PS14.  If using a generic power supply, do not exceed 16vdc.  Damage can result to a decoder if more than 16vdc is applied when programming.

LNRPXtra

The LNRPXtra includes a PS14.  The LNRPXtra requires 250mA to operate properly.  If using a generic power supply, it should output between 14-18vdc with a current output of at least 250mA.

DS64

There are three different ways to power the DS64.  Track power (Trk A and Trk B), Auxiliary power (AX1(-) and AX2(+)) and power through the rear modular power connector.  The PS14 power supply can be used with Auxiliary or the rear modular power connector.  The DS64 requires 300mA for proper operation.  Only one DS64 can be powered per PS14.  A generic DC power supply between 12-14vdc and 300mA can be connected to a DS64 using the AX1(-) and AX2(+) power inputs on the Power and Track Connections screw terminal.  Power can be daisy chained to additional DS64s as long the polarity matching of AX1(-) and AX2(+) is maintained.  A generic AC or DC power supply between 12-14 volts and 300mA can also be plugged into the rear modular power jack.  The power supply used must provide enough current if it is powering more than one DS64.  For example two DS64s will require 600mA.

Some additional information for the DS64.  If using Trk A and Trk B to power the DS64, no LocoNet connection is necessary.  Switch commands will be sent through the rails to the DS64.  If using Auxiliary power or the rear modular power connector, a LocoNet connection must be made for the DS64 to receive switch command. Some layout owners use a separate Booster to power only the DS64s.

LNWI

The LNWI includes the PS14.  The LNWI requires 250ma to operate properly.


Track Powered Accessories

DS64

The DS64 allows for Track power as a means of powering it.  Connect the Trk A and Trk B screw terminals of the Power and Track Connections to the corresponding Rail A and Rail B track connections.

DS52

The DS52 uses position 4 for Rail A and position 5 for Rail B of the 5 Screw Terminal Connector.

DS44

The Red and Black wires from non-harness end of the decoder are connected to Track Power.

DS51K1

The Red and Black wires are connected to Track Power.

AR1

The AR1 input connections should be connect Rail A to position 5 and Rail B to position 4 of the 5 Screw Terminal Connector.

BXP88

The BXP88 uses the RA & RB terminals from the Booster for power.  An Optional 9v 150mA. power supply can be plugged into the rear 2.1mm barrel connector to keep the BXP88 powered on when track power is lost.  This auxiliary power supply can only be shared with other BXP88s.

BXPA1

The BXPA1 uses the INA & INB from the Booster for power.

NOTE: Attention to Polarity should be observed when connecting multiple Track Powered Accessories.


Starter Set Power Requirements

DCS100

The DCS100 is a Command Station/ 5A Booster.  This product has been retired.

DCS200

The DCS200 is a Command Station/ 8A Booster.  This product has been retired.

DB150

The DB150 is a Command Station/ 5A Booster.  This product has been retired.

DB200

The DB200 is an 8A Booster only.  This product has been retired.

DCS240

The DCS240 is a Command Station/ 5 or 8A Booster depending on the power input used.  The DCS240 requires a DC input only.

DCS210

The DCS210 is a Command Station/ 5 or 8A Booster.  It is only available in the Evolution Starter set.  The DCS210 requires a DC input only.

DB210

The DB210 is a 3, 5 or 8A Booster only depending on the power input used.  The DB210 requires a DC input only.

DB220

The DB220 is a Dual Output 3, 5 or 8A Booster only depending on the power input used.  The DB220 requires a DC input only.


Digitrax Power Supplies

PS2012e

The PS2012 provides the following dc voltage and current outputs depending on the Output Voltage Selector switch.

       G setting provides 23V @ 12amps
       HO setting provides 18V @ 15amps
       N setting provides 13.8v @ 20amps

There are two sets of Output Connections.  These outputs are electrically the same.  The outputs need to be properly fused.  The “Y” cable included with the PS2012 has self-resetting 5amp current limiters.  If the PS2012 is used with the DCS200 or DB200 an 8amp fuse, circuit breaker or current limiter must be used.  If “Y” cable is used with the DCS200 or DB200 only 5 amps of power will be available, defeating the purpose of using an 8 amp. Booster.

PS514

The PS514 is a 70watt Universal AC Power Supply.  This power supply offers many different voltage outputs.  Set the voltage selector as follows:

      G/O Scale – 20v        HO Scale – 15v       N Scale – 12v

Use the Blue electrical tip with the pigtail that is included with the Super Chief Xtra and Super Empire Builder Xtra Starter sets.  This power supply has been retired.

PS615

The PS615 is a 15 volt DC, 6A power supply.  It is included in the Evolution Starter set and is also sold separately.  It is for use with all current Command stations operating at 5 amps.

PS314

The PS314 is included with the Zephyr Xtra Starter set.  It provides 13.8vdc @ 3.6amps.  This power supply is not available separately.

PS14

Digitrax recommends the PS14 for powering all LocoNet accessories.  The PS14 provides 14VDC @ 300mA.


Digitrax Terms defined

Booster: Receives the DCC signal from the Command Station, amplify it & put it on the track as the power that runs the locos. You can have several boosters on a system, each driving its own track section. You can have both regular or auto reversing boosters depending on your needs. Also called Power Booster, Power Station.

Command Station: Each system has one Command Station that generates the DCC packets that tell the decoders what to do & produces Rail Sync so that all the devices you attach to LocoNet work together. With the Digitrax System you have a choice of several command stations to allow you to tailor your system to meet your needs. In an effort to keep the price down, in some Command Stations we have chosen to combine command station functionality with other system hardware components.

LocoNet: Digitrax's method of communication between LocoNet compatible devices on a model railroad layout. LocoNet Compatible devices are designed to work together on the network, and in some cases can also accept DCC commands from the track, but often go beyond the scope of simple DCC train control. \nLocoNet is a peer-to-peer Ethernet type multiple access network. Because of its design architecture, it is very robust and powerful. Layout implementation is simple and wiring is free form with minimal limits.

Polarity: The two directions of current flow, plus (+) and minus (-), in any electrical circuit. Mismatches in track polarity create reversing problems.

Power Supply A transformer that provides power to the DCC system. The transformer is not usually included with the DCC system.

Programming is the action of entering data into DCC decoders.