Power Management Products

I have a 4x8 H0 scale layout.  I'm 13 years old and REALLY thinking about switching to DCC, I need to know really fast because I want to ask my parents to get it for Christmas.You wouldn't know by looking at those who edit the Tech Support Depot, but there actually was a time when we too were thirteen, and just starting out in model railroading.  In many ways, we still are thirteen years old; we just can't move as fast.  Consider this photograph from our youth: This little bit of ancient model railroad history dates back to the 1950's, ...

Q: If my layout is experiencing short because of a thrown switch, how can you reset the switch using DCC? Many Digitrax operators use the PM42 Power Manager, which provides protection to four power sub-districts. One segment of the PM42 is used to control track switch power, with the balance being used for train power. When the inevitable happens and a train runs into a thrown switch, resulting in a short, the PM42 shuts down the track power in that segment, while the track switch power is maintained, allowing you to throw the offending switch. Because the PM42 isolates only ...

My question is: How do I mount the PM42? Do I need a special housing in order to mount it under table? It appears to me that mounting it flush against a surface would prevent, or make it extremely difficult, to attach the 44-pin connector. Digitrax manufactures three devices which have a 44-pin connector. These are the BDL168 (and its predecessor the BDL16), the SE8C and the PM42 (and its predecessor, the PM4). These best approach to mounting these devices is to screw the connector directly to the wiring panel board. Drill mounting holes in the end of the 44-pin ...

The tuneable trip current (TTC) adjustment allows you to set the current at which the reversing section reverses when the train crosses the gap into the section. This allows you to improve the operation of your reversing sections.The tuneable trip current is adjustable from .25 amps to 8 amps. Turning the TTC screw clockwise increases the current trip point and turning the TTC screw counterclockwise decreases the current trip point. The total adjustment is approximately one half revolution of the TTC adjustment screw. The TTC adjustment is made using a full load on the reversing track--the total number of locomotives/cars ...

The AR1 is usually located close to the point where the gaps are cut for the reversing loop. The length of the reversing loop is determined by the maximum length of the train that will use the loop.1. Turn off track power. (Note: Failure to turn off power before connecting your AR1 may damage your AR1.)2. Connect Track Power from Rail A and Rail B mainline to the AR1. Rail A connects to terminal 5 and Rail B connects to terminal 4.3. Connect the wires from the reversing section to terminals 1 & 2 on the AR1. (Note: terminal 3 ...

Power Management is a concern on every layout.  With Digital Command Control, the main concern is that enough power is supplied to evey track section on the layout so that the digital signal is transmitted to the decoders in the locomotives and turnouts.Each locomotive uses power from the track, some for the motor, some for headlights and other functions and some for the command control electronics in each locomotive.  More electrical power is necessary to run more locomotives on the layout.  Digitrax boosters provide between 2.5 amps & 8.0 amps.  A small N Scale or HO Scale layout with two to ...

When using the your PM42 with an AR1 Auto Reversing controller do not use the "fastest setting" in the Short Circuit Sensitivity Settings section:

44 pin connectors with screw terminals were originally designed by a company called LWH3.  Their products allow you to install the PM42, BDL168, and SE8C without having to solder to the 44 pin connector.  The product line was sold to Accu-Lites.  These products are available online directly from Accu-Lites at www.acculites.com              

  One major consideration is that the reverse section controlled by the AR1 must be longer than the longest train. It is a common misconception that the AR1 will work with an analog controlled ("DC") locomotive; it will not. The AR1 is meant to be used only in a DCC enviroment. The AR1 coordinates the phasing of the reversing section with that of the mainline (non-reversing) section of the layout.  Because a Digitrax layout can be a complex enviroment with detection and transponding, etc. consult the approriate Digitrax user manuals and the Digitrax Tech Support Depot knowledge base.  

We have designed a layout at my place with double main line with reverse loop at each end. Plus there is a branch line with two reverse loops that in one loop is connected to the main line. The main lines stay double track even at the split. The branch stays single with only one connection with the main. My plans where to use the AR1 for all my reverse loops and the PM42 for my power control. What if any problems do you see with all these loops? Nothing, if you can guarantee that at any given time only ...

