ESU LokSound 5 — Configuration Reference

Reference documentation for ESU LokSound 5 sound decoders (all form factors: H0, micro, L, XL, etc.). This document is not tied to the BigFred or Loco runtime; it is intended as a future data source for decoder configuration.

Acceleration, deceleration, and speed

Shunting mode

Output mapping, brightness, and lighting effects

Digital coupler (uncoupler)

Smoke generator

Volume regulation

B — Full CV table

C — Indexed CVs

D — Long address

1. Acceleration, deceleration, and speed

1.1 Basic momentum (CV #3 and CV #4)

Acceleration and brake time are set independently:

The times are speed-dependent: at higher speeds the acceleration and braking distances are longer (the faster the locomotive moves, the longer the distance until it stops).

For braking distance independent of speed, see §1.6.

1.2 Switching acceleration / deceleration on and off

LokSound decoders can deactivate acceleration and deceleration via a function button (logic function Disable Acceleration & Braking times in function mapping). The locomotive then responds directly to the throttle — useful for shunting.

1.3 Minimum speed, maximum speed, and speed curve

LokSound 5 decoders use 256 internal speed steps, mapped to 14, 28, or 128 external steps.

Speed curve behaviour:

• CV #67 and CV #94 are fixed at 1 and 255 respectively; intermediate values (CV #68–#93) can be distributed freely.
• The speed curve cannot be switched off.
• CV #2 and CV #5 act as scale factors: reducing CV #5 squeezes the curve to a lower maximum while preserving its shape; increasing CV #2 raises the lower end.

3-point speed table (NMRA alternative)

When CV #29 bit 4 = 0, the NMRA 3-point table is active:

Always maintain: start voltage < mid speed < maximum speed. Violating this order causes erratic driving.

1.4 Brake functions (CV #179–#184)

Three brake functions can shorten the effective braking time and/or impose a speed limit:

Brake functions are cumulative — more active functions = shorter braking time. Normally they only affect braking times, not initiate braking.

Example: CV #4 = 60. CV #179 = 90 → effective braking time = 60 × (255 − 90) / 255 ≈ 39.

1.5 Load simulation (CV #103, #104)

Two logical functions — Optional Load and Primary Load — scale momentum:

Formulas:

Acceleration time = CV #3 × (load value / 128)
Braking time     = CV #4 × (load value / 128)

Only one load function is active at a time; if both are pressed, Primary Load wins. Load functions also affect sound when modelled in the sound project.

1.6 Constant brake distance (CV #254, CV #253)

Active only in brake sectors. When throttle returns to 0 outside a brake sector, deceleration follows CV #4.

Set CV #27 bit 7 to apply constant brake distance when speed step 0 is commanded (useful for computer control without physical brake sections).

1.7 Analogue operation speed (CV #125–#130)

Acceleration and maximum speed can be set separately for analogue DC and AC:

CV #129 and CV #130 define voltage offsets for function activation and motor cut-off relative to the start voltage.

2. Shunting mode

Shunting support combines speed reduction and optional momentum deactivation.

2.1 Speed trim (CV #101)

Factory default: shunting mode reduces speed to approximately 50% per step, giving finer control in the lower speed range — especially important in 14-speed-step mode.

2.2 Activation

Shunting mode is a logic function (Shunting Mode On, mapping value 2) assigned to any function key via ESU function mapping (see §3.1).

When active, the locomotive moves at the speed defined by CV #101.

2.3 Complementary shunting features

Typical shunting setup: assign one key to Shunting Mode and optionally a second to Disable Acceleration & Braking.

3. Output mapping, brightness, and lighting effects

LokSound 5 decoders provide up to 22 physical function outputs (Headlight, Rearlight, AUX1–AUX18). Headlight and Rearlight are dedicated to lighting; remaining outputs are freely assignable.

3.1 ESU function mapping overview

Unlike simple NMRA bit-mapping, LokSound 5 uses an extended mapping table with 72 rows. Each row has:

• Conditions block (input): which state triggers the action — e.g. "F3 on", "locomotive stationary, forward, F8 on".
• Output block: what happens — physical outputs, logic functions, or sound slots.

