Hi there
I was hoping someone who has installed one of these can assist me please.
Have installed as per manufacturers instructions on my DCC system.
http://www.heathcote-electronics.co.uk/DOT2.htm
I notice that when a loco enters the isolated section of track ( i.e. between the 2 gaps in the rail ) it stalls before even reaching the infrared light.
I'm wondering if I have missed something in the installation, particulalry with the wiring of the isolated section of track.
If you refer to the diagram in the above link, I have the "North rail" wired to my black track power bus and the "South rail" either side of the rail gaps wired to the red track power bus.
Should I have a drop feeder between the rail gaps connected to the red track power bus ??
All terminals from the IRDOT are utilised as per manufacturers instructions expect for Terminal 3.
Any idea what that is used for or is it intentionally left not utilised ?
Appreciate any advice or tips you can offer
cheers
I cannot help, but would like to make a comment. I was thinking about getting the IRDOT-1D, however I was under the impression it was all "Infrared" blocking the beam and unblocking the beam performing a switching action. According to the IRDOT-2 diagram, why are pieces of the track gapped? I am so confused.
The diagram with the gap is for an automatic stopping section, which will cut power to the train when it breaks the beam.
According to the diagram shown, if the contacts are shown in their proper operating position, it will do exactly as you have happening - the train will stop the instant it hits the isolated section. If they used proper reference in the sort-of schematic diagram, you would want to hook the isolated track section to terminal 3, not terminal 2, since the way it's drawn is that normally the relay will connect 3 and 4, and when the beam is broken will connect 4 and 2.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hi Randy
Thank you for your reply.
Looking at the web site again, it says that, with no train detected the relay connects Terminals 2 and 4. When a train is detected ( i.e. the beam is broken ) the relay connects Terminals 3 and 4.
I have wired mine as per the manufacturers web site instructions.
What you are suggesting is the exact opposite i.e. when beam is broken connects Terminal 2 and 4 and with no train detected connects Terminals 3 and 4.
I'm not doubting your comments, as I am a bit electronically inept, just confused.
Are you saying that their comments re connection and the accompanying diagrams are drawn incorrectly ?
I guess the only way is to switch connections and see what happens.
Appreciate your advice though.
Many thanks
Can you physically see the relay to get an idea which way it moves when the beam is broken? Or it it one of those opaque cased type that you cannot see the contacts? I am going by the diagram, convention in electronics is to show the relay contacts in the 'steady state' condition, which would be NO train detect, ie, the beam getting through. If the diagrams are drawn correctly, then 3 and 4 are connected normally, which yes, is opposite what you say the text instructions read. If you're worried, test it with a meter, Assuming 2,3, and 4 are the relay contacts, with 4 being the common, put your meter on ohms and test 3-4 with the beam up, and test 2-4 with the beam up. Then interrupt the beam and whatever the previous results were should reverse. Whichever ones are closed (short circuit, 0 or almost no ohms reading on the meter) when the beam is up are the ones you need to use to turnt he power on and off to that isolated rail. My feelign is that since the train stops instantly the way you ahve it wired, before the beam gets broken, it almost has to be the othe rcontact, 3 instead of 2. It certainly won't hurt anything to switch it and give it a try, worst case is the train doesn't stop when it breaks the beam. I assume that the wire you have connected from the non-isolated portion has power, ie if you have the gap in the right-hand rail, you have a live wire from before the gap connected to the relay contact, and then the feeder going to the isolated section of the right hand rail.
Hi again Randy
Firstly thank you so much to taking the time, and patience, to assist me in getting this IRDOT woking properly.
I have mine wired exactly as per the diagram on the heathcote web site i.e. the diagram with the isolated track.
There is non-isolated track either side of the isolated portion.
If you refer back to the diagram for a moment, I have power going to the "right-hand" part of the track, just before the gap.
The "left-hand" part of the track ( i.e. the non-isolated portion that is connected to Terminal 4) has no track power from my main power bus.
Is that where my problem is ?
I'm thinking that Terminal 4 is common no matter which way T2 and T3 are connected to the IRDOT.
Based on the way I have the unit connected, I can see that when there is no train on the track T2 and T4 are connected as in a simple on-off switch. T2 and T4 being "on". When the beam is broken, then the power is turned "off" i.e. T3 and T4 are connected.
If I have no track power on that portion of non-isolated track to the left of the T4 connection, then how can power possibly be connected to the unit via T4 to enable the "on" and "off" scenario ??
I hope I have explained myself and read things properly.
As I said, electronically inept I am !!!
cheers and thank you again
Just thought I should add an important point ( I believe ).
The track in question is in a staging yard and therefore is "stub-end" on the portion of track that connects to T4.
Upon reflection, and again this is from a complete electronics novice, this is where my problem is. No track power past the connection to T4.
I guess that could be solved by re-routing the track power drop feeder to the right of the unit ( just before the rail gap ) direct into T4 ??
update:
Problem solved !!
It was as I suspected as per above. Once I connected power to the track past the Terminal 4 connection ( the far left-hand portion of track in the diagram) the unit works perfectly.
Thank you Randy for helping me think this issue out for myself.
Some satisfaction for me being a novice at electrical issues. Your answers got me thinking this out for myself.
Greatly appreciated and sorry to waste your time.
By the way, the IRDOT works perfectly in the staging yard which is in a seperate room to the layout and I would highly recommend this product to those in similar situations.
Thanks again
Glad to hear you got it fixed. I don't consider my time wasted - you learned something and fixed it yourself. You'll probably remember the issue better too, since you figured it out after getting a little nudge rather than me or someone else just telling you the answer.
Just remember to have it in reverse before hitting the bypass pushbutton Or have a strong bumper.