Think I’m going to abandon the IR sensors and go back to Isolated track wiring. Now here is the question;
Have two different tracks running in parallel, each track is on a different “Throttle” Control of the New ZW xfmr. So, if ran a wire between each of the isolated inside rail sections, then to the signal wouldn’t be a problem. (Since the “common or ground” is at the same potential for both Throttle Controls.) Now the intent is to have the signal power from an Auxillary old ZW, and the ground of course is NOT at the “same” potential. This could be a problem.
So I “guess” the best answer is to use a relay to be powered from the track potential, and complete the signal circuit thru its contacts? Or, am I making this too complicated?
(Essentially their would be 4 isolated track sections that would activate the relay, two tracks, activated from two different directions each.)
Furthermore, since 1 track is Track A, the other Track B, providing “Power” to the relay brings up a question, if the relay is powered from the track, then the + from both tracks would be needed to connect to the + of the relay. Now this would cause for the two tracks to be shorted together, thru the + connection at the relay. Seems NOW that 2 relays are required?
I believe the hot from transformer goes to the relay it’s the common that goes from the isolated rail to the relay that completes the circuit which changes the contacts to show red\green light. dallee has a 12 volt relay and seems like another manufacturer does too. I believe you can use one relay and wire it to show both red lights on at same time and so on. if you want real aspect showing of signals I’m sure there’s a way just a lot more wiring and I’m sure someome better versed than I can give you help maybe even a schematic to use.
You wrote, “Now the intent is to have the signal power from an Auxillary old ZW, and the ground of course is NOT at the “same” potential.” Why not? Is there some special reason why you can’t connect the old ZW’s U terminal to the outside rails?
I don’t understand why the U from each transformer can’t be at the same potential. Something to do with the new ZW perhaps.
Anyhow, two relays would be required to do what you’re talking about, just as you suspected. Here’s a very rough sketch of how it could be wired to work:
For what it’s worth, I use relays made by a company called Functional Devices called “Relay in a Box”. These are marketed toward heating and air companies, so perhaps a local supply house might stock them. They’re nice because they have a voltage regulator circuit built into them, which means they don’t chatter during under voltage conditions, and the coils are rated to 24v (ac or dc IIRC).
I see no reason to use relays. Connect the accessory transformer’s U to the outside rails of the track. Connect the accessory transformer’s A, B, C, or D to one terminal of the crossing gate or signal. Connect the other terminal of the crossing gate or signal to both insulated rails. If you like, plug the accessory transformer in so that it is out of phase with the track transformer(s), so that its return current will partially cancel rather than augment the return current from the train.
The HVAC industry is a good source of inexpensive 24-volt AC relays, for those who need them. For example, here is a Steveco 90-293Q relay on Amazon for $8.79: http://www.amazon.com/Steveco-90-293Q-SPDT-Relay-COIL/dp/B0015XK0TM They are also a good source for 24-volt transformers and multi-conductor thermostat cable.
DC relays are probably the most practical for toy trains. There is no reason not to operate relays from track circuits, using a DC supply. Radio Shack carries a number of 12-volt DC relays.
Thank you very much for your comments. Regarding the ground/common of the track transformer and the accessory xfmr. - I have been very careful no to mix the circuits and make sure the grounds were independent of each other. The reason is I have DCS, TMCC, & Legacy running, I didn’t want to "confuse the issues with multiple transformers on the track possibly affecting command control. It it necessary? I don’t know, I just thought that the 2 transformers may have some minor differences that could impose a problem. Also the new ZW may have more current limiting characteristiics and with all the other overkill I’ve done to try and protect the eqiupment. (TVS’s, Ckt Brkrs, Fuses) I didn’t want to do something stupid and induce a voltage from another source. Trying to error on the conservative side.
I have some relays I can use so going with the ckt as drawn by JW above.
Just wondering here… why are you abandoning IR sensors? I see advanatges to isolated track but can see advantages to the IR’s in certain applications too. Thanks.
I have the Lionel sensors, there may be some others that are more reliable. Here are my issues;
They are sensitive to ambient light, if I adjust the sensitivity in the daytime, they are very erractic at night. Also relative to the amount of ambient daytime light that is available, morning different than afternoon or different in the evening. All affects the responsiveness. So try and pick the “optimum” operation.
Also, sensitive to the “color” of the car that is crossing. Light colors OK, coal hoppers will not be picked up or detected. The engine type or color is also erratic. Steam engines work better than the diesels, I am assumng due to the connecting rods. If I have a light colored diesel go buy it will pick up, if it is maroon or darker it will not.
The duration of activiation is based up the “timing/delay” adjustment. If I have a device located in between two sensors and adjust the time so that when the last car of a 4 or 5 car consist has enough delay to permit the last car pass the device, then when it crosses the path of the sensor for a train coming from the opposite direction, the device is activated again. The train “long gone”, and the delay makes it worse.
By simple track wiring all these problems are eliminated, and the cost is insignificant compared to the sensor.
Thanks Don. I can see items #1 and #2 and the cost being a concern. The Z-Stuff dwarf IR signals I am familar with do not seem to be bothered like you describe. I am not controlling devices yet but I’m not sure how an isolated track to replace the IF sensor would quite solve the problem in #3. Won’t you still have this unwanted operation by a train running in the opposite direction? Almost sounds like having the isolated tracks closer to the device would be needed. Or maybe more isolated tracks to control the same device?.. or am I talking out of both sides of my mouth? Thanks.
The ends of the control rail would be at the same distance from the crossing as the IR sensors would be, so that the signal would operate when the approaching train is at the same distance from the crossing. With the control rail, the signal would stop when the last car of the departing train was at that same distance from the crossing. But, with the IR sensors, it would continue after that for some time.
Okay, I see the issues. I think the way Z-Stuff addresses the problem is to have an additional IR sensor. This unit is mounted right on their crossing signals. So before the first dwarf times out the train is picked up at the crossing signal itself, then before the crossing signal times out the train is picked up by the second dwarf. This would work okay in the opposite direction too. But it does require more IR sensors and maybe a minimum train length or careful adjustment of the delays; all of which the control rail does not require.
Crossing Gates and lights installed. (1 more left to do.) Wired them in using isolated track segments and a 12vdc, relay. Everything went in pretty easy, after I drew out a schmatic, and made a wire list. The most difficult part was gaining access to the track.
Think I will use the sensors for an accessory or something. I have this sound board that came with a recording “Hey Help! Get me outta here! I’m locked in this boxcar !” So can put that on a siding, probably put a toggle switch in series to turn it off when not desirable.
