Digital Command Control

Digitrax DT100R Throttle Operating Instructions

 
Notice: The DT100 and DT100R Throttles have been discontinued by Digitrax since 2000, and parts are no longer available from Digitrax as of January 2006. DT100 and DT100R throttles sent to Digitrax for repair will be returned to the owner. Please refer to the section on "Maintenance" below for assistance in solving problems with the DT100 and DT100R throttles.

The Digitrax DT100R throttle is essentially a DT100 throttle that contains a simplex (one-way) transmitter that uses its cable (LocoNet) connection to establish initial locomotive address selection and other related functions. After a DT100R has selected a locomotive and/or established a MU consist, it may then be untethered and will automatically switch to radio operation for all subsequent speed, direction and function commands. In the tethered mode the DT100R behaves exactly as a regular DT100 with exactly the same features and capabilities.

The DT100R throttle uses a combination of color-coding, LED indicators, a LCD display and multi-function buttons to accomplish a wide range of capabilities in a compact and light-weight case that is easily held in the hand. The 6-wire flat cable with RJ12 plug extending out from the throttle is for connecting to LocoNet only. The antenna for the radio transmitter is entirely within the throttle case.
 

Control Panel Description

Color Codes
Color coding is used on the DT100R control panel to indicate how the keys are used. GREEN buttons and indicators handle locomotive speed and direction control. The RED button is , RUN/STOP. It is the only button that is red and is so color coded for emergencies. BLUE buttons handle function control. When the function mode is active the GREEN buttons on the bottom row take on the BLUE meanings F3/F7, F1/F5, F2/F6 and F4/F8, in left-to-right order.

Left and Right Throttle Knobs
The throttle knobs on the DT100R are encoders, not rheostats (variable resistors), and give very smooth, fine speed control. They can be turned continuously; there is no left and right stop points as with a variable resistor. In the 128 speed step mode it can take several turns of the knob to go from stop to full speed.

The tracking characteristics of the knobs can be customized for either "straight line" or "ballistic" tracking. With straight line tracking each movement of the knob causes a fixed rate of change in the display. With ballistic tracking, the faster you move the throttle knob, the faster the data changes in the throttle. Ballistic tracking is the default setting, but it can be changed as described under Setup. For wireless use, it is recommended you change to Straight Line tracking.

Direction Indicators
These are the LEDs located above and to the center of the case next to each throttle knob, with the symbol . They have the following meanings:

Program Mode Indicator (PROG)
Located to the lower left of the right throttle knob. This LED indicates this DT100R throttle is in the programming mode. In this mode the throttle knobs do not control any selected locomotives, but permit the use of the Service Mode programmer in the Command Station or perform Operations Mode programming on the mainline. See section on Programming.

Address Mode Indicator (EXP)
This LED indicates whether the active throttle knob is controlling a 2-digit short address, a 4-digit aliased address or a 4-digit long address, as follows:

Note: The North Raleigh Model Railroad Club strongly recommends against use of alias addresses, especially at Train Shows. Further information on alias addressing is excluded from these descriptions.

Any two of 2-digit, 4-digit and/or alias addresses can be mixed on the same throttle.

The LCD Display
The DT100R display is a single line LCD display used to display several different types of information.

The three small mode indications across the top of the LCD define the current operational state of the DT100R, and indicate whether you are in MU (multiple unit or consist mode), LOCO (regular locomotive operations mode) or SWITCH (turnout control mode) mode. Only one of the indicators will be lit at any time. The DT100R defaults to the LOCO mode and returns to this mode if you change to another operational mode and don't do anything within about 6 seconds. Use the button to toggle among these operational modes.

The numbers and letters in the LCD display have different meanings depending on the current DT100R mode and the functions being executed, and they may be flashing or not. A flashing display is usually a prompt. All displays and meanings are described on this web page.

The colon : in the middle of the display is flashing when the Fast Clock is being displayed. There is no colon : displayed when working with 4-digit addresses and a steady colon : will be displayed when working with 2-digit addresses and when status editing.

DT100R Throttle Control Buttons

DT100R Throttle Configuration Options

The DT100R throttle has an individual throttle OPTION mode that is used to customize the throttle. The options are assigned as hexadecimal numbers representing combinations of options as shown in the following tables. The default values, shown in bold are generally satisfactory for most operations, however it is recommended for radio operations that ballistic tracking be turned off by setting the Primary Option value to 00.

