Re: Lenz LB101 Occupancy Detector and Switches

Robert Prondzinski <bobprond@...>

Thank you very much for responding. You have been the only one that has answered my query. I am very light in my understanding of electronics, what I do have some basic understanding. I would appreciate it if you would send me a diagram.
I thought as new DCC user that the situation I posed was relatively common for people to want to do. Unfortunately I have just got started with understanding one occupancy detectors can and cannot do. Thank you again

----- Original Message -----
From: Vollrath, Don
To: WiringForDCC@...
Sent: Wednesday, May 18, 2005 9:39 AM
Subject: RE: [WiringForDCC] Lenz LB101 Occupancy Detector and Switches

Yes...But you don't really need those occupancy detectors to control the turnout. All you need is an isulated balloon track loop, an auto-reverser, and a short constant polarity track length approaching the frog ends of the switch. (Somewhat equivalent to your Case 2 but shorter sections for A & B, and greater-than-train length for the actual reversing loop C.) Now see Look at the dwg for signaling the polarity status of a Reversing track section with a 3-wire bi-color LED. It works by detecting which rail is at the correct polarity for a Green signal. Now in your mind replace ONE of the LEDs with a DC relay coil, where the contacts of said relay control the switch machine. A train enters the loop (section A) in the direction last established...Assume that the polarity of reversing track (C) will be correct. Nothing will change until the train nears the exit end of the loop and crosses the gaps between C and B. At that point the A-R unit sees a polarity mis-match and flips the polarity of track C. This act (and the steering diode) energizes (or de-energizes) the relay coil. Relay contacts change connections to the Tortoise (or other) switch machine and correct turnout position for exit.

Constant polarity Entry-Exit tracks (your A & B) need to be only long enough for the switch machine to throw the turnout before the train reaches the point rails (or energized frog).

Add a free-wheeling diode across the relay coil. When energized, the relay coil will see 1/2 the DCC track voltage and be constanly ON. For HO scale use a 5Vdc relay with resistor in series (like the LED circuit) to adjust coil voltage and prevent overheating. resistor value will be relay choice dependant.

The LK100 (and some other auto-reversers) does draw a noticable amount of current. So will the added relay coil. If wish to use an occupancy detector be sure to place it directly on wires going to the track so that it does not see current consumed by the LK100 or the turnout control relay.

Too complicated? I can send you a diagram if you need it.


-----Original Message-----
From: WiringForDCC@...
[mailto:WiringForDCC@...]On Behalf Of bobprond
Sent: Tuesday, May 17, 2005 10:49 PM
To: WiringForDCC@...
Subject: [WiringForDCC] Lenz LB101 Occupancy Detector and Switches

I have never used a block occupancy detector before and therefore
ignorant in its operation. I have a reverse loop working well
using a Lenz LK100 Reverse Loop Module. I now want to integrate
occupancy detectors within that loop to switch the Y-turnout
controlling the loop (See Case 1 & 2).

Is it possible, WITHOUT USING SOFTWARE, to toggle a switch
automatically using a Lenz LB101 Occupancy Detector. Is there any
other item I would need to make this happen? Would Atlas Snap
switches be of any help? How would this be wired?

Reverse Loop Case 1 (Two Sections):

Is there anyway to automatically toggle a Y-switch in a reverse loop
depending upon whether a train is located within one half of the
loop or the other. I have a reverse loop using a Y-switch. The
loop itself is divided into 2 equal 80 in. sections connected with
insulated joiners. I am not planning to run trains on the loop > 60
in. I can put a Lenz Occupancy Detector on my power drops on
each of the two 80 in. loop sections. When a train enters the loop
in one 80 in. section and crosses over to the other 80 in. section I
would like to I would like to automatically toggle the Y-switch to
the opposite position, therefore having the train exit the reverse
without manual intervention. Can this be done?

Reverse Loop Case 2 (Three Sections):

I have an 170 in. reverse loop divided into three sections. The two
sections entering/exiting are each 80 in. long (section A & B).
These two sections and the farthest point in the loop are connected
to a 10 in. piece of track (section C) using insulated joiners. I
have power drops in all three sections. If I put the Lenz Occupancy
Detector in section C, can I automatically toggle the Y-switch to
its opposite direction. I am not going to be running any trains
through this reverse loop > 60 in. Ultimately, I want to have a
enter a Reverse Loop, in section A or B, passover section C which
has the Occupancy Detector which then toggles my Y-switch
allowing exit of the loop without any human intervention. Is this

Equipment I have:

Lenz LK100 Reverse Loop Module
Lenz LB101 Occupany Detector
Lenz LR101 Feedback Module
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