LDT Digital-Professional Series Operating Instruction page 2

feedback modules RM-DEC-88(-Opto) and RM-88-N(-Opto) or
s88 feedback modules of other manufacturers.
The address of the feedback modules is related to the
sequence of the connection to the digital central unit or to the
interface. The feedback module which is directly connected
to the central unit will get always the address 1. Further details
are available within the operation instructions of your digital
central unit or the interface.
The RM-GB-8-N contains two 6-poles pin bars for the s88-
standard connection and two RJ-45 sockets for a bus
connection in accordance to
At the RM-GB-8-N are the pin bars and sockets marked with
OUT and IN.
OUT is the connection in direction of the digital central unit
or interface. IN shall be connected to the next following
feedback module within the s88 bus line.
Digital central units and interfaces contain always a s88-input
for a s88-standard connection.
We supply an interference protected twisted s88-bus-cable
with original s88-bus plugs for the s88-standard connection.
The plugs of the s88-bus-cable are correct assembled on the
6-poles pin bar of the RM-GB-8-N when the position of the
white single wire corresponds to the white marking on the pc-
board next to the pin bar. The cable shall lead directly away
from the feedback module. Additionally attend to the correct
position of plug to prevent any offset to the 6-poles pin bar.
For a secure s88-bus connection in accordance to
an interference protected blue patch cable with RJ-45 plugs.
Attention: Digital central units with PC-network connection
(e.g. Central Station 1, 2 and 3 and ECoS) contain as well a RJ-
45 socket. The RJ-45 network socket shall never be
connected to the RM-GB-8-N!
The RM-GB-8-N shall be operated only with a s88-bus voltage
of 5V. If the Digital-command station or the Interface offers the
possibility to use either 5V or 12V for the s88-bus voltage the
5V has to be selected. The operation of the s88-connection at
the bottom of the Märklin CS3 plus (60216) with a constant s88-
bus voltage of 12 Volt will not be permitted because this will
damage the feedback module. It is absolutely required to set
the Märklin L88 (60883) sliding switch onto a s88-bus voltage
of 5Volt.
Connecting track sections:
Below draft clarifies how to connect the feedback module
RM-GB-8-N to a track.
Normalgleis
Überwachte Gleisbereiche
Standard track
Monitored areas
IN1 1
s88-N
OUT
Digitalstrom von
Digitalzentraler
oder Booster
Richtung
Digital current from
Digitalzentrale
command station
Direktion to
or booster
command station
s88-N
.
s88-N
2 3 4 IN2 5 6 7 8
RM-GB-8-N
s88-N
IN
Von weiteren
Rückmeldemodulen
From further
feedback modules
Digital current will be supplied to the RM-GB-8-N via input IN1
and IN2. IN1 provides current to the output 1 to 4 and IN2
provides current to the output 5 to 8. The two inputs IN1 and IN2
are electrical separated.
Therefore will it be possible for example to supply IN1 from the
digital command station (control unit) and IN2 from a booster.
With reason to have a correct feedback report is it required to
supply digital current to both inputs (IN1 and IN2).
By using the control unit or a booster on IN1 or IN2 connect the
digital current for the supply of the continuous rail to the
clamp with the continuous white line.
Output clamps 1 to 8 shall be connected to those isolated
tracks, which shall be monitored. As indicated in the draft it is
sufficient to isolate one rail. The clamp with the dotted line
shall be connected to the rail track section to be monitored.
Detailed sample connections for various application can be
downloaded from our web-site (www.ldt-infocenter.com) within
the section "Downloads".
To avoid short circuits when locomotives are crossing the
transitions of each monitored track, always the same connecting
sequence of the tracks has to be strictly followed.
In case of a short circuit when crossing the transition (control unit
will switch to EMERGENCY STOP) please check the
connections and eventually change the cables of the monitored
track at the respective OUTPUT clamps.
Anti-interference capacitors can lead to an erroneous
we offer occupied detection of the track and should therefore not be used
within the monitored track.
If you apply electrical resistant coating to the axles of your
trains you should measure the resistance value with a Multimeter
afterwards.
A resistance between 5 and 10 KOhm will guarantee a safe
monitoring by the occupied track detection of the feedback
module RM-GB-8-N.
Customary used resistance axles with a resistance value of 18
KOhm will just be monitored, provided that the rails are very
clean and the railway coaches have a sufficient contact to the
rails. In such case it will be recommended, to fit two resistance
axles to the coach to receive a total resistance value of about 9
KOhm. This will assure a save monitoring even when the rails
are not perfect clean.
Accessory:
For easy assembly of the RM-GB-8-N-F below your model rail
road layout base plate we offer a set of assembly material under
the order identification: MON-SET. Under LDT-02 you can
purchase a low priced durable suitable case.
Trouble shooting:
What to do if something is not working as described above?
If you have purchased the RM-GB-8-N module as a kit, please
carefully check all parts and all soldered joints.
Important: Both inputs (IN1 and IN2) have to be connected to a
digital current.
Possibly test the single monitoring function of the modules first
before connecting it to the tracks.
To do this you can use a resistor (couple of hundred Ohm) or a
small model lamp to simulate the occupied situation on each
output clip.
Without resistor or incandescent lamp the detection of the input
should be indicated as "free", with a resistor or incandescent
lamp your digital control unit or PC should show an "occupied"
situation.
Littfinski DatenTechnik (LDT)
Bühler electronic GmbH
15370 Fredersdorf / Germany
Phone: +49 (0) 33439 / 867-0
Internet: www.ldt-infocenter.com
Subject to technical changes and errors. © 08/2022 by LDT
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