It is strongly recommended that all locomotives assigned to the throttle (both throttle knobs) be released (i.e. dispatched) before any options are changed.

Changing DT100R Configuration Options
To change DT100R configuration options be sure the throttle has a good battery installed and then proceed as follows:

 
DT100R Major System Modes and System Startup

DT100R Fast Clock

DT100 family throttles in conjunction with the DCS100 and DCS200 Command Stations offer a networked fast clock on the all the DT100's in the LocoNet system. The fast clock display is a 4-digit 24-hour format clock with the colon : blinking. The DT100R can be set so its default display is either the fast clock or the LOCO mode display — when there is no activity on the DT100R for about 6 seconds, the display reverts to the default display set up in the DT100R. Turning a knob or pressing any button will cause the display to change to reflect the current throttle activity. LOCO mode is the default display for the DT100R — see Changing DT100R Configuration Options above in this section for changing this default display to the fast clock.

When a DT100R is plugged into LocoNet the system will update its fast clock time and rate so it is synchronized to the rest of the system.

Each DT100R throttle can be set up with its own alarm. When the fast clock time matches the private alarm time set the DT100R will beep and flash up the message ALAr to indicate the alarm time has elapsed. The alarm time uses the 24-hour time format.

The fast clock rate is user selectable from 1:1 to 100:1 in steps of 1. Setting the clock rate to 00 will stop the fast clock in the whole system at the currently displayed time. To re-start, set the clock rate to a non-zero value.

The fast clock functions are set and modified as follows:

Locking the DT100R Throttle

Pressing the and buttons simultaneously will lock the throttle, with the display as Locd. Pressing both buttons again will toggle out of the locked mode and return the throttle to normal. In Locked mode, all of the buttons are rendered inactive.

Radio (Tetherless) Operation with the DT100R Throttle

The DT100R throttle will operate as a standard DT100 throttle when it is plugged into LocoNet, and as a radio wireless throttle when unplugged from LocoNet and at least one UR91 radio receiver is present. When the DT100R is plugged into a working LocoNet, it will verify that at least one radio capable receiver is present. The DT100R will then assume the current Network ID that the radio receiver(s) are set to, and subsequently allow itself to switch to radio operation when it detects a disconnect from LocoNet.

LocoNet Connection
On connection to a LocoNet that has radio capability, the DT100R LCD display will flash the radio status code rA:0n where the number "n" signifies the LocoNet ID being used by all receivers on the system it is connected to. The display will then switch to normal DT100R tethered operation displays and actions. If the system does not have a UR91 or equivalent device, the DT100R will not display the rA:-- message to show that it cannot operate in radio mode on that system.

Display Power Down
When a DT100R throttle is connected to a LocoNet and received the LocoNet ID number it will allow tetherless operation of locomotives that have been selected into either throttle knob. If an untethered DT100R detects no user throttle activity for about 3 minutes, it will enter Power Saver mode and display r- PS on the display until a throttle or button action restores normal activity and displays. If the DT100R has a locomotive assigned to it and is in Power Saver Mode, it will continue to "check in" with the system every 60 seconds telling the system "I'm still here". This keeps the system from releasing that locomotive back to "common". The direction LED's of active throttles may blink every 1.5 seconds when the DT100R is checking to see if any new key or encoder input has been made. The easiest and fastest way to signal the DT100R to exit from power saver mode is to hold down either the or button.

To force a DT100R to enter the lowest power use idLE state, either connect it to a LocoNet which is in sleep mode, or simultaneously press the and buttons to reset the throttle. Once the DT100R has been reset it remains idLE until it is reconnected to an active LocoNet. You may also simply remove the battery to completely power down an untethered DT100R.

Releasing a Locomotive
When working in the radio mode, pressing the button will immediately release the controlled locomotive as common to the system and the throttle will become inactive. To re-select this locomotive, the throttle must be reconnected to LocoNet. The DT100R will automatically reselect that locomotive when plugged in to LocoNet. Due to the close proximity of the button to the right throttle knob reverse button, you may wish to assign locomotives to the left throttle knob for normal operation.

