CV Calculators

Along with the information below, we have provided some easy to use CV calculators for your convenience.

Click here to see the CV Calculators

Configuration Variables Used by Digitrax Mobile and Sound Decoders

Digitrax decoders use many different cofiguration variables (CVs) to control the operating characteristics of the decoder.  CV usage is fairly standardized from decoder to decoder but there may be differences in how CVs are used by different manufacturers.  To be absolutely sure about which CVs a particular decoder uses for a particular feature, the range of values available and the factory default value please consult the specification sheet available on each decoder's product page.  This will give you a complete list of CV uses for each individual decoder.

Note that some legacy decoders do not use the same CVs that are currently in standard use.

Configuration Register CV29 Value Table

Click here to use our CV29 Calculator

Features Controlled by CV29

  1. Speed step control:  Advanced Mode (28/128 speed steps) or Standard Mode (14 speed steps).

  2. Speed table ON or OFF

  3. Analog mode conversion ON or OFF

  4. Normal Direction of Travel (NDOT)

  5. 2 digit addressing or 4 digit addressing

The value you program into CV29 sets all of these 5 characteristics.  If you want additional information about these characteristics, it is included on this page below the calculator.

Use this calculator to select which features you want to activate and the CV29 value to program into your decoder will be displayed automatically. 

The factory default value for CV29 is 06 for all Digitrax decoders.  This means that the decoder will use advanced speed steps (28/128),  28/128 step speed tables are disabled, Analog Mode Conversion will be ON, the Normal Direction of Travel will be forward and 2 digit addressing will be used. 

If you will use 4 digit addressing, change CV29 to one of the values that allows for 4 digit addressing.  The most common setting for CV29 when 4 digit addressing is used is 038.


Speed Control

There are two modes for speed step control:  Advanced or 28/12/ speed step control or Standard or 14 speed step control.  Most modern command stations and mobile decoders use Advanced mode.  This setting should be left as Advanced unless you are using an older non-Digitrax command station.  All Digitrax command stations use Advanced mode.

If you are using an older non-Digitrax command station and/or older non-Digitrax decoders, you may need to set CV29 in your decoders to different values to match the mode of the command station you are using. If your command station is sending standard 14 speed step mode commands, your decoders must be programmed for standard mode in CV29. If your command station is sending advanced 28/128 speed step commands, your decoders must be programmed for advanced mode in CV29. 

All Digitrax decoders are 128 speed step capable and we recommend that for best performance you run them in 128 speed step mode. If you are using non-Digitrax decoders are not able to be programmed for advanced mode and you want to run your command station in advanced mode, you can "status edit" the standard decoders so that they can be run with your command station. See your starter set manual for the specifics of status editing.

Addressing

All current production Digitrax decoders are capable of both 2 & 4 digit addressing. Some older decoders can only use 2 digit addressing.

Analog mode conversion

is very convenient if you plan to run your Digitrax decoded locomotive on regular DC layouts.  With analog mode conversion enabled, the decoder will automatically begin operating as a DC locomotive when no DCC signal is detected by the decoder.  This means that if you place your Digitrax decoder equipped loco, with analog mode conversion enabled, on a regular DC layout, it will run on the DC layout.  Disabling analog mode conversion can be useful for setting up brake generator sections on the layout.  See the Tech Support Depot for more information.

Normal Direction of Travel (NDOT)

NDOT lets you set up your locos to run either long hood forward or short hood forward. Because with DCC the decoder determines which way the loco will move independent of track polarity, you can set up either direction as forward depending on the prototype. (Not all decoders have this feature so be sure to check the card that came with your decoder.)

Speed Table

Speed table can be enabled or disabled using CV29's value. Speed tables are used to customize the throttle response curve of each decoder equipped locomotive. The speed table values can be stored in the decoder by programming values into CVs 65-93. These will remain stored in the decoder even if the speed table characteristic is turned off by the value programmed into CV29. You can use CV29 to turn speed tables on and off. 
 

