Lenz Elektronik Digital plux BM3 User manual

BM3 Block Section Module 1
BM3 Asymmetrical DCC Block
and Signal Module
Art. No. 22620
December 2005

BM3 Block Section Module 2
2
The ABC modules BM1, BM2 and
BM3 are designed to be used with
Digital plus by Lenz ®or other
standard digital control systems
that have received an NMRA-conformance seal. If in doubt,
ask the system supplier.
Technical Data:
The current-carrying capacities stated below may not be
exceeded as this could damage the block section module!
Maximum
continuous current-
carrying capacity
3.0 A
Dimensions 70 x 60 x
20 mm
Requirements for using the ABC technology
To use the ABC technology with BM1, BM2 and BM3 block
section modules, you will need GOLD or SILVER series
locomotive decoders or other decoders that support
Asymmetrical DCC.
How does the ABC technology work?
ABC manages to accomplish just what model railroaders
crave, precise on-the-spot stopping in front of signals, slow
approach and passage in the opposite direction.
By means of simple modules, which supply the braking
section in front of a signal, an asymmetry is created in the
otherwise symmetrical digital track voltage. Naturally, this
occurs only if the signal is at "Stop". This asymmetry
informs the locomotive decoder about the signal status: A

BM3 Block Section Module 3
"Stop" signal indicates an asymmetry - the train will stop or
slow down.
Additional advantages of the ABC technology:
•All locomotive functions (e.g. front lighting) can still be
switched while the locomotive stops in front of the signal.
•Programming in operational mode (POM) possible.
•The locomotive can reverse away again from the signal!
•A locomotive can pass in the opposite direction, even if
the signal is at "Stop".
•Shunting is possible, even if the signal is at "Stop".
Simply activate the shunting mode!
•No short-circuits when crossing section points between
the driving and stopping sections.

BM3 Block Section Module 4
4
Using the BM3 block section module
The BM3 block section module uses the ABC technology to
facilitate the simply construction of a block section. Each
block is equipped with a BM3 module so that an infinite
number of blocks can be added.
The BM3 block section module is used to control the block
signals. You can connect light signals directly; signals with
double-coil drive require a BMA adapter.
Control of block sections by means of BM3 modules is
suitable for push and pull operation. If you want to use rear-
powered (pushed) trains (push-pull trains, commuter trains,
motor coaches), the first coach must be fitted with a power
consumer. Simply use interior lighting or, if using a driving
coach, a function decoder for controlling the direction-
dependent front lighting.
Constructing the block section
Each block is divided into a "driving section" A and a
"braking section" B.
•The length of the driving section must be calculated so as
to fully accommodate the longest trains passing this
section.
•The length of the braking section depends on the braking
delay and/or distance set in the locomotive decoder.
Procedure:
For the following procedure, we assume that the block that is
next in the direction of travel is occupied. This means that
the train that arrives next in the present block will have to
stop.
AB

BM3 Block Section Module 5
AB
The next train arrives from the previous block.
AB
AB
When the rear-powered (pushed) train in the driving section
reaches the braking section, the BM3 switches the driving
and braking sections to asymmetrical digital voltage. As the
pushing locomotive is already located in the driving section
at that time, the GOLD decoder recognises this asymmetry
and starts to brake.
AB
AB
If the constant braking distance has been set correctly in the
decoder, the train will stop on the right spot in front of the
block signal.
As soon as the next block is clear again, the signal will
switch to "Clear" and the train will accelerate with the
starting delay set in the decoder.

BM3 Block Section Module 6
6
The above procedure requires that the first coach of the
rear-powered (pushed) train is fitted with a power
consumer, e.g. interior lighting.
Installing and connecting the BM3 module
The BM3 connections
A brief overview of the BM3 connections:
C
2
1
2 b
2 a
T
O
Figure 1
Driving section connection
Stopping section connection
Signal light GREEN (Clear)
Joint connection for signal
lights
Signal light RED (Stop)
Track connections of the amplifier
Outputs for connecting
feedback modules LR101
Signal output
Signal input