Multiple Unit Operations
The DT100R must be connected to LocoNet to either make up or break down consists. Consists may be operated normally with the DT100R tetherless.

Programming
The DT100R must be connected to LocoNet to use its Service Mode programming. When tetherless, Operations Mode programming will work normally except that the DT100R will not receive any return or feedback messages.

Switch Mode
Switch Mode works to throw switches and routes normally when the DT100R is tetherless. However, Route Editing requires a connection to LocoNet.

Ballistic Tracking
When operating in the radio mode, throttle knob tracking will feel slightly different than when connected to LocoNet. When in the radio mode, slow movement of the throttle knob will result in improved locomotive response.

Throttle Orientation for Normal Operation
The orientation to hold the DT100R in normal usage is from horizontal to 30° upward in a natural hand position about 12" out from your body. This gives the best radio coverage. Note that occasionally wiring, metal plumbing, HVAC ducting and other items may cause small areas of poor reception around the layout. Moving about 6" - 24" in any direction or varying the orientation of the DT100R will typically overcome any dropouts.

Fast Clock (Chief only)
When the Fast Clock option is being used, the DT100R keeps track of and displays Fast Time based on what the Fast Time was the last time the DT100R was connected to LocoNet. If Fast Time changes (someone edits it) while tetherless, the DT100R will see the change only when it is plugged into LocoNet at which time its display will be updated.

Battery "Fuel Gauge"
The DT100R continually checks the voltage of its battery while running tetherless. If it detects a low voltage it will beep twice within a second and display bt:nn on the display. The n is the number of times the warning has sounded. The warning will continue every 5 minutes until the battery is changed. Don't panic when this warning appears, as the throttle unit will continue to operate normally for an extended time. A prudent action would be to change the battery as soon as reasonably possible — the battery can be "hot changed" while the DT100R is plugged into LocoNet.

LocoNet ID Change
Normally, a DT100R accepts and uses the LocoNet ID offered by the compatible radio receivers it sees when connected to LocoNet. The DT100R may be used to change LocoNet to a different ID (for example, to allow for 2 clubs at the same train show). To do this use the following procedure:

LOCO mode is the default mode for the DT100R since this mode runs the trains. If you change to SWITCH or MU mode and don't do anything, the throttle will switch back to the default LOCO mode in about 6 seconds.

Digitrax Command Stations (DCS050, DCS100, DCS200, DB150) have a decoder address range from 01 to 9980, plus address 00 for analog locomotives. The address range is broken down as follows:

Note:

Digitrax Command Stations utilize Mixed Mode hexadecimal addressing for addresses from 100 to 128. Mixed Mode addresses are considered as 2 Digit Short Addresses for programming purposes. The conversion from decimal to Mixed Mode addresses is shown in the following table.

The following table provides the information needed to select locomotives and operate trains using the DT100R throttle. Note: since the North Raleigh Model Railroad Club does not recommend using aliased addresses, detailed information on aliases and alias addressing is not provided. The topic of Advanced Consisting will be added at a later date.

This section will be added later.

The DCS050, DCS100 and DCS200 Command Stations have a built-in Service Mode programmer that lets you read back and write decoders on a separate electrically isolated programming track, which means programming can be carried out at the same time as layout operations. The Service Mode programmer can be accessed by any DT100 family throttle connected to the Command Station.

The DCS100/DCS200 implement 3 different methods of Service Mode programming as well as Operations Mode programming (which permits changing CV values while a locomotive is on the layout tracks). The 3 types of Service Mode programming (Paged – most common; Physical – least sophisticated; Direct) are defined in NMRA RP-9.2.3, and are provided to ensure the ability to program DCC-compatible decoders from all DCC manufacturers who support this RP.

When the DT100R enters programming mode, the current Programming method it is using is displayed on the LCD screen:

When the DT100R is in programming mode, pushing the button will cycle among the 4 programming modes. When you exit programming, the DT100R retains the last programming mode used as well as the last CV number and its data value. The next time programming mode is entered, you will be at the same place you left off.

Service Mode Programming

The DT100R must be connected to LocoNet to perform this function.

The most commonly used CVs for basic locomotive operations are the following:

The following table lists some of the common hexadecimal (hex) values used in the Configuration Register CV29 and their meaning:

Refer to the decoder manual for a list of the CVs covered by the decoder as well as a complete listing of CV29 values.

