Where to get and how to use a Relay that Counts the laps a train makes

[Anonymous]

QUOTE: Originally posted by FJ and G



or, you can attach a string to a crossing gate that attaches to a weight that drops down to a calculator that adds one with each closing of the gate as the train goes round and round

I might just have to try that!!!

[FJ and G]

one other way this counting could be done is to run the trains via computer and design a simple 1+1 loop in BASIC

[Anonymous]

Thanks Bob, that sounds like the same concept that the depotronics circuit uses except without the e-unit and is probably alot cheaper than the 125.00 for the actual circuit.

[lionelsoni]

Well, if you or anyone else might still want to try it with relays, I have been able to get the relays down to two poles each:

All three relay coils are wired the same. In series are the supply voltage, a resistor, the relay coil, a normally-open contact on the same relay, and ground. The supply voltage is twice the relays' operating voltage. The resistors' resistance is the same as the coil resistance and their power rating is such that they can safely handle the full supply voltage indefinitely. Each of these relay circuits can be turned on by momentarily grounding the end of the coil connected to the normally-open contact and turned off by grounding the end of the coil connected to the resistor.

First the simpler problem of just alternating running of the two trains. One relay is designated the "master". It records which train has just arrived. The master is controlled by two isolated running rails, or "control" rails, at the arrival ends of the two siding tracks. The control rail on the main line turns the master on; the control rail on the siding turns it off.

Another relay circuit is designated the "slave". It copies the state of the master, but not immediately. One of the slave's single-pole-double-throw contact sets switches track voltage between the center rails of the two tracks of the siding. It powers the main when the slave is off and the siding when it is on. Another pair of control rails near the departure end turns it on and off, much like the master. However, a normally open contact on the master is in series with the control rail on the siding, that turns the slave off.

To throw the track switches, the two switches are wired together, in parallel. The anti-derailing feature automatically insures that, when a train departs, both the arrival and departure switches will be aligned to let it back into the same track. If the switches don't have that feature, you can provide it easily with another pair of control rails at the departure end.

The third relay circuit and the e-unit count the laps. The relay circuit is turned on by a control rail somewhere on the main-line track between the switches and off by another control rail far enough away on the layout that both are not occupied at once. Thus it switches on when the main-line train arrives and off after it departs. A normally-open contact on that relay operates the coil of the e-unit. The e-unit contacts are isolated by cutting the connection to the supply terminal on its circuit board. Two of the wires, for example, green and yellow, will provide a contact that is closed every four steps. This contact is wired in series with the control rail described first above at the departure end of the main-line track, so that the main-line train must pass 4 times before it can switch power to the siding train.

Notice that the relays and the e-unit's power supplies might need to be different, depending on the specifications of the relays that you use. You could dispense with the third relay and just operate the e-unit directly from a control rail; but contact to the control rail might be intermittent and cause the e-unit to count erratically. The relay circuit prevents this.

For Depotronics, see http://www.depotronics.com/

I have edited this to fix a few errors (and probably will again).

[Anonymous]

I actually found the CTT issue that mentioned what I wanted to do. It is the May 1999 issue about their Desert Layout. The part I need is a Depotronics Watchman Micro I Circuit board . Whatever that is. Thanks for the ideas.

[FJ and G]

If you are using DCS, you can calculate the scale miles run and the scale miles of track that make the loop.

or, you can attach a string to a crossing gate that attaches to a weight that drops down to a calculator that adds one with each closing of the gate as the train goes round and round

[lionelsoni]

RJ, here is a way to do what you want. I had hoped it would be simpler. Perhaps someone else here can improve on it. It uses 3 relays and an e-unit.

All three relay coils are wired the same. In series are the supply voltage, a resistor, the relay coil, a normally-open contact on the same relay, and ground. The supply voltage is twice the relays' operating voltage. The resistors' resistance is the same as the coil resistance and their power rating is such that they can safely handle the full supply voltage indefinitely. Each of these relay circuits can be turned on by momentarily grounding the end of the coil connected to the normally-open contact and turned off by grounding the end of the coil connected to the resistor.

