Roco LINE Mode D'emploi page 26

GB To this end, initially remove the protective lid from the circuit board of the
underfloor drive. As is shown in Figure 38 the small crosshead screw in the
depression of the protective lid must be loosened and completely removed
as a first step. Then introduce a flat medium-size screwdriver in the demoul-
ding openings of the mounting claws on the switch side of the protective
lid – as also shown in Figure 38 – and slightly force the claws to the outside
to separate them from the circuit board. Then tilt the protective lid down-
wards. Once this has been done the protective lid will automatically release
the circuit board on the other side and the protective lid can be completely
removed.
After this, clip on the protective lid in the correct position. When doing so
please pay attention also to the two operating mode selector switches so
that these engage correctly in the appropriate recesses of the protective
lid and are not forced down! Once the protective lid has been clipped on
correctly and the two switches are neatly seated in their respective protec-
tive lid recesses, re-insert the small crosshead screw in its depression and
finally tighten it. Please do not overtighten the screw to avoid damaging the
thread. Once everything has been down correctly please check the position
of the two operating mode selector switches and readjust in accordance
with the operating conditions for your turntable applicable to your system
if required.
Drive current polarity display
a) Basics:
Since it is necessary for the control of the radiating tracks (shed tracks,
maintenance tracks, other siding tracks and access tracks to the turntable)
that the radiating tracks are supplied with drive current from the turntable
platform, all tracks leading to the remaining system must be insulated on
both poles as shown in drawing 26. Only then is it possible for the control
of the radiating tracks from the turntable to operate correctly. Based on this
type of drive current feed however there is a risk that "hostile" polarities
will meet at the transition point formed by the insulating rail connectors of
the access track fed from the platform to the remaining system so that a
complete short circuit is created at the moment this point is passed.
Since with digital operation the actual respective polarities in the tracks
left and right of the insulating rail connectors play no role with regard to
the direction of travel of the locomotive passing that point and it merely
needs to be ensured that the polarities on both sides of the insulating rail
connectors are identical, this problem can be resolved in digital mode by
using the return loop module as already described at another point in these
instructions.
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42615 Anleitung deutsch.indd 26
In classic DC mode for which the turntable is also designed the situation is
slightly different. Here the respective polarities left and right of the insu-
lating rail connectors need not only be identical – as in digital mode – but
they also decide in which direction the locomotive will continue to operate.
We therefore have to ensure that the polarities do not only correspond
to each other but that they are also applied correctly – coming from the
turntable platform – so that our locomotive is able to continue moving in
the desired direction.
b) Practical application:
With the two-pole changeover switch depicted in drawing 26 (see arrow)
this polarity adaptation can be accomplished easily. However this does not
provide any information as to whether the polarities are really matched.
With a total of four light emitting diodes (practically two green and two
yellow) and two resistors for current limitation in the light emitting diodes
per connecting track and the remaining system it is possible to very eco-
nomically establish the monitoring circuit shown in the detail magnifier
(drawing 26a).
If the light emitting diodes are correctly installed the lighting up of both
green light emitting diodes will not only indicate that the polarities match
on both sides of the insulating rail connectors, but also that the direction
of travel so set leads from the turntable away to the rest of the system.
However if both yellow light emitting diodes light up this means that the
polarities on both sides of the insulating rail connectors match again, but
that the direction of travel now set leads away form the remaining system
to the turntable platform.
However, should a green and a yellow light emitting diode light light up
this means "imminent danger" that a locomotive will cause a complete
short circuit when passing the insulating rail connectors since the polarities
are not matched. In this case it does not matter on which side of the insula-
ting rail connectors the yellow and on which the green light emitting diode
should light up. To purely avoid the short circuit it is immaterial which of
the two light emitting diode colours happens to be "active". However the
decisive point is that the light emitting diodes with the same colour light
up on both sides of the insulating rail connectors.
For practical purposes it is advisable to install the two-pole changeover
switch and the total of four light emitting diodes (one green and one yel-
low on the left, the other green and yellow on the right) in a common box
accommodated in the vicinity of the manual control unit for the turntable.
c) Note:
 The two-pole changeover switch, the light emitting diodes and the
resistors are not part of the scope of supply of the turntable.
 This circuit cannot be used for digital operation or in a 3-conductor
alternating current system!
31.01.2011 09:18:58