 
Operations Mode Programming

Operations Mode programming permits the programming of CVs in FX-decoder equipped locomotives while they are on the layout tracks, rather than requiring them to be on a programming track. Thus the acceleration rate (CV03) and/or the deceleration rate (CV04) of a locomotive can be changed to simulate the weight and braking power of the train to compensate for a changes in the number of cars and locomotive units. The FX parameters CV49 – CV53, and CV62 and CV63 can also be modified using Operations Mode programming.

Operations Mode programming can be performed by any DT100 family throttle at any time since the throttles are not competing for use of the single programming track.

Operations Mode programming can be carried out in radio mode (tetherless) except there will be no return or feedback messages.
 

This section provides information on maintaining and troubleshooting problems that may be encountered with the DT100R throttle. It is based on experience and a great deal of correspondence on the Digitrax Email list on yahoogroups.com.

Battery
A good battery is key to successful operation in the radio (tetherless) mode. A battery is not needed when the DT100R is plugged into LocoNet. Whatever may appear to be wrong with a DT100R throttle, the first thing to suspect is the battery. Replace the 9V battery with a new or known good battery. Try two or three batteries before deciding there is a fault with the DT100R. Examples of problems caused by weak or dying batteries include:

• The DT100R operates correctly when plugged into LocoNet, but you cannot control the train after it is unplugged.

• The throttle loses control of a train after a period of time. See also "Other problems" below.

• The throttle makes beeping noises.

Don't assume that a newly purchased battery will always be a good battery. A new battery can have a high internal resistance that prevents it from putting out sufficient voltage and/or current to operate the DT100R. Always purchase batteries from a store that sells lots of batteries and therefore always has fresh batteries on hand. Batteries have a "shelf life" as they will deteriorate even if not used.

Do not use rechargeable batteries with the DT100R. Use only alkaline batteries.

No Radio Operation
If the throttle operates correctly when connected to LocoNet but not when untethered, even after ensuring the battery is good, the problem may be that radio transmission has been turned off (secondary option set to 2n). Reset the throttle to normal radio mode either by removing the battery, waiting about 30 seconds, then replacing the battery, or by pressing the , and buttons simultaneously. Either action will reset the throttle to its default values of 01:03. Be sure to release all addresses from the throttle knobs before doing this.

Check that when you first plug in the DT100R to LocoNet, the display says rA:0n where n is a number. This indicates the UR91 is operating correctly.

Another reason is that there are no other throttles still plugged into LocoNet. When a throttle is plugged into LocoNet, the red and green LocoNet wires (wires 3 and 4, the center two) get shorted together, but if there are no throttles or other similar devices plugged into LocoNet they are no longer shorted. The UR91 receiver and the DCS100/DCS200/DB150 Command Stations only use pin 3 (the red wire) for communications. You can either leave a throttle plugged into LocoNet or create a stub cable with pins 3 and 4 connected together.

Throttle Knobs
The throttle knobs are held in place by two 0.050" screws, which can work loose over time. The screws require a 0.050" Allen wrench to tighten them. When tightening the screws, be careful not to put too much sideways pressure on the knob, as the encoder shaft can be damaged.

Encoders
A defective encoder will show itself as an erratically acting throttle knob where the locomotive speed appears to jump all over the place. The encoder cannot be repaired and must be replaced. You can either return the throttle to Digitrax for service, or you can install a new encoder yourself.

Before returning the throttle to Digitrax or replacing the encoder yourself, take a look under the knobs on your encoders. Earlier versions of the DT100R throttles have a nut around the encoder shaft. If these nuts get tight on the bushing, they tend to pull the encoder or at least strain it away from the internal printed circuit board, causing a problem with contact on the circuit board. If your throttle has these nuts on the encoder shafts, remove the knobs and then the nuts. Re-attach the knobs and test the throttle.

The encoder is available from Digikey (www.digikey.com). The Digikey part is a Bourns encoder, part number 3315Y-1-006-ND (with plastic bushing) or 3315Y-2-006-ND (with nickel-plated brass bushing). The latter is the preferred part. Digikey's description for the encoder is: ENCODER 9MM SQ VERTICAL. Detailed instructions for replacing an encoder are provided below.

