INPUTS
Mark two points on straight track and time each loco crossing them.
Pass times (seconds to cross the distance)
Low (crawl)
Mid (cruise)
High (top)
Master
Slave
Run each loco at the same throttle notch for its low/mid/high pass. Longer time = slower.
Chase the master, or bring both down to the slower loco at each point.
Slave’s current speed CVs
Read these from the slave first so the suggestions scale from its real values.
RESULTS
Average mismatch
—
across low / mid / high
Verdict
—
| Point | Master | Slave | Slave vs Master |
|---|---|---|---|
| Low | — | — | — |
| Mid | — | — | — |
| High | — | — | — |
Master
Slave (as measured)
Target after matching
Suggested slave CV changes
| CV | Current | Set to |
|---|
Program the suggested values with the DCC CV Assistant, and see the Scale Converter for the scale-speed math behind these readouts.
Scale speed = measured model distance × scale ratio, over the pass time (HO = 1:87.1). Matching scales each governing CV by target speed / measured speed applied to the slave’s current CV, clamped 0–255 and kept monotonic (Vstart ≤ Vmid ≤ Vhigh). Motor response isn’t perfectly linear with voltage, so treat these as a strong first pass — re-measure and nudge once or twice for a tight match. A back-EMF-equipped decoder will match more repeatably.