Using latching relays in a control panel ??

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Flashbang
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Re: Using latching relays in a control panel ??

Postby Flashbang » Mon May 04, 2020 8:28 pm

Hi

Suzie is correct re resistors one per LED is needed. My error, copying and pasting the two wire method then altering the pasted copy without double checking! That drawing has been deleted.
Corrected drawing attached here.

D & E doesn't matter, its an example, if you want positive on D and negative on E then so be it. It really depends on which way around the Seeps are mounted and how you want the indications to illuminate. The drawing as supplied below will work. With the Seep making connection F to E the green LED will illuminate. When the Seep moves over F to D makes and the other LED will light, Simples!!

Increase resistors Ohm value to dim... Use up to 5K or 10K but is of course dependent on supply voltage.

Surprised somewhat that you are asking these basic questions? As you often are noted to be answering other peoples wiring questions. Hope you're not taking the whatsit?? :o

LED indications wire wire - Seep PM.jpg
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Re: Using latching relays in a control panel ??

Postby fourtytwo » Mon May 04, 2020 8:36 pm

Flashbang wrote:Hi

Suzie is correct re resistors one per LED is ideally needed. My error copying and pasting the two wire method then altering the pasted copy without double checking! That drawing has been deleted.
Corrected drawing attached here.

Surprised somewhat that you are asking these basic questions? As you often are noted to be answering other peoples wiring questions. Hope you're not taking the whatsit?? :o

LED indications wire wire - Seep PM.jpg


I don't wish to tread on any toes and I may be the person referred to I am not sure BUT there is no means in this circuit to limit the reverse voltage the LED's are exposed to, as I have pointed out there lifetime is a matter of conjecture without some protection. Depending upon where they are sourced from and the phase of the moon when they were fabbed it could be anywhere from nothing to years......user beware! The solution is an inverse diode across each LED.
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Re: Using latching relays in a control panel ??

Postby Flashbang » Mon May 04, 2020 8:40 pm

What are the LEDs and the resistors doing?? Each Led is inverse to the other! The same as a twin LEDs in one package. AKA Bi LEDs
You're not the person.
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Re: Using latching relays in a control panel ??

Postby End2end » Mon May 04, 2020 8:42 pm

Flashbang wrote:Hope you're not taking the whatsit?? :o

Not at all Flashbang. Living with a brain injury sometimes things just don't 'click' as it were. :wink:
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Re: Using latching relays in a control panel ??

Postby Flashbang » Mon May 04, 2020 8:47 pm

Please don't part quote. Use the whole text if need be. :D

Time to pack this one in I feel!
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Re: Using latching relays in a control panel ??

Postby fourtytwo » Mon May 04, 2020 8:53 pm

Flashbang wrote:What are the LEDs and the resistors doing?? Each Led is inverse to the other! The same as a twin LEDs in one package. AKA Bi LEDs
You're not the person.

OMG NOOOOOOOOOOOOOO I AM SOOOOOOOOOOO SORRY I just did not study the diagram enough!!
The unlit LED has the SAME voltage both ends so of course it's reverse rating is not exceeded, I must admit I could not understand why Suzies had survived given in my imagination the unlit one had -12V across it!!

Please forgive me I should never have interfered with this thread in the 1st place, I make no excuse other than old codger disease!!
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Re: Using latching relays in a control panel ??

Postby End2end » Mon May 04, 2020 8:58 pm

Don't worry fourtytwo. That's the good thing about this forum. We ALL learn. :)

OK studying the new diagram (Thanks again Flashbang ;) ) I see the 2 resistors connected where they need to be in the circuit.

I will change over the D and E wires just to keep continuity with my plans and change the wiring colours to my wiring scheme.
As you can see here on the scheme the actual F wire will be white, D - red and E green
ST Blazeys FULL Wiring Colour SchemeSM.JPG
ST Blazeys FULL Wiring Colour SchemeSM.JPG (63.29 KiB) Viewed 446 times


I will try to design a diagram with both the indication wiring and the PM1 control wiring.
It might take me a while but I'll post it when I have finished it.
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Re: Using latching relays in a control panel ??

Postby Ironduke » Mon May 04, 2020 10:37 pm

I drew this yesterday but I ran out of time
suzieppi.png
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Suzie
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Re: Using latching relays in a control panel ??

Postby Suzie » Mon May 04, 2020 11:34 pm

fourtytwo wrote:Unfortunately apart from the flaw pointed out by Suzie that would cause a dead short across the power rails through the LEDs resulting in there destruction, the reverse voltage rating of LED's is typically a mere 5V meaning in this application the survival of the unlit LED is a matter of chance rather than certainty!


The LEDs in this instance are being used only in the forward direction so as long as the power supply is DC they will be fine.

fourtytwo wrote:It is a good idea but needs some more components to make it work reliably such as an inverse IN4148 or similar low current diode connected across each LED in addition to Suzie's resistor per LED to prevent PSU shorts.


I have used bipolar (AC) LEDs with the DCC track power as power supply to save having to fit the inverse parallel diodes in an AC situation.

fourtytwo wrote:Thinking about it the original circuit would work with incandescent lamps, but not LEDs


Incandescent bulbs have their own effective internal resistor so the resistors would need to be eliminated altogether to make it work.

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Re: Using latching relays in a control panel ??

Postby Suzie » Mon May 04, 2020 11:41 pm

End2end wrote:...E and D - For indication connected to their own dedicated 12v bus run around underneath the layout...

End2ned


No need for a dedicated power supply bus, use what you already have available on the layout.

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Re: Using latching relays in a control panel ??

Postby End2end » Tue May 05, 2020 3:27 am

OK I think I've worked it out.
The diagram shows a single point with indication and a pair of points switched by a single switch with indication.
Does this look correct?
NewWiringDiagramWithIndicators.jpg

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Re: Using latching relays in a control panel ??

Postby Suzie » Tue May 05, 2020 7:38 am

Looks excellent to me.

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Re: Using latching relays in a control panel ??

Postby End2end » Tue May 05, 2020 2:44 pm

Something I completely overlooked (forgot) in my plans and diagram is my 5 x Gaugemaster GMC-PM20 surface mount point motors. :oops:
These only have 3 wires. Can point position identification using these too?
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Re: Using latching relays in a control panel ??

Postby Flashbang » Tue May 05, 2020 5:32 pm

End2end wrote:Something I completely overlooked (forgot) in my plans and diagram is my 5 x Gaugemaster GMC-PM20 surface mount point motors. :oops:
These only have 3 wires. Can point position identification using these too?
Thanks
End2end

No, not the way as per the drawings. You can of course use a PPI but that only proves the switch has moved. There is no built in change-over contacts on a PM20 or any other make of surface motor such as the Peco PL11 or Hornby R8243. You can use a latching relay to prove a pulse has been sent to the motor. Or fit a micro switch next to the point so as the micro switches lever is operated by the points moving tie bar. Another alternative is to modify a Peco PL13 switch so as it can be bonded to the points underside and a pin (small nail?) passes down through the stretcher bars hole into the PL13.
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Re: Using latching relays in a control panel ??

Postby End2end » Tue May 05, 2020 7:51 pm

Thanks Suzie and Flashbang. :)
I'm going to mull this over about whether to have indication on those 5 surface mount point motors or not and if so how to implement it.
The easy way (PPI4-DC board) or more complex ways described.
Thanks
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