Dropping the DT100R Throttle
This is something you should take extreme care not to do, especially if the floor is hardwood, tile or concrete. Depending on the angle at which the throttle hits the floor, the result can be any or all of a damaged or broken encoder shaft, a broken battery spring connector, cracked case, an internal integrated circuit dislodged from its socket or all of the above.

If you drop your throttle, first examine it carefully for obvious damage, such as a broken or bent encoder shaft. Then plug it into LocoNet and test to see if everything works as it should. If it does work properly, unplug from LocoNet and test again in radio mode. If everything still works properly you can start breathing again and remind yourself to be more careful in the future.

If it does not work, the following are the guidelines to repair any damage, or get it repaired:

• A cracked or broken case can be taped together if possible. For replacement, send the throttle to Digitrax.

• A broken battery clip must be replaced to ensure good contact with the battery terminal. Either obtain a set of clips from Digitrax and repair it yourself (does not require opening the case) or send the throttle to Digitrax for repair.

• A damaged/broken encoder must be replaced. See the section on Encoders above.

• If the throttle LCD display shows hieroglyphics and/or displays SE:1, and/or the throttle emits a clicking or buzzing sound, check that the integrated circuit ("chip") inside the case is properly seated in its socket. This chip can work loose if the throttle is dropped. The piezzo buzzer inside the throttle normally makes clicks when turning the throttle knobs, and when the chip comes loose from its socket the buzzer often makes a continuous buzz. Instructions for opening the case are provided under "Encoder replacement" above.

RJ12 Plug
There are 3 potential problems relating to the RJ12 plug on the end of the stubby LocoNet cable:

• The locking tab breaks off,
• The contacts on the plug are bent or otherwise damaged (rare), or
• The wires are not making a good connection with the contacts in the plug.

The solution to any of these problems is to replace the RJ12 plug. To do this you will need a supply of RJ12 plugs (Radio Shack Cat. No. 279-421), wire-cutters and a 6-wire crimping tool (Radio Shack Cat. No. 279-388, and others). Proceed as follows:

Other Problems and Sources
A number of other problems may appear to be associated with the DT100R throttle, but can actually be caused by other components in the DCC system. These problems include the DT100R working when connected to LocoNet but not in radio mode, runaway locomotives, lost decoder programming, poor radio response, throttle crosstalk and others.

The first thing to do is ensure the DT100R is not the problem, especially if no other DT100R's are experiencing any problems. Remove the DT100R from LocoNet and then remove the battery. Wait about 30 seconds. Install a known good battery, but do not touch any buttons. The throttle should initialize to factory defaults of primary option 01 and secondary option 03, which sets the throttle to 128 speed steps and normal radio mode. Test the throttle both connected to LocoNet and tetherless.

If the throttle still does not operate correctly, and especially if other DT100R throttles are experiencing problems, then check the following:

• Check the UR91 radio receiver(s) to ensure its PS12 (or equivalent) power supply is connected. If the UR91 power supply is OK then press the reset button on the UR91. If this doesn't work and other DT100R throttles are experiencing problems it is possible that LocoNet has gone into an unstable state. Disconnect LocoNet from the Command Station and connect a LocoNet cable directly from the UR91 to the Command Station (either Jack A or B). Using a second DT100, DT100R or DT100IR throttle, plug it into LocoNet at the UR91 jack. Now test the suspected DT100R. If it works properly then the problem is in LocoNet, and it must be found and fixed. If the DT100R still does not work, the problem may be the UR91 or the Command Station, but since earlier the throttle worked when plugged into LocoNet, the UR91 receiver is the prime suspect. If possible substitute another UR91 and test again. Return a faulty UR91 to Digitrax for repair.

• Use the green LED in the UR91 as a test indicator. When normally powered the green LED will be lit. As commands are sent from the DT100R, this LED will blink in response to these commands. Outside RF interference will cause the green LED to blink with no throttle commands. If the UR91 is not responding as throttle commands are being sent, the green LED will not blink. Note: this does not apply to a throttle tethered to the UR91's RJ12 jack.

• If there are UT1 and/or UT2 throttles in use on the layout, check to be sure that any Universal Panels (UP3) are powered with a PS12 (or equivalent) power supply, as the UT1 and UT2 throttles load down the LocoNet voltage.

