Page 40 Non-Sound Decoder MX618 - MX634 and Sound Decoder MX640 - MX648
…. the upper or lower end of a CV value range is reached!
If RailCom is not available (because the system used is not equipped with RailCom), the value of a
particular CV can only be determined by reading it out on the programming track.
Although, most of
the time this is not necessary since the reaction to a changed CV value can immediately be heard by
the changing sound.
Note: With the MXDECUP update module it is possible to read-out and write complete CV and pa-
rameter sets and if necessary edit them on a computer!
5.3 The test run
for determining the motor’s basic load
The following procedure enables the (subsequent) adjustment of driving sound to engine load (i.e.
inclines, pulling weight
…), such as steam chuffs (volume and sound) with the CV’s #275, 276…
Technical background:
The load-dependent sound is based on EMF (Electro Motive Force) measurements inside the decoder, which is
primarily used for keeping the motor speed constant during load changes. Before the decoder can produce the cor-
rect sound for the respective driving conditions it has to know first what these measurements are at normal
“no-load”
cruising speed (smooth rolling of the engine or train on straight and level track). This
“basic load” of an engine or
train is often considerably higher on model trains than on the real railroad, which is due to gearbox losses, power
pick-ups etc.
Deviations from this “basic load” will then be interpreted as inclines or declines, which triggers appro-
priately modified chuff sounds.
Initiated by
“Pseudo-Programming” in Operations Mode
CV #302 = 75
an automated test run is performed to record the “basic load” factor in forward direction;
ATTENTION: the engine (or train) is
driven automatically
in forward direction for which unoccupied
track must be available of
at least 5 meters (15 feet),
with absolutely no inclines or declines and
without any (tight) curves.
With
CV #302 = 76
an automated recording run is performed in reverse direction, for locomotives that have different
“basic loads” in this direction (otherwise, the basic load in reverse is considered identical to forward).
The measured results are stored in
CV’s #777 and 778
(slow/fast PWM values, forward) and
#779
and 780
(PWM values
in reverse direction); these CV’s can be read out and used as needed for other
vehicles, or used as base for further tests.
Note: A “heavy” train (a train with higher rolling resistance due to power pickups of lighted coaches for
example) may have a different “basic load” than an engine with nothing on the hook. A separate re-
cording run may be required for such situations in order to obtain the best load dependent sound.
5.4 Basic settings independent of powertrain
The CV’s in the following table have the same meaning for all types of power (Steam, diesel, electric):
CV
Designation
Range
De-
fault
Description
#265
#266
#395
#396
Select loco type
For sound collections; see first page of this chapter (5.)
Total volume
0-255
=
0-400%
64
=
100%
The default value “64” results in the (
mathematically)
high-
est possible distortion-free playback volume; but values of up
to 100 may nonetheless be practical.
Recommended: #266 = 40…90
Maximum volume the sound can be raised to (does not have
to be the same value as in CV #266
Defines function key for volume decrease; lowers volume as
long as key is pressed; about 10 steps/sec, down to 0.
ATTENTION: This changes CV #266.
#397
Defines function key for volume increase; raises volume as
long as key is pressed; about 10 steps/sec, to the maximum
defined in CV #395.
ATTENTION: This changes CV #266; can be used as a sub-
stitute for a mute key.
#310
ON/OFF key for
engine and random
sound
0 - 28,
255
8
Defines the function key (by default F8) that turns the engine
sound (chuffs, boiling, blow-offs, brake squeals...) as well as
the random sound (compressor, coal shoveling...) ON or OFF.
= 8: F8 key switches driving sound ON or OFF.
Note: this is the default key for ZIMO original sound projects;
OEM projects (i.e. ROCO) often use other settings. Most of-
ten 1 for the F1 key.
= 1…28: ON/OFF key for F1…F28.
= 255: engine and random sounds are always ON. (If not,
change CV #313!).
#311
ON/OFF key for
function sound
0 - 28
0
Function key assigned as ON/OFF key of function sounds
(i.e. F2
– whistle, F6 – bell etc.).
= 0: does not mean that F0 is assigned for this task but rather
that the function sounds are always active.
= (#310), if the same value is entered here as in CV #310, the
key defined in #310 turns all sound ON/OFF.
= 1 ... 28: Separate ON/OFF key for function sound.
#312
Blow-off key
0 - 19
4
=
F4
See chapter 5.5 “Basic steam engine settings”.
(does not belong in this chapter, despite the correct number sequence)
NOTE: The
default values
of individual CV’s are
NOT decoder-specific,
but rather depend on
the decoder’s
sound project.
This means that a HARD RESET with CV #8 = 8 returns the
decoder to the state defined by the sound project. The default values listed below are values
often used in sound projects, but not necessarily the correct values in all cases.