4-digit Address Calculator for CV17 & CV18

Click here to use our CV17 & CV18 Calculator

Programming a 4 digit address requires programming of both CV17 and CV18.  CV29, the configuration register CV must also be programmed to use the 4 digit address. 

Zephyr Xtra and systems using the DT300 and DT400 Series throttles will automatically program 4-digit address and update CV29 configuration register in a locomotive decoder with no math required. When using Digitrax throttles, AD4 appears in the display to prompt you to enter the 4 digit address you want to program. Some other systems require you to manually program the 4-digit address CVs 17 & 18 individually and update CV29 manually. If you want to program a 4 digit address you cannot simply take the desired locomotive address and split the number and stick it into CV17 & CV18.

CV61 Values: Non Directional Headlights, Transponding & Split Field Motor/AC

Click here to use our CV61 Calculator

Digitrax uses CV61 to give you the following features:

  1. Non-Directional Headlight Operation
  2. Transponding Enabled or Disabled
  3. Split Phase Motor Drive for Marklin AC and Lionel Type motors

CV61 is a manufacturer specific configuration variable. 

The look up table below shows the effects of different CV values that you can program into CV61.

The factory default Value for CV61 is 01.

If you would like additional information about these features, please scroll down below the table. 

CV 61 Value

Non-directional headlights

Transponding

Split Field Motor/AC

00

No

No

No

01

Yes

No

No

02

No

Yes

No

03

Yes

Yes

No

04

No

No

Yes

Non-directional headlight Operation Most Digitrax decoders support the independent control of the head light and tail light. In decoders with this capability, if you don't want automatic reversing headlight operation (the decoder's factory default setting), you can set up the white lead for the headlight to operate on F0 (function 0) and the yellow lead for the rear light to operate independently on F4 (function 4). This lets the engineer have complete manual control over when these lights are on.

Program CV61 to a value of 01 and the decoder will "map" the normal reverse light function lead (yellow) to be controlled by the F4 function key. In addition the normal forward light function lead (white) will become a non-directional light lead that is controlled by the F0 (light function) button on the handheld. If you have set up FX or FX3 operation for the white & yellow leads, this will continue to work. These effects can be made directional by programming an appropriate CV Value.  Program CV61 to a value of 00 and the decoder will return to automatic directional lighting with the white lead being the headlight and the yellow lead being the reverse light. The non-directional headlight feature is not available on Digitrax DN121 decoders.

Transponding Enabled/Disabled Digitrax decoders with transponding are shipped with CV61 programmed to 00 for transponding disabled. Before implementing transponding, you must enable this feature in your decoders. Transponding enabled or disabled does not affect operation on non-transponding layouts.  Transponding lets you know where on the layout specific locomotives are located.  Implementation of transponding requires instrumenting the track and enabling this feature in your decoders.

Split Field/AC Motor Drive When you program CV61 to 04 Digitrax decoders with split field motor drive capabilities will convert their motor leads to drive a "split field " AC motor instead of the default DC motor. This lets you run Marklin 3 pole AC motors and similar motors in a number of locos built in Europe with Digitrax 1.5 amp decoders. For Hi-rail AC motors, you can use Digitrax decoders rated at 3 amps or more. To use an AC motor, connect the common motor/brush to the blue (lamp common) lead on the decoder. Connect the forward field coil to the decoder's gray lead. Connect the reverse field coil to the decoder's orange lead. Be sure that any other mechanical or electrical reversing relay and/or track feeds are removed from the AC motor. The decoder's wires should be the only wires connected to the converted AC motor. Be sure all motor connections are isolated from the motor chassis. Programming decoders set up for AC operation: Once you set up your decoder to run with an AC motor by programming CV61, you must have the motor or a lamp load connected from the blue lamp common wire to one of the motor leads to do any additional programming. You can also connect a 1 k ohm resistor to the blue and gray wires to simulate the AC load to allow additional programming. 