How do you wire an AR1 with a BD4 so that you get block detection within the reverse loop and without the BD4 permanently detecting the AR1? It should be wired with the AR1 between the power source and the BD4. All four detection sections of the BD4 will have to be inside the reverse loop.

What is the difference between boosters and power management? A Booster is the device that provides the electrical power to the railroad. Most Digitrax command stations have a combined booster. The command station generates the DCC signal then sends it through a booster to the layout. A small model railroad may only have the command station and booster, while a large railroad will have numerous boosters. Multiple boosters provide more power to larger layouts.Additional boosters receive the DCC signal from the command station via LocoNet. Power management usually refers to the devices which act as circuit breakers and power distributors. ...

Q: I want to use the AR1 for a reverse loop between two different power districts (i.e. different booster for each connected track). Is this possible or do I need to make a special wiring set-up to do this? SThis diagram shows how to do this The usual rules apply, the AR1 track section must be longer than the longest train you will run.

The BDL168 is designed to be used with power management devices such as PM42. The BDL168 is designed to operate “downstream” of the Digitrax boosters and power management devices. The BDL168 is the "last" device in the chain from booster to power manager to BDL168. It is connected directly to the track detection section. There should be no other connections to any detection section that will draw track power or the detection section will always show occupied. If a device is used to switch off power feeding the BDL168 and the track it is connected to, for example, a PM42 ...

How can I remotely monitor the input and output status of a section of the PM42 that is configured to act as a circuit breaker at a remote location? The final output stage, of each section, of the PM4 or PM42 is a DPDT relay. The contacts of this relay act in a similar fashion as the contacts of a DPDT toggle switch. These inputs and outputs can be monitored in a variety of ways. Three common monitoring devices are a LED (with appropriate resistor), a lamp (of the appropriate voltage), or an optical coupler (with appropriate resistor). The following ...

I'm helping a friend rewire an existing layout from analog to digital. You might be familiar with the layout, it is the original Clinchfield layout that Model Railroader built back in the late seventies, believe it or not. The layout, of course, is blocked for analog through DPDT switches which have been eliminated. I was able to repair the wiring back to original using the drawings that MR printed. The layout uses common rail wiring, this is what I have to work with, and to rewire using home run wiring would be a MAJOR rework, not doable. I was able ...

Can I combine the power input requirements for PM42's with other units for economy?Digitrax recommends each PM42 module to have its own seperate power source. The criteria for choosing a power supply for the PM42 is any power source that can deliver 12-15V AC or 13.8-15V DC with a minimum of 125 ma. The Digitrax PS14 meets the minimum power requirement of a PM42.It is possible to power more than one PM42 from a single power source. When powering multiple PM42's special care must be taken to insure identically phasing of all PM42's and ample current availability to power all ...

If I use a non-Digitrax compatible system, what features of the PM42 Auto reverse/Short Circuit Managers (SCM) will I lose?The PM42 can be used as a stand alone Auto reversing unit and Short Circuit Manager with many other non-Digitrax systems, but for systems without LocoNet capability a number of networked management features will not be available.For example, the PM42 sends out real-time, event driven (non-polled) information to the LocoNet about fault problems and resolution, auto reverse actions and also identifies the affected sub-districts. This allows other devices, such as PCs, the Digitrax Signaling system, Digitrax Transponding or other detection and ...

The PM42 was specifically designed to work with Digitrax Direct Home wired layouts. Any system that is configured this way will work with the PM42 with no interoperability issues. For example, CVP uses interoperable booster connections.The PM42 can be used with a DC system if it is hooked up in the negative ground return path, or even a Marklin AC digital (trinary) booster. It is possible for the PM42 to be used with most DCC systems. Digitrax has no control or knowledge of each specific non-Digitrax system and how it may interact with the PM42.

My PM42s seem to correctly trip on track shorts and auto-reverse reliably, but the power briefly drops out during these events, and when the PM42s attempt a fault recovery into a persistent short circuit, why is this?No power on earth can stop the track voltage of the booster from collapsing to a low value when a true short circuit is present. This is simply Ohm’s law in action!Actual track voltage seen depends on: the loop resistance of the short circuit, the current capacity of the booster and power supply and whether the Booster employs "smart" fault detection and recovery along ...