The decoder evaluates rows 1 → 72 continuously (hundreds of times per second). A row's output actions execute only when its conditions are met.

Capabilities:

• Any function button can switch multiple outputs.
• Any output can be activated by multiple buttons.
• Buttons can be combined (AND) or inverted (NOT).
• Direction of travel, movement state (moving / stopped), and up to 5 external sensors can be conditions.

Index CV access (CV #257–#511)

CVs #257–#511 are indexed — their meaning depends on index registers:

Always set CV #31 = 16 and the correct CV #32 before reading or writing indexed CVs. CVs #1–#256 are not affected by the index.

Each mapping row uses 20 control CVs (A–T): 10 for conditions, 10 for outputs. The manual's master table (pp. 75–78) lists the exact CV numbers per row.

Recommended tool: ESU LokProgrammer (software ≥ 5.0.0) — graphical mapping editor. Project-specific sound-slot assignments are listed at projects.esu.eu.

3.2 Physical output mapping values

Physical outputs are controlled via control CVs K, L, M (bit-sum encoding):

Headlight, Rearlight, AUX1, and AUX2 each have two configurations — e.g. bright upper beam (Config 1) and dim lower beam (Config 2), selected by mapping.

3.3 Function output configuration

Before use, each output must be configured with 7 CVs per output. Set CV #31 = 16, CV #32 = 0 before changing output configuration CVs.

Configuration procedure

1. Look up Mode Select value for the desired effect.
2. Compute Special Function CV 1 by adding option bit values.
3. Set Brightness (0–31).
4. Write values to the CVs for the target output (table on manual p. 85).

Example — Double Strobe on AUX4 with LED:

CV #299 (Mode Select) = 6      # Double Strobe
CV #302 (Brightness)   = 25
CV #303 (Special CV 1) = 128   # LED mode

3.4 Available lighting effects

Dimmable effects reduce to ~50% brightness when the global Dimmer logic function is active (if the output is configured for dimming).

3.5 Special output functions (non-lighting)

3.6 Special Function CV 1 — global interaction bits

3.7 Global lighting parameters

3.8 Global logic functions affecting outputs

4. Digital coupler (uncoupler)

LokSound 5 decoders can drive Krois, ROCO, and modern Telex digital couplers directly, plus run an automatic uncoupling cycle.

4.1 Coupler output mode

Set the function output to Conventional coupler function (Krois) or ROCO coupler function via Mode Select in output configuration.

PWM behaviour: The output turns on at 100% for 250 ms, then switches to a high-frequency PWM signal to avoid burning the coupler coil.

Use automatic switch-off (auto-off CV) for couplers that cannot handle permanent activation — ROCO couplers in particular. Unit: 0.4 s per step.

4.2 Automatic uncoupling — CV settings

Pull-back time should exceed push time so the locomotive stops at a safe distance from the train.

The coupler output must be configured correctly (coupler mode on the appropriate AUX output).

4.3 Automatic uncoupling cycle

The Uncoupling cycle logic function (mapping value 128 in CV O) triggers a full sequence:

1. Locomotive pushes backward against the train.
2. Coupler activates.
3. Locomotive pulls away.

Timing is governed by CV #246–#248. Map the logic function to the desired function key via function mapping.

4.4 Wiring notes

• Connect the coupler solenoid to any configured AUX output.
• Observe decoder maximum current per output (see manual §5.1.11).
• For Krois/ROCO couplers, use the dedicated coupler mode — do not use plain dimmable light mode.

5. Smoke generator

5.1 Output types and wiring

Smoke generators connect to function outputs (AUX1–AUX18). Choose the output mode matching the hardware:

LokSound 5 L supports a dedicated 6-pin synchronized smoke unit (2× fan, 2× heater, 2× temperature sensor). The decoder reads the temperature sensor and regulates heating — preventing burn-through on empty tanks. Use only ESU spare-part generators or equivalent units with temperature sensors.