CV19 Values: Advanced Consist Address

Digitrax decoders are capable of “advanced consisting” where the decoders themselves maintain consist information.

This makes the consists transportable from layout to layout (as long as the locomotives are put back on the track in the same configuration in which they were set up).

Advanced consisting requires that ALL decoders in the consist have decoders that are set up for Advanced Consisting. Most decoders currently on the market have this feature. Non-DCC locomotives cannot be included in an Advanced Consist.

With Advanced Consisting, program an Advanced Consist Address using CV19 and set up how the functions on locos in the consist will work using CV21 & CV22.

Digitrax command stations are capable of universal consisting where the command station maintains consist information. In the case of UniVersal Consisting, the consist is set up in the command station using your throttle. This type of consist can have any DCC decoder equipped locomotive included along with non-DCC locomotives as well.

Customers using Digitrax command stations can use either Advanced Consisting or UniVersal Consisting in operation.

CV19 is the advanced consist address.

CV19 also contains data for the direction in which the consist will operate.

See the table below to determine what value to program into CV19

CV19 Value

Effect on Advanced Consist Address

Normal Direction of Travel of Advanced Consist

000 Advanced Consist Addressing Disabled N/A
001-127 Advanced Consist Addressing Enabled Forward
129-255 Advanced Consist Addressing Enabled Reverse

When CV19 is active, the functions within the advanced consist are individually controlled at their regular addresses.

CVs 21 & 22: Advanced Consist Function Control

Click here to use our CV21 & CV22 Calculator

CV21 & CV22 allow you to control specific functions using the advanced consist address.

To determine the value to program into these CVs, add up the values of the functions you want to control in the advanced consist and program that value into the CVs.

To make all functions in an advanced consist be controlled by the advanced consist address, program a value of 255 into both CV21 & CV22.

CV21 Values

Function Value
F1 001
F2 002
F3 004
F4 008
F5 016
F6 032
F7 064
F8 128

CV22 Values

F0 forward 001
F0 reverse 002
F9 004
F10 008
F11 016
F12 032

For example: If you want to have F0, F1 and F5 controlled by the advanced consist address, program CV21 to a value of 017/x11 and CV22 to a value of  001/x0. All other functions will still be controlled by the decoder’s regular address.

CV 49-52, CV113-116 FX3 Lighting Effects Set Up

Decoders with FX3 features have 8 user configurable, independent special effects generators.  These are set up by programming CV values as described below.  All current production Digitrax decoders are FX3 capable.*

FX3 functions incorporate FX generators with additional dynamic and static qualifiers.  FX3 functions are fully mappable so they can be controlled by any function key on your system.  A master light switch can be set up to turn off all lights on a locomotive. Functions associated with advanced consists can be controlled, as well.

Setting Up FX3 Effects On FX3 Function Outputs

Each function output has an associated FX3 control CV. Using the FX3 Generator CVs table below, determine which CV is associated with the output you are using to set up an FX3 effect. For example, if you want to set up an FX3 feature on your forward headlight, you will use CV49 to control the FX3 feature for the led/lamp attached to the F0F decoder output.

Note:  For FX3 decoders, you can set up as many as 8 FX3 function outputs. All FX3 outputs can be set up with FX3 effects.  Many decoders do not have 8 function output wires attached for all functions that are available. See the specific decoder instructions to determine which "pad" on the decoder controls each function. Use thin wire or wire saved during previous decoder installations to solder function output wires to the pads associated with the function you want to use.

FX3 Generator CVs

FX3 CV# Function # Standard Output Color
CV49 F0/Light Forward (F0F) White
CV50 F0/Light Reverse (F0R) Yellow
CV51 F1 Function 1 Green
CV52 F2 Function 2 Violet
CV113 F3 Function 3 Brown
CV114 F4 Function 4 White/Yellow
CV115 F5 Function 5 White/Green
CV116 F6 Function 6 White/Blue

Each FX3 effect has a CV value that generates the effect you want on a particular output.  That CV Value also controls the FX3 effect’s operating characteristics with respect to locomotive direction and the head light (F0) function.