First the simpler problem of just alternating running of the two trains. One relay is designated the "master". One of its single-pole-double-throw (SPDT, or form-C) contact sets switches track voltage between the center rails of the two tracks of the siding. (I suggest that the main be powered when the master is off and the siding when it is on.) The master is controlled by two isolated running rails, or "control" rails, near the departure ends of the two siding tracks. Each control rail switches the master to the state that powers the opposite track.

Another relay circuit is designated the "slave". It copies the state of the master, but not immediately. Another control rail far from the sidings grounds the common of another SPDT contact set on the master, which routes the ground to the side of the coil of the slave that causes it to switch to match the master. The purpose of the slave is to remember the former state of the master even after the master has been switched by the control rails on the siding tracks. A normally-open contact from the slave is in series with one of those control rails and a normally-closed contact is in series with the other control rail, so that only the control rail from the track on which a train is arriving can switch the master. The slave's contacts keep the other, already-arrived train from immediately trying to switch back.

All that is missing is the track-switch throwing. That is easy. The two switches are wired together, in parallel. The anti-derailing feature automatically insures that, when a train departs, both the arrival and departure switches will be aligned to let it back into the same track. If the switches don't have that feature, you can provide it easily with another pair of control tracks. (You don't need it at the arrival end, but having it there doesn't hurt anything.)

Now, adding on the lap counting is easy. The third relay circuit is turned on by a control rail near the arrival end of the main-line track and off by another control rail beyond the departure switch. Thus it switches on when the main-line train arrives and off when it departs. A normally-open contact on that relay operates the coil of the e-unit. The e-unit contacts are isolated by cutting the connection to the supply terminal on its circuit board. Two of the wires, for example, green and yellow, will provide a contact that is closed every four steps. This contact is wired in series with the control rail described first above at the departure end of the main-line track, so that the main-line train must pass 4 times before it can switch power to the siding train.

Notice that the relays and the e-unit's power supplies might need to be different, depending on the specifications of the relays that you use. Also, the first two relay circuits need three poles. If you can't find suitable three-pole relays, you might have to fake it with, for example, a two-pole relay driving another two-pole relay.

[Big_Boy_4005]

QUOTE: Originally posted by Charlie Bee

Sounds like the job of the engineer. What happened to your engineer?

Charlie

Charlie, automation is a really cool concept for people who just want to sit back and watch their trains go around. I have done a lot of it in the past, and it is way more fun than simple circles. It can be a real challenge to get it right, but once you do, there is a great sense of accomplishment.

My new layout will feature computer controlled automation on the mainlines, allowing either the computer or a human operator to run the trains.

[Anonymous]

Sounds like the job of the engineer. What happened to your engineer?

Charlie

[Big_Boy_4005]

I have an idea on how it can be done with relays, though it will take a few. You could use the relays to count the laps. Each lap a relay is "latched", when the last relay is latched, it stops the first train, starts the second train, and releases all of the relays, so the process can begin again.

This is a little complicated, and I'm sure there are easier ways, but my question is why count laps? There are a lot of interesting things that can be done with relay logic and automation.

[eZAK]

Your best bet would be to contact http://www.digikey.com/ or http://www.allelectronics.com/index.html

I don't know if you could get a counter to do that or not.
It would have to have a settable trip and a set of contacts.

One thing you could try is a timer relay in conjuuntion with a 153 IR controler.
Set the 153 IR up on your layout to trip the timer which would be set for however long it takes to make 5 laps.

Another idea would be to try http://z-stuff.net/ they have a few different stop start modules.

[Anonymous]

I want to have two trains run on same track ,which I know how to do. But I wanted to expand this concept by having a train sit in a siding while the other train makes 3 to 5 laps. After the 5th lap, I want this train to release the parked train to make a lap and then return to its siding and start the mainline train again. I remeber reading an article in CTT where they briefly talked about using a lap counter on a desert layout but they didn't get into great depth on the subject. Any help would be greatly appreciated.