Large-scale Decoder & Sound Decoder MX695, MX696, MX697, MX699 Page 27
The asymmetrical DCC signal stop mode needs to be activated in the decoder with CV #27.
Normally Bit 0 is set, that is CV #27 = 1, which results in the same directional control as the
“Gold” decoder from Lenz.
The asymmetrical threshold (0.4V by default) can be modified with CV #134 if necessary (i.e. if
the DCC signal of a given command station is already offset to begin with). At the time of this
writing, the “asymmetrical DCC signal” has not been standardized and many DCC systems
pay no attention to this feature.
NOTE: ZIMO decoders do not support the usual ABC slow speed step as used by
Lenz (with Lenz-Module BM2 for instance).
Position dependent
stops
with asymmetrical DCC
signal
(Lenz “ABC” method)
Bit 0 = 1: Stops are initiated if voltage in right rail
is higher than left rail (in direction of
travel). This setting, CV #27 = 1, IS THE
COMMON APPLICTION for this
feature (provided the decoder is wired
to the rail correctly).
Bit 1 = 1: Stops are initiated if voltage in left rail
is higher than right rail (in direction of
travel).
Stopping is directional if only one of the two bits is set
(not both). Traveling in the opposite direction will have
no effect. Use the other bit In case the train stops in
the wrong direction!
Bit 0 and Bit 1 = 1 (CV #27 = 3): Stops in both
directions, regardless of rail polarity.
Asymmetrical
threshold
for stopping with
asymmetrical
DCC signal
(Lenz ABC method)
1 - 14,
101 - 114,
201 - 214
=
0,1 - 1,4 V
Hundredths digit: Sensitivity adjustment, changes the
speed with which the asymmetry is being recognized.
= 0: fast recognition (but higher risk of errors,
i.e. unreliable stopping).
= 1: normal recognition (approx. 0.5 sec), fairly
reliable (default).
= 2: slow recognition (approx. 1 sec), very reliable
Tens and ones digit: Asymmetrical threshold in tenths
of a volt. The voltage difference between the two half
waves of the DCC signal defines the minimum re-
quired to be recognized as asymmetrical that starts
the intended effect (usually braking and stopping of a
train).
= 106 (Default) therefore means 0.6 V. This value has
proven itself to be appropriate under normal condi-
tions; by using 4 diodes to generate the asymmetry.
High-speed correction
for the ABC
asymmetrical stop
method
A delayed recognition (see CV #134), but also unreli-
able electrical contact between rails and wheels, have
a larger effect on a stop point at higher speeds than
at lower speeds. This effect is corrected with CV
#142.
= 12: Default. This setting usually works fine if
CV #134 is also set to default.
5.11 DC Brake Sections (Märklin brake mode)
These are the “classic” methods of automated layout control or stopping at a “red” signal. The
required settings for ZIMO decoders are spread over several CV’s.
Single Bits in each of
these CV’s are
responsible for the
correct reaction to the
DC and Märklin brake
sections.
When using track-polarity dependent DC brake
sections set
CV #29, Bit 2 = “0” and CV 124, Bit 5 = “1”!
For polarity independent DC braking (Märklin brake
sections) set
CV #29, Bit 2 = “0” and CV 124, Bit 5 = “1” and
additionally CV #112, Bit 6 = “1”!
5.12 Distance Controlled Stopping -
Constant Stopping Distance
After the type of constant stopping method has been selected with CV #140 (= 1, 2, 3,
11, 12, 13), the stopping distance will be kept as close as possible to the one defined in
CV #141,
independent of the speed at the start of the braking procedure.
This method is especially suitable in connection with automated stops in front of a red signal
(CV #140 = 1 or 11) with the help of the ZIMO HLU signal controlled speed influence or the
Lenz ABC asymmetrical DCC-signal (see above).
Although of lesser practical value, distance controlled stopping for manual driving can also be
activated (by programming CV #140 with appropriate values of 2, 3, 12, or 13), which is exe-
cuted whenever the speed is set to 0 (by the cab, throttle, computer...).
Distance controlled
stopping
(constant stopping dis-
tance)
Select a braking
method
and braking process
Activates distance controlled stopping as per CV #141
instead of time-constant braking according to CV #4.
= 1: automatic stops with ZIMO HLU (signal controlled
speed influence) or ABC (asymmetrical DCC signal).
= 2: manual stops using the cab.
= 3: automatic and manual stops.
The start of braking is delayed in all cases above (= 1,
2 or 3) when the train travels at less than full speed,
to prevent unnecessary long “creeping” (recommend-
ed).
On the other hand:
= 11, 12, 13 same meaning as above, but braking
always starts immediately after entering the brake
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