Can a crest 5475 be made to actuate solenoids ?

maxi-model

maxi-model

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Ok, silly question/wishful thinking. Can a Crest 5475 actuate a solenoid ? Yes, I understand the 5475 accessory controller is in effect a mometary switch, with 5 individual channels, and works fine with multiple LGB point "motors" but not with a solenoid. As I understand it the solenoids in question, made for the SSVR pneumatic point switch system, need 12v at 1 amp to open (which the 5475 can do) + 0.1 watt continuous current (which the 5475 does not) to hold the solenoid and air valve they actuate open. Remove that 0.1 watt current and the solenoid and air valve close. So is what is needed a "latching" type switch instead ?

So the question is - Is there something that can be interposed between each of the 5475's 5 outputs and the solenoids to be actuated (5) that can be switched on/off by the momentary current from the 5475 to provide the .1 watt "latching" current to hold the solenoid open?

Sorry if this all sounds a bit daft, and if my understanding of the terminology is a bit off kilter, but I'm sure the electronic experts here will get the drift. If it can't be done it can't be done and will have to wait till I make a change to my layout's overall control system. Your inputs would be most welcome. Max
 
JimmyB

JimmyB

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Max, my understanding seems to be similar to yours, however surely not all solenoids need to be held open, I recall the peco solenoid point motors just needed current to switch.
 
maxi-model

maxi-model

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Max, my understanding seems to be similar to yours, however surely not all solenoids need to be held open, I recall the peco solenoid point motors just needed current to switch.
I've spoken to Simon Whenmouth at ANG and he has spoken to Pete at SSRV and they say the SSVR supplied solenoids need a continuous 0.1 watt current to hold the solenoid open. Each pneumatic piston, attached to a point to move its blades, needs the air valve controlling it held open to keep the point blades in position. Cut off the current to hold the solenoid open and the piston and attached spring loaded point blades snap back to whatever the default closed valve position is. You can see the problem with a momentary switch with these.

The thing is the air valve and solenoid are one unit so it would need an alternative type of air valve unit that can be operated by a momentary switch - i.e. One pulse the valve opens and stays open, another pulse and the valve closes. It would either have to be threaded to be compatible with the SSVR manifolds or come with its own to be mounted on that can use the SSVR's 1.6 mm ID tubing (although it could be sleeved to match) Nice thought though. Max
 
Greg Elmassian

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You do need continuous current, (and also snubbing diodes across the solenoid coil).

You would have to design a "flip flop" type of circuit to latch, trigger, latches on, trigger again, latches off.

no mechanical latching of the air valve sorry!

You might go to the Clippard site (where SVRR gets their components) and see if there is a cheap solution, but I doubt it.

so the outputs are reversing in polarity (while momentary)


If I had to do this simply, I would get a latching relay, with the "set" / "reset" capability, set those 2 triggers up to run "set" as a positive pulse, and "reset" as a negative pulse, and there you have it. This way the relay also handles the inrush of the solenoid coil, and lastly you can run the 5474 at an optimal voltage (usually a nice regulated 12v) and the solenoids at whatever voltage suits you.

Be sure to read George's page.

Greg
 
maxi-model

maxi-model

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Thank you Greg. Very informative, if only I could understand a word of it :) As you may have noticed I am someone who even finds "plug and play" confusing :D But at least there may be a solution. If not I'll stick with the manual operation. It's just a "would be nice" and I have the bits lying around from my days using LGB point motors. I shall most certainly take a look at George's pages. I think they were the first I bookmarked, many years ago, when I got into this hobby. Problem is I keep on forgetting to reference them, so thanks for the reminder. Max
 
Greg Elmassian

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I'd be happy to take it on here as a project, should be pretty simple.

The relays should be relatively inexpensive. I love my pneumatic switches.

Also, I have read George's site "cover to cover" 5 times.

Greg
 
The Tinker

The Tinker

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What about using a HO point motor to operate a simple on/off contact switch HO point motors are cheap and contact switch could be homemade with brass and solder. The Crest 5475 should be able to operate HO points motors.
 
maxi-model

maxi-model

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$2.14 each.....

Pretty simple, wire directly to Crest unit.