Use the following two tables to determine the CV value to program for each individual output lead.  Choose a value from the FX3 Effect Table and a value from the FX3 Operational Characteristics Table.  Add these two numbers together to determine the CV value to program into the CV associated with the output you are using to achieve the effect and operational characteristics you want.

For example, if you want a particular function output to remain a simple on/off output, leave it programmed to the factory default of CV Value = 00.  That is from the FX3 Effect Table a value of 0 + from the FX3 Operational Characteristics Table a value of 0 = a CV Value of 00.  This gives No FX3 effect, normal function control of lead, in forward direction the lead will be ON when the function key is ON for that output lead, effect phase A.

FX3 Effect Table

Decimal Value to Add for CV Value Computation FX3 effect generated
0 No effect, normal function control of output lead
1 Random flicker 
2 Mars light
3 Flashing head light
4 Single pulse strobe
5 Double pulse strobe
6 Rotary beacon simulation
7 Gyralite
8 Rule 17 dimmable headlight, dim when F4 is active or locomotive direction is opposite normal direction of travel (NDOT)
9 FRED or "end of train" light
10 Right ditch light on when loco is running forward and F0 is on.  When F2 is on, the right ditch light flashes alternately with the left ditch light to simulate ditch light operation at a grade crossing.
11 Left ditch light. on when loco is running forward and F0 is on.  When F2 is on, the left ditch light flashes alternately with the right ditch light to simulate ditch light operation at a grade crossing.
12-16 Digitrax reserved for effects expansion.

FX3 Operational Characteristics Table

Decimal Value to Add for CV Value Computation How the FX3 effect generated will operate
0 Forward direction, ON with function ON, effect phase A
16 Reverse direction, ON with function ON, effect phase B
32 Non directional effect, ON with function ON, effect phase A
48 Non directional effect , ON with function ON, effect phase B
64 Forward direction, ON with F0 ON & function ON, effect phase A
80 Reverse direction, ON with F0 ON & function ON, effect phase B
96 Special Logic for Fwd Ditch Light or Rule 17 dimming  Standard Ditch Light Operation
112 Special Logic for Rev Ditch Light or Rule 17 dimming  Standard Ditch Light Operation
  How the FX3 effect generated will work
160 Speed=0, non directional effect, phase A and function qualifier
176 Speed>0, non directional effect, phase B and function qualifier
192 Ditch off phase A Alternate Ditch Operation-Off when running flash on with F2
208 Ditch off phase B Alternate Ditch Operation-Off when running flash on with F2

 

*If your decoder is not a series 3 or later decoder, please check the spec sheet to determine which type of functions it supports.Typically the series number of your decoder is the 3rd digit in the part number.For example a DH123D is a series 3 decoder (D=DCC Decoder, H=Smallest Scale It Will Fit, 1=1 Amp current rating, 2=Number of function outputs available, 3=Series number, D=Digitrax JST connector to wires interface.)

The tables included in this section will NOT work for older Digitrax decoders with FX function generators.These decoders use different CVs to control their function outputs. Please see the documentation that came with these decoders for information on these CVs and how they work.There is also an article in the Tech Support Depot explaining FX function generators and their associated CVs.CV53 and CV54 are NOT used for FX3 control.

CV 62-63 FX3 Effects Rate, Keep Alive & Ditch Light Hold Over

Click here to use our CV62 Calculator

Click here to use our CV63 Calculator

CV62 lets you control the rate and keep-alive brightness for each FX3 effect you set up. The CV value for CV62 is made up of 2 digits, the first digit and the second digit.