BM3 Block Section Module 7
Length of driving and braking sections
First, define the length of the driving section (A). Keep in
mind that the longest train on your layout must fit in this
section!
Then, define the length of the braking section (B) in front of
the signal. Keep in mind that the fastest train on your layout
must be able to come to a standstill within this section. Use
the feature "constant braking distance" of the
GOLD / SILVER decoder - this will ensure that all trains
will come to a complete standstill within the braking section
you have defined.
" On the right means on the right..."
... was a slogan on an Autobahn sign at the end of the 1980s.
It was meant to remind drivers to change back to the right
lane after overtaking a lorry.
The same is true when using the BM3 module: "on the right
means on the right". It is always the right rail in the
direction of travel where a rail-break is made when a driving
or braking section is defined.
Make breaks in the right rail at the beginning and at the end
of the braking section. Alternatively, you can use an
insulating track connector if there is a track joint at the point
in question.

BM3 Block Section Module 8
8
C
21
2 b 2 a
T
O
Block 1
Driving section Braking
section
C
2
1
2 b 2 a
T
O
Block 2
Driving section Braking
section
Direction of travel
Figure 2
Connecting the driving and braking section
Connect terminal (1) to the left continuous rail.
Connect terminal (2) to the right rail before the braking
section.
Connect the right isolated rail of the driving section to
terminal (2a) of the BM3.
Connect the right isolated rail of the braking section to
terminal (2b) of the BM3.
Connection to the previous / next BM3: Connecting
the signal output / input
Connect the signal input of the BM3 module that controls
section 1 to the signal output of the BM3 module that
controls section 2. Via this connection, each BM3 module
will receive information on the occupancy status of the block
that is next in the direction of travel.
Connect the signal input of the BM3 module that controls
section 2 to the signal output of the BM3 module that
controls the next block.
Continue like this to link the signal inputs and outputs of all
BM3 modules that make up your block section.
Connecting the signal
It is not necessary to connect signals in order for the block
section to function properly, but, of course, this is helpful.

BM3 Block Section Module 9
Connecting light signals
Simply connect the BM3 signal outputs to the bulbs of the
light signal. The voltage at these outputs is 15V DC. The
maximum continuous current-carrying capacity of these
outputs is 100mA. You can connect bulbs as well as
luminous diodes to these outputs. In the case of luminous
diodes, please note that terminal (C) is the plus pole.
Connecting signals with double-coil drives (form signals)
Form signals cannot be connected directly to the BM3 signal
output. The BMA adapter (art. no. 22630) is available for
this purpose. For more detailed information, please refer to
the BMA adapter operating manual.
Tips for use
Using the BM2 at the end of a block section
You can use the BM2 module to complete a block section of
BM3 modules. In a typical case, the entry signal to a station
would be at the end of a block section. By setting the entry
signal, you, as the conductor, determine whether an arriving
train may or may not enter the station.
Driving section
Direction of travel
Braking
section Driving section
Block signal Entry
signal
Braking
section
C
21
2 b 2 a
T
O C
T
O
Figure 3
The BM2 has a control output designed for this purpose.
Connect this output to the BM3 control input that controls
the previous block (All other wirings necessary for this
function are not shown in Figure 3).

BM3 Block Section Module 10
10
Controlling the entry into a block section / exit
signal
Normally, the signal connected to a BM3 module
automatically switches to "Clear" if the block that is next in
the direction of travel is clear. It is possible that you do not
want this to happen automatically because you want to
define yourself when the train should accelerate again after a
stop. Typical applications are the exit from a train station or
a stop within a block section.
If you want to prevent the block signal from switching
automatically to "Clear", all you have to do is use a switch
(K1 in Figure4) to interrupt the connection between the
signal input and the signal output of the block that is next in
the direction of travel.
Driving section
Direction of travel
Braking
section Driving section Braking
section
C
21
2 b
2 a
T
O
C
21
2 b
2 a
T
O
K1
Figure 4
As long as the switch is open, the block signal remains in the
"Stop" position. The signal will only change to "Clear" again
when you recluse the switch and the block that is next in the
direction of travel is clear. The block signal will remain in
the "Stop" position as long as the next block is occupied.
Connecting the BM3 to a feedback module LR101