Greg
That looks an interesting device Greg. What does it do ? So, i assume you will need as many as there are outputs on the 5475 ? They will be taking an input (12v 1 amp, voltage regulator required ?) from the 5475 to activate them (5) in some way ? Are they generating the 0.1 watt in some way to hold open the solenoid and if so what is their power source ? Sorry if I am coming across as very dumb. Max
 
Greg Elmassian

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Looks like there are dual units too.

they are relays, so no problem with current.

they make a 12v version...

the data sheet shows the contact ratings, over an amp and way over 12 volts... so the contacts can handle the solenoid...

the coils will work down to 9 volts... I would regulate the power supply, 12v supplies are cheap, and the Aristo units benefit from a stable voltage...

pulse the set terminal with 9 to 12 volts, the relay latches "on", pulse the other terminal, it latches off. The only fly in the ointment I see is that the 5474 may be putting out reverse voltage... will have to think on it, or perhaps find a different latching relay... there are tons of these out there.

Greg
 
maxi-model

maxi-model

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Looks like there are dual units too.

they are relays, so no problem with current.

they make a 12v version...

the data sheet shows the contact ratings, over an amp and way over 12 volts... so the contacts can handle the solenoid...

the coils will work down to 9 volts... I would regulate the power supply, 12v supplies are cheap, and the Aristo units benefit from a stable voltage...

pulse the set terminal with 9 to 12 volts, the relay latches "on", pulse the other terminal, it latches off. The only fly in the ointment I see is that the 5474 may be putting out reverse voltage... will have to think on it, or perhaps find a different latching relay... there are tons of these out there.

Greg
It would help if I could understand what the actual function is those little devices are performing between the 5475 and the solenoids Greg. I rely on your undoubted knowledge and experience in these things, as always :) Max
 
Greg Elmassian

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they are latching relays. a normal relay closes and opens contacts when energized

a latching relay closes when pulsed on one input and releases when pulsed on another input, i.e latches in place

this effectively creates the short term pulses from the 5474 to constant on or off states...

there is a circuit diagram and explanation on the pdf file I linked
 
maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
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Bucks/Oxon/Northants area
they are latching relays. a normal relay closes and opens contacts when energized

a latching relay closes when pulsed on one input and releases when pulsed on another input, i.e latches in place

this effectively creates the short term pulses from the 5474 to constant on or off states...

there is a circuit diagram and explanation on the pdf file I linked
Thank you Greg. Must be off to work now, it's 9 am here :) Max
 
Greg Elmassian

Greg Elmassian

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Here's a video explaining latching relays.... I am sure we can find ones that connect directly to the 5474, and in turn can drive an air solenoid.


Greg
 
D

Dan

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Aristo 5474 and 5475 have dc to dc converters inside and put out at least 16 volts even when the input is 6 volts.
The 5474 does have the C output with a latch and can drive a 18 volt LGB bulb, and D and E are open collector drivers which were used to activate bell and/or whistle sounds.
Geroge Schreyer's guide has a lot of info on these units.
 
Fred2179G

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I added a 5475 to my 2-8-0 and found the contacts were rated too low to switch in the Aristo sound board! So I bought some reed relays from Radio Shack and wired them on a separate board to handle the higher-current. Two of the 5475 outputs are actually latching (they stay on after you press the TX button) and they worked fine with my reed relays. You can buy a reed relay in any size you like, as long as it draws very little current itself.
The attached pic shows the stuff inside the 2-8-0 boiler: mini-recvr, accessory board, and on top the small pcb with the reed relays.
 

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John S

John S

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So the question is - Is there something that can be interposed between each of the 5475's 5 outputs and the solenoids to be actuated (5) that can be switched on/off by the momentary current from the 5475 to provide the .1 watt "latching" current to hold the solenoid open?
132648_970a45147ee71d1a43a4ae841ffaca40.png
 
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Greg Elmassian

Greg Elmassian

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I chose an off the shelf latching relay to keep it simple as I had the impression that Max wanted simple. Also, doesn't your circuit depend on a break before make situation on the outputs? (which is probably true)... but it's not deterministic, i.e. changing the state toggles the output, but does not set that positive voltage to be on in the solenoid, since it appears your bridge changes the positive and negative pulses to just a series of positive pulses.

Perhaps I misunderstand...

Greg
 
Greg Elmassian

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yep, and should only require a couple of diodes, since you want to run both coils from the same 2 output wires on the Crest unit.

But of course it is about 4 times the cost of the unit I found earlier.

Greg