The first digit controls the keep alive/baseline off voltage for incandescent lamps. This value should be between 0 and 15. A value of 0 gives no keep alive and a value of 15 gives maximum keep alive. Values between the high and low allow you to vary whether the lamp actually goes off between light pulses or whether it stays on very dimly or more brightly. (If you are using LEDs, the first digit for CV62 should be 0.)

The second digit controls the rate of the FX3 effects programmed. This value should be between 0 and 15. A value of 0 gives a fast rate and a value of F gives a slow rate of operation. We recommend you start with a 4 and adjust it up or down until you get the effect you are looking for.

Ditch Light Hold Over Time CV63

If you are using the ditch light effect in conjunction with F2, CV63 lets you set up a hold over time to control how long the ditch lights continue to blink after F2 turned off by releasing the key on the throttle. Remember that F2 is a momentary key on most Digitrax throttles that will keep function 2 on as long as you hold the key down and then turn function 2 off when you release the key. This allows the ditch lights to be on steady during regular operation and to begin alternate flashing when F2 (usually the horn) is activated and to continue flashing alternately for a predetermined length of time after F2 is released; just like the prototype. A value of 00 yields no hold over time, a value of 40 yields a realistic time of about 5 seconds. A value of 255 yields about 20 seconds hold over time.

CV 33-46: Function Mapping

Click here to use our CV33-CV46 Function Mapping Calculator

Function mapping allows you to set up which function outputs are controlled by which function controls on your throttle. You can even control more than one function output with one control. Use our Function Mapping Calculator to determine the CV values to program to the function mapping CVs to make the function controls on your throttle control the decoder function outputs the way you want them to work.

Decimal and Hexadecimal Numbers

Click here to use our Hexadecimal / Decimal Calculator

Decimal and Hexadecimal Numbers For Programming CV Values

Over the years, different Digitrax throttles have used a combination of decimal, modified hexadecimal and hexadecimal numbers for entering CV#s and CV values.

The following information is provided as a programming reference to show you how these different schemes work so that you will be able to use your current production and heritage throttles to program decoders.

Utility Throttles UT1, UT2 & UT4 use decimal numbers exclusively for CV#s and CV values. Because these throttles use 2 selector switches that can access the numbers 0-9, you are limited to programming only CV#s and values from 00 to 99. 

DT300 & DT400 Series Throttles use decimal numbers for entering CV#s and can use either decimal or hex for entering CV Values.  You can change from decimal to hex and vice versa by clicking the R encoder knob when you are in programming mode.  When a hex value is displayed, you will see an “x” in front of the number.  When a decimal number is displayed you will just see the three numbers.

 

DT100 Throttles use a modified hex numbering system for accessing CV#s and the CV value for the decoder address (CV01) as shown on the following table.The DT100 is limited to programming CV#s 01-128.(See your DS54 manual for special method of programming CVs related to stationary decoders that are above this range.)A 2 digit decoder address can be any decimal number from 01-128.When you use your DT100 throttle to access 2 digit addresses or CV#s, decimal numbers 00 to 99 appear in the display as 01-99 and decimal numbers 100-128 appear as listed below.For example, if want to select address 120 to run on your DT100, dial up C0. 

 

DT100 Series Throttle Display-CV# & 2 Digit Address

01-99 appears as 01-99Addresses above 99 listed below:

DEC

HEX

DEC

HEX

DEC

HEX

100

A0

110

B0

120

C0

101

A1

111

B1

121

C1

102

A2

112

B2

122

C2

103

A3

113

B3

123

C3

104

A4

114

B4

124

C4

105

A5

115

B5

125

C5

106

A6

116

B6

126

C6

107

A7

117

B7

127

C7

108

A8

118

B8

   

109

A9

119

B9

   

 DT100 Series Throttles use hexadecimal notation for all other CV Values entered.