• If none of the above work, then there is probably a defective LocoNet cable. A defective cable is found by disconnecting LocoNet at the Command Station, testing with a throttle, then working your way outwards from the Command Station until the faulty cable is found. The Digitrax LT1 LocoNet tester can be used in place of a throttle.

• The last item to try is a full reset of the Command Station to its factory default values. This is done be resetting OPSW #39. Refer to the Command Station manual for the procedure.

Throttle Response Delays
There will occasionally be a lag in response between when the knob on a DT100R is turned and the locomotive responds. A properly operating DT100R throttle and UR91 radio receiver should have no real delay, and should operate virtually the same as a tethered throttle. A delay of more than 1 second is definitely a problem.

There are a number of potential areas where the environment or specific actions can cause problems:

• Do not use analog address 00 when operating with radio throttles. The use of address 00 eats up system bandwidth at a rapid rate and causes response delays in other devices. This should be the first item checked when you are experiencing a delay problem. Even if you are not currently operating analog locomotives, be sure that address 00 is set at speed 00. Consider disabling analog addressing by closing OPSW #20 in the Command Station.

• At Train Shows a potential source of delay is multiple layouts using radio throttles and receivers in close proximity. Two layouts can use up to 10 throttles per receiver, but while the receivers on each layout will detect all commands from all throttles, they will only act upon those from throttles associated with the individual LocoNet connected to the layout. Too many radio signals from too many throttles can cause delays.

• Digitrax wireless throttles queue commands to minimize current drain and RF traffic. Commands are not sent while being given, only after they are complete or the queue has filled up. Thus constant throttle movement and/or function commands can cause this type of delay.
  
  The DT100R transmitter sends about 10-12 sets of instructions to the receiver for every change in throttle speed or function. These are sent in a randomly generated sequence and are sent several times with a random amount of time between them so that signals from more than one throttle will not get there at the same time (collision avoidance). This is why so many throttles can be used with one receiver. The multiple sets of instructions guarantee that at least one good set gets through; sometimes it may be the first set and other times the last set, potentially with a delay. The UR91 responds to the first throttle from which it detects a signal.

• Large metal areas (metallic walls and backgrounds, HVAC ducts, metal pipes, etc.) in the room or hall can cause reflections or ghosting of the RF signal. The UR91 receives all and must sort out the actual RF from the ghosted RF, causing some delay. (It is this ability to sort out real from ghost RF, plus communicate across LocoNet with other UR91s that allows multiple UR91 receivers on the LocoNet.)

• A poorly tuned UR91 and/or DT100R throttle can cause problems. If you are experiencing delays and the small round sticker on the UR91 is A, B or C, return the receiver to Digitrax for tuning. At the same time return any DT100R throttles that are having a problem with that receiver.

• Most layouts can get by very well with a single UR91 receiver. Be sure the antenna wires are straight and oriented at about 20° from the vertical in a "V". Also be sure to hold the DT100R in a slightly up position from horizontal and about 8"-10" away from the body. Under poor reception conditions, commands may need to be received by more than one UR91 receiver to get a clear or understandable RF signal.

• Mount the UR91 receiver as high as practical and at least 1-2 feet away from other layout wiring.

• Be sure the room temperature is at least 60°.

• Digitrax suggests a limit of 10 DT100R throttles per receiver, but more can be accommodated depending on the specifics of operation of the layout. Too many throttles will result in noticeable delays.

It is highly suggested that ballistic tracking be turned off on DT100R throttles used in the tetherless mode.

The following references have been extensively used in the preparation of this material:

• Chief Starter Set, DCS100 Command Station & DT100IR Handheld Throttle Users Manual. Published by Digitrax, Inc. 02/99.

• DT100R Radio Equipped Throttle Users Manual & UR91 Radio Receiver Users Manual. Published by Digitrax, Inc. 4/98.

• Model Railroading with DCC — Don Crano. Click here.

• John Hills' Model Railroading Web-site.

• Correspondence on the Digitrax Users and N-Scale DCC (ndcc) Email lists on yahoogroups.com

• Digitrax Users Problem Log (DUPL) on the Digitrax Users Email list on yahoogroups.com

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Last updated: Saturday July 4, 2009

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