Non-Sound Decoder MX600 - MX638 and Sound Decoder MX640 - MX659 Page 45
See chapter
5.4 “Basic settings independent of powertrain”
Chuff sound
frequency with
“virtual cam sensor“
also see CV #354 in
this table
(chuff frequency at
speed step 1)
CV #267 is only active if CV #268 = 0:
Chuff beats follow the “virtual cam sensor”; an ac-
tual cam sensor is not needed in this case.
The default setting “70” results in about 4, 6 or 8
chuffs per wheel revolution, depending on the
chuff set selected; because it also depends in
large part on the motor and gearbox used, an in-
dividual adjustment is necessary in most cases in
order to achieve the exact chuff frequency. This is
the purpose for CV #267:
The lower the value the higher the chuff frequency
and vice versa. The setting should be performed
at a low speed (around speed step 10), but not at
the lowest speed step 1.
Switching to real
cam sensor
and
trigger count for chuff
rate
and
Special function for
“Simple articulated”
steam engines
= 0: “Virtual“ cam sensor is active (to be adjusted
with CV #267, see above).
= 1: real cam sensor is active (connected to
switch input 2 of the MX640, see chapter 6);
each negative spike results in a chuff beat.
= 2, 3, 4 … real cam sensor, several triggers in
sequence (2, 3, 4 …) result in one chuff beat.
= 128 (Bit 7=1 with “virtual” cam sensor): second
driver is a bit slower; only meaningful if a
second sound sample is available in the
sound project.
= 192 (Bit 6 and 7 = 1): When no separate sound
sample is available for the second driver, the
same sample is played back for the second
driver albeit a bit slower.
Bit 7 = 1 (with real cam sensor, see above for val-
ues):
Cam sensor for driver 1 on IN3 (as usual),
Cam sensor for driver 2 on IN2 (only possible
if decoder has 2 inputs).
A typical sound signature of a passing steam en-
gine is that one chuff out of a group of 4 or 6
chuffs is louder in volume than the rest; this effect
is already part of the chuff set but can be further
amplified with the help of CV #269.
PROJECT
not functional yet:
Longer chuff length
at very low speeds
PROJECT (not yet implemented):
The chuff sounds of a real engine are extended
when driving at very low speeds due to the me-
chanical valve control. This effect can be more or
less accentuated with CV #270.
Overlapping effect at
high speed
0 – 255
(useful
up to @
30)
The individual steam chuffs of a real engine over-
lap each other at high speed. Because the fre-
quency of the chuffs increases but won’t shorten
to the same extend they will eventually blend in to
a weakly modulated swoosh.
This is not always desired in model railroading
because it doesn’t sound that attractive, hence CV
#271, with which an adjustment is possible to
have the chuff beats accentuated at high speed or
rather fade away.
Blow-off duration
also see CV #312
(blow-off key)
Opening the cylinder valves on a prototype steam
engine for the purpose of water drainage is entire-
ly up to the engineer. An automated draining at
start-up is more suitable in model railroading; CV
#272 defines how long after start-up the blow-off
sound should play.
Value in CV #272 = time in tenths of a second!
Note: If the blow-off sound is also allocated to a
function key (as delivered on F4, see CV #312),
the automated blow-off sound can be shortened
or extended with the relevant function key. Auto-
mated blow-off and function key blow-off are inevi-
tably the same (as per selection/allocation).
= 0: no blow-off sound playback
Start-up delay
during blow-off
Opening the cylinder valves and with it the related
blow-off sound on a real steam engine starts most
often before the engine even starts to move.
This can be imitated with CV #273 by automatical-
ly delaying the start of the locomotive.
This effect is cancelled when a shunting function
with momentum deactivation is being activated
(see allocation of F3 or F4 in CV #124!)
= 0: no delayed start
= 1: Special setting for blow-off via speed
regulator; no start-up delay, but setting the
speed to the lowest speed step causes the
blow-off sound to be played without powering
the motor (only with 128 speed steps).
= 2: Start-up delay in tenths of a second,
Recommendation: no values > 20 (> 2 sec)
Blow-off schedule
start-up whistle
schedule
Constant opening and closing of the cylinder
valves in real shunting operations, that often re-
quires many short trips with associated idle times,
is usually omitted. CV #274 causes the blow-off
sound to be suppressed if the engine wasn’t
standing still for the time defined here.
Value in CV #274 = time in tenth of a second!
The same stop-time is also used for the start-up
whistle!
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