Decimal to Hexadecimal Conversion Chart

DEC

HEX

DEC

HEX

DEC

HEX

DEC

HEX

DEC

HEX

DEC

HEX

DEC

HEX

000

x00

039

x27

078

x4E

117

x75

156

x9c

195

xc3

234

xEA

001

x01

040

x28

079

x4F

118

x76

157

x9d

196

xc4

235

xEb

002

x02

041

x29

080

x50

119

x77

158

x9E

197

xc5

236

xEc

003

x03

042

x2A

081

x51

120

x78

159

x9F

198

xc6

237

xEd

004

x04

043

x2b

082

x52

121

x79

160

xA0

199

xc7

238

xEE

005

x05

044

x2c

083

x53

122

x7A

161

xA1

200

xc8

239

xEF

006

x06

045

x2d

084

x54

123

x7b

162

xA2

201

xc9

240

xF0

007

x07

046

x2E

085

x55

124

x7c

163

xA3

202

xcA

241

xF1

008

x08

047

x2F

086

x56

125

x7d

164

xA4

203

xcb

242

xF2

009

x09

048

x30

087

x57

126

x7E

165

xA5

204

xcc

243

xF3

010

x0A

049

x31

088

x58

127

x7F

166

xA6

205

xcd

244

xF4

011

x0b

050

x32

089

x59

128

x80

167

xA7

206

xcE

245

xF5

012

x0c

051

x33

090

x5A

129

x81

168

xA8

207

xcF

246

xF6

013

x0d

052

x34

091

x5b

130

x82

169

xA9

208

xd0

247

xF7

014

x0E

053

x35

092

x5c

131

x83

170

xAA

209

xd1

248

xF8

015

x0F

054

x36

093

x5d

132

x84

171

xAb

210

xd2

249

xF9

016

x10

055

x37

094

x5E

133

x85

172

xAc

211

xd3

250

xFA

017

x11

056

x38

095

x5F

134

x86

173

xAd

212

xd4

251

xFb

018

x12

057

x39

096

x60

135

x87

174

xAE

213

xd5

252

xFc

019

x13

058

x3A

097

x61

136

x88

175

xAF

214

xd6

253

xFd

020

x14

059

x3b

098

x62

137

x89

176

xb0

215

xd7

254

xFE

021

x15

060

x3c

099

x63

138

x8A

177

xb1

216

xd8

255

xFF

022

x16

061

x3d

100

x64

139

x8b

178

xb2

217

xd9

   

023

x17

062

x3E

101

x65

140

x8c

179

xb3

218

xdA

   

024

x18

063

x3F

102

x66

141

x8d

180

xb4

219

xdb

   

025

x19

064

x40

103

x67

142

x8E

181

xb5

220

xdc

   

026

x1A

065

x41

104

x68

143

x8F

182

xb6

221

xdd

   

027

x1b

066

x42

105

x69

144

x90

183

xb7

222

xdE

   

028

x1c

067

x43

106

x6A

145

x91

184

xb8

223

xdF

   

029

x1d

068

x44

107

x6b

146

x92

185

xb9

224

xE0

   

030

x1E

069

x45

108

x6c

147

x93

186

xbA

225

xE1

   

031

x1F

070

x46

109

x6d

148

x94

187

xbb

226

xE2

   

032

x20

071

x47

110

x6E

149

x95

188

xbc

227

xE3

   

033

x21

072

x48

111

x6F

150

x96

189

xbd

228

xE4

   

034

x22

073

x49

112

x70

151

x97

190

xbE

229

xE5

   

035

x23

074

x4A

113

x71

152

x98

191

xbF

230

xE6

   

036

x24

075

x4b

114

x72

153

x99

192

xc0

231

xE7

   

037

x25

076

x4c

115

x73

154

x9A

193

xc1

232

xE8

   

038

x26

077

x4d

116

x74

155

x9b

194

xc2

233

xE9

   

Notice that when using Hex numbers, the 6 and b look very similar in the throttle display so be careful that you are programming the value you want.