5.2 Smoke configuration CVs (per output)

When a smoke mode is selected, Special Function CVs control behaviour:

Smoke unit with external control (Mode 28) — set Special Function CV 2:

5.3 Activation via function mapping

Map the logic function Smoke Units (ESU, KM-1, Kiss) (value 32 in CV P) to a function key to enable synchronized smoke generators.

For Seuthe units on a plain AUX output, configure the output mode directly (no logic function required) and assign the AUX to a function key in mapping.

5.4 Practical tuning factors

Smoke amount depends heavily on:

1. Track voltage — even 1 V difference between command stations matters.
2. Generator tolerance — Seuthe units vary significantly; distillate type and fill level matter.
3. Output brightness — primary decoder-side control (0–31).
4. Wiring — chassis-referenced wiring receives power only every second half-cycle on DCC; U+ wiring avoids this.

6. Volume regulation

6.1 Master volume (CV #63)

Effective volume of each sound = master volume × individual sound volume.

If speakers distort (especially sugar-cube types), reduce CV #63 or lower the speaker baffle height.

6.2 Per-sound volume (indexed CVs)

Each sound occupies a sound slot (1–32). Individual volumes are set via indexed CVs:

• Set CV #31 = 16, CV #32 = 1 before changing per-sound volume CVs.
• Range per sound: 0–128 (factory default typically 128 or 99 depending on slot).
• Sound-slot-to-CV mapping depends on the loaded sound project — refer to projects.esu.eu for project-specific tables (steam / diesel / electric / special).

Avoid clipping: Do not set all individual volumes to maximum if many sounds play simultaneously — summed signals can clip (clicking/popping). Balance volumes for sounds that overlap.

Example sound-slot CV layout (steam project)

Diesel and electric projects use the same indexing scheme with different function names (fan motor, compressor, doors, etc.).

6.3 Volume control during operation

Logic function — Volume control

Map the Volume control logic function (value 64 in CV P) to a function key:

• Each button press (press and release) reduces volume by one of four steps down to minimum.
• Further presses cycle back up to maximum.

Useful for on-layout adjustment without reprogramming.

Sound fader (CV #133)

Map Soundfader (value 32 in CV P) for tunnel simulation or temporary mute.

6.4 External volume control (hardware)

Wiring diagrams: manual Figures 30 and 32.

6.5 Related sound CVs

Appendix A — LokSound 5 decoder variants (overview)

Appendix B — Full CV table (CV #1–#255)

Source: manual chapter 21. LokSound 5 DCC uses 0.896 s per unit for CV #3/#4 (multiprotocol decoders: × 0.25 s). Defaults are factory values; sound-project CVs (#155–#170) vary by project.

Address and basic motor

Momentum adjustment and speed table

Configuration registers

Index registers and programming assist

Back-EMF / PID

Analogue operation

Braking, load, and consist

Sound and volume

Lighting (non-indexed)

Smoke generator

Coupler and decoder lock

Appendix C — Indexed CVs (#257–#511)

CVs #257–#511 share physical addresses; meaning depends on CV #31 (always 16) and CV #32:

Rules:

• Always set CV #31 = 16 before accessing indexed CVs.
• The same CV number (e.g. #257) has different content at different CV #32 pages.
• Function mapping uses 72 rows × 20 control CVs (A–T); see manual pp. 75–78.
• Output configuration uses 7 CVs per physical output (Headlight, Rearlight, AUX1–AUX18); see §3.3.

Per-sound volume (CV #32 = 1): set CV #32 = 1, then CV #259+ control slot volumes 0–128. Sound-slot mapping is project-specific — see projects.esu.eu.

Appendix D — Long address calculation

Long address = base (from CV #17) + CV #18. CV #17 selects the 256-address block (e.g. 207 → addresses 3840–4095). Example: address 4007 → CV #17 = 207, CV #18 = 167. See manual Figure 50.