Non-Sound Decoder MX600 - MX638 and Sound Decoder MX640 - MX659 Page 31
which defines the PWM duty cycle (Pulse Width Modulation; the dimming is also effective when con-
nected to the positive terminal of a low-voltage function output). Of course, this kind of voltage reduc-
tion is interesting because it is easy to change at any time by changing the value in CV #60.
NOTE: Bulbs with voltage ratings as low as 12V can be dimmed with this PWM dimming function with-
out damage even if track voltages are considerably higher; but
not
bulbs rated below that such as 5V or
1.2V bulbs. These must be connected to one of the decoder’s low voltage supply pins instead of a
“normal” positive pin (see chapter “Installation and Wiring”).
LED’s, on the other hand, always require a series resistor; if however, a resistor is selected that lowers
the voltage to 5 V, the PWM dimming can also be used even at a track voltage of 25V (in this case the
setting would be CV #60 = 50, so a reduction to one fifth).
CV #60 affects all function outputs but specific outputs can be excluded from the dimming function,
us
ing the dim mask CV’s (see table).
CV
Denomination
Range
Default
Description
#60
Reduced function output
voltage
(Dimming).
Affects all
function outputs.
0 - 255
0
Reduction of function output voltage with PWM (pulse-
width modulation). Useful for headlight dimming for
example.
Example values:
CV #60 = 0 or 255: full voltage
CV #60 = 170: 2/3 of full voltage.
CV #60 = 204: 80% of full voltage.
#114
Dim Mask 1
=
Excludes certain
function outputs from
dimming per CV #60.
For higher function
outputs go to
CV #152.
Bits
0 - 7
0
Enter function outputs that are
not
to be
dimmed
by
CV #60. These outputs will receive the full voltage
from the pin they are connected to that is, either full
track voltage or low voltage from a low-voltage pin.
Bit 0 - front headlight,
Bit 1 - rear headlight,
Bit 2 - function output FO1, Bit 3 - FO2,
Bit 4 - function output FO3, Bit 5 - FO4
Bit 6 - function output FO5, Bit 7 - FO6
Respective Bit = 0: Output will be dimmed to the value
defined in CV #60.
Respective Bit = 1: Output will not be dimmed.
EXAMPLE:
CV #114 = 60: FO1, FO2, FO3 and FO4 will not be
dimmed; front and rear headlights will be dimmed ac-
cording to CV #60.
#152
Dim Mask 2
(Excludes specific func-
tion outputs from dim-
ming as per CV #60)
Continuation of
CV #114
and
FO3, FO4 as direction
bit mapping
Bits
0 - 5
and
Bit 6,
Bit 7
0
0
… Continuation of CV #114.
Bit 0 - function output FO7,
Bit 1 - function output FO8,
Bit 2 - function output FO9,
Bit 3 - function output FO10,
Bit 4 - function output FO11,
Bit 5 - function output FO12.
Bit 6 = 0:
“normal“
= 1:
“Direction bit” to FO3 and FO4 that is,
FO3 is switched on when driving in reverse,
FO4 when driving forward (normal mapping
for FO3 and FO4 is cancelled).
Bit 7 = 1: “Direction bit” for FO9 in Fwd direction.
Low/high beam mask
One of the function keys F6 (CV #119) or F7 (CV #120) can be defined as a low beam key.
Selected function outputs can be dimmed as required with the function turned ON or OFF (inverted
action with Bit 7).
CV
Denomination
Range
Default
Description
#119
Low beam mask for F6
-
Output assignment for
(example) low/high
beam
headlights
ATTENTION:
Certain settings in
CV #154 (Special output
configurations for OEM
projects) change the
meaning of CV’s #119
and #120 and therefore
will no longer be a low-
beam mask.
Bits
0 - 7
0
Selected outputs will dim, according to the dim value
in CV #60, when the F6 key is actuated.
Typical application: Low/high beam
Bit 0 - front headlight,
Bit 1 - rear headlight,
Bit 2 - function output FO1,
Bit 3 - function output FO2,
Bit 4 - function output FO3,
Bit 5 - function output FO4.
Respective Bit = 0: Output will not be dimmed,
Respective Bit = 1: Output will be dimmed with F6 to
value defined in CV #60.
Bit 7 = 0: normal action of F6.
= 1: inverted action of F6.
EXAMPLE:
CV #119 = 131: Function key F6 toggles headlights
between low and high beam.
#120
Low beam mask for F7 Bits 0 - 7
Same as CV #119 but with F7 as low beam key.
A “second dim value” with the help of the uncoupler CV
If more function outputs need to be dimmed than CV #60 allows or if some function outputs require a
different voltage and the uncoupler function is not needed on the same vehicle then
CV #115
can be used for an alternative dimming configuration. The respective function outputs must be de-
fined as “uncoupler output” in the corresponding
CV’s #127…#132, #159 and #160
(see “Special effects for function outputs).
CV
Denomination
Range
Default
Description
#115
Uncoupler control
or
Second dim value
0 - 9
0
Only active
if “uncoupler” function is selected (value
48) in
CV #125 …132, 159 or 160:
Tens digit = 0: when used for dimming applications
Ones digit (0 to 9): PWM
– voltage reduction
(0 to 90%)