My dealer told me that the when the PM42 changes polarity on a section of track, that it should remain that way till another "short" is detected. Mine will change polarity for about 1 - 1.5 seconds and then change back. Is this normal and my dealer told me wrong? Your dealer is correct. You may need to adjust the trip timing of that particular node of the PM42.

Q: How do I use the AR1 and automatically control the turnout? I'm confused here. It is good that the AR1 controls the switching of the track power for a reverse loop automatically but it seems the turn out direction also needs auto control. Am I missing something here? Need help understanding...Please explain. A: The AR1 is handles correcting the track polarity mismatch when a reversing section is encountered by a locomotive. When the polarity inside the reverse section does not match the polarity outside the reverse section, the AR1 detects the short circuit and flips the polarity so that ...

On Page 9 of the instructions (under 5.0 Op Sw Set Up) I am to connect my DT400 throttle to my powered PM42 . . . 1. Does “powered” mean having the PS-14 power supply to the PM42 connected and energized? Yes. We took another look at the documentation and it means that the PM42 should be operating with its own power supply. What you are doing is using the DT400 to program the internal controls of the PM42; to do so would require that the PM42 be in its operating state, thus the power supply. The DT400 is merely ...

The installation instructions indicate that a PS14 be used to power the PM42. Is it necessary that I cut the wire from the PS14 so that is can be attached it to the 44-pin connector, or is there a male adapter available for the connection? Yes, currently you will need to cut the wire, strip the ends and solder them to the edge connector of the PM42. Please see the related articles below. Which lead from the PS14 is to be soldered to terminal 3 on the 44-pin connector and which is to be soldered to terminal C? The PM42 ...

Since many Zephyr and Zephyr Xtra Starter Sets are used on smaller railroads, a natural choice for setting up an automatic reversing section would be an AR1. If you have more than one reverse loop, then the PM42 is a better choice. These automatic reversing strategies will work equally well for any Digitrax system using any Digitrax Starter Set.  Alternately for larger railroads, an auto reversing booster such as the DB150 can be used for automatic reversing if the section is large.

  Q:  Can I use a PM42 with a non-Digitrax DCC Command system? A:  The PM42 was specifically designed to work with Digitrax Direct Home wired layouts. Any system that is configured this way will probably work with the PM42 with no interoperability issues. Digitrax has no control over or knowledge of each specific non-Digitrax system and how it may interact with the PM42. The PM42 can be used as a stand-alone auto-reversing unit and short circuit manager with many third party DCC systems, but for systems without LocoNet capability a number of the networked management features will not be available. ...

Q:  What is the preferred way of protecting a reverse loop with circuit breaker management and still having automatic reversing? A:  There are two ways of protecting a reversing section with a circuit breaker and reversing section controller. 1.  Use one PM42 (circuit breaker manager) and one AR1 (automatic reversing section controller). 2.  Use two PM42s (one as a circuit breaker manager and one as a reverse section control). The following diagram displays both methods: a) The first method (left), is where one section of a PM42 configured for circuit breaker operation feeds one or more AR1s (automatic reversing section controller), or b) The second method ...

Q:  Can two sections of a single PM42 be configured to perform both the task of a circuit breaker and also automatic reverse section control for a single reverse loop? The PM42 can be configured so that one section of the PM42 is used for circuit breaker operation, feeding into another section of the same PM42 which is configured for automatic reverse section control. In the field, this configuration has been found to be unreliable in some layout configurations.  If you are having problems getting this to work in your setting, we recommend using an AR1 to handle the automatic reversing secion.  The ...

Q: What is the basic configuration and OpSw settings for a section of the PM42 when configured for circuit breaker control? A:  The PM42 is a 4 section multi-purpose device where each of the four sections can be individually configured to act as either a circuit breaker, or automatic reverse loop controller. The PM42 monitors the current flow to the rails and interrupts the connection when it senses that the current demands exceed the upper allowable current level determined by the User controllable Option Switch (OpSw) settings. The power flow of a layout's command control system starts with the command station, or ...

  Q:  What is the basic configuration and Option Switch (OpSw) settings for each of the four sections of the PM42 when configured for automatic reverse section control? A:  The PM42 is a 4 section multi-purpose device where each of the four sections can be individually configured to act as either a circuit breaker, or auto-reverse section controller or DPDT relay. When configured as an auto-reverse section controller, the PM42 adjusts the rail phasing of the reversing section it controls whenever a locomotive, or car with metal wheels, bridges the gaps between the rails of that reverse section and an adjacent non-reversing section ...

PM42 Short Circuit/Auto-Reversing Failure When used with Zephyr (DCS50) The PM42 is designed to control 4 independent power subdistricts that can be set up as either a “Short Circuit Manager” (the factory setting) or as an “Auto-Reversing Controller.” The PM42 factory setting for trip current is 3 amps. The trip current can be modified to settings from 1.5 amps – 12 amps to accommodate the needs of your system. In addition, each of the 4 power subdistricts can be set for slow, regular, faster or fastest short circuit management. While a trip current of 3 amps will work with most ...

Q:  How do I program the PM42 Option Switches (OpSw) with a DT400 throttle? A:  The PM42 OpSw settings are used to set up the PM42, adjusting the trip current, short circuit management (including sensitivity), and/or auto-reversing. Note: The factory default setting on all PM42 OpSws is “thrown” or “t”. Follow the steps outlined below to program the OpSw settings of the PM42 using the DT400 series throttle with any Digitrax command system. 1) Connect the PM42 to a DCS50, DCS51, DB150, DCS100, or DCS200 with a standard LocoNet cable. 2) Connect the PM42 to an external power source; Digitrax ...

  Q:  How do I program the PM42 Op Switches with a DT300 throttle? A:  The PM42 OpSw settings are used to set up the PM42, adjusting the trip current, short circuit management (including sensitivity), and/or auto-reversing. Note: The factory default setting on all PM42 OpSws is “thrown” or “t”. Follow the steps outlined below to program the OpSw settings of the PM42 using the DT300 throttle with any Digitrax command system. 1) Connect the PM42 to a DB150, DSC050, DSC100 or DSC200 with a standard LocoNet cable. 2) Connect the PM42 to an external power source; Digitrax recommends the ...

  How do I program the PM42 Op Switches with a DCS50 (Zephyr) throttle? The PM42 OpSw settings are used to set up the PM42, adjusting the trip current, short circuit management (including sensitivity), and/or auto-reversing. Note: The factory default setting on all PM42 OpSw's is “thrown” or “t”. Follow the steps outlined below to program the OpSw settings of the PM42 using the keypad of a Digitrax Zephyr. 1. Connect the PM42 to the Digitrax Zephyr with a standard LocoNet cable. 2. Connect the PM42 to an external power source; Digitrax recommends the PS14. Note: Before entering Switch Mode ...

  Digitrax AR1 is a DCC Automatic Reversing Controller.  We have become aware of another product of a similar name that may cause our customers some confusion. Circuitron makes an automatic reversing unit called the AR-1 that is used for automatic reversing of analog powered trains. The Digitrax AR1 is not the same device and does not work in the same way.

I was planning on purchasing the Digitrax Super Chief Radio 5 amps but several members in the club told me to buy them Super Chief Radio 8 amp for my HO Layout.  They said you will need the power when you start expanding.Question:Is it ok to use the 8 amp version for my HO layout?Answer:Yes it is fine to use 8 amp Digitrax boosters on your HO layout.  The choice between 8 amp and 5 amp command station/boosters, it is a question of how much power your railroad is likely to consume on your railroad as it is built today.  ...

The answer to this question applies to all Empire Builder sets including Super Empire Builder XtraQ:  I have just purchased a Super Empire Builder set. My expectations are for it to operate an N-Scale switching layout right now with future expansion to a larger N-Scale layout. I am a little confused as to which power supply I would need at this time. I am reading about power supplies and inline fuses, all of which is a little overwhelming to me as I am getting back into the hobby. Can you recommend which power supply will be better for me as ...

Use a throttle to change the PM42's Option Switches 01, 02 and 09 as detailed in the PM42 instruction manual. The PM42's trip current threshold can be set at a value from 1.5amps to 12 amps. Always use the lowest possible setting, consistent with good operation and reliable short circuit detection and recovery. Higher current settings are not "better." We ship the PM42 with a moderate current trip threshold of 3amps so it will work on most DCC boosters and layouts with no changes.This is because some boosters cannot supply enough current with the track feeder resistance to reliably allow ...