# Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?



## Brandon (Jul 6, 2011)

*Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

I've been reading up on pneumatic switches for a couple months and as I'll be controlling my layout from a PC (writing some OSS software for an AI railway). There are some good choices for pneumatics to control a switch but an area I haven't seen anyone really comment on are electric valves to control pneumatic lines. There was one I saw on Sunset Valley's store but there was no information/comments on them for review elsewhere. From what I can tell most everyone who did pneumatic simply used toggle switches, no electronics at all. There are few people who did airwire to control the pneumatic DC valces but no reviews or posts about how well they have done over time. 

The question I can't seen to find is if it's worth the hassle? Are DC pneumatic valves prone to fail over the years just like typical electrical solenoid or 'better' quality servo switches do? Pneumatics without electronics are almost hassle free over many years compared to electric solenoid switches we've had in the past but if I were to put electric pneumatic valves into the equation does that put me back near the final reliability point of non pneumatic and at a higher price with more complexity of the system (and thus higher chance of parts to fail somewhere)


Also I can't find comments about newer servo and 'better' quality switches from train-li, masterline or prodrive to see how reliable they are after years of being outside. 


So I guess what I'm asking, are newer electric/servo switch machines likely to be nearly as reliable as a pneumatic system that has to use electric valves?


I keep watching the price of RC airplane servo's drop further and further I wonder if anyone has just given up with the idea of switch machines lasting 10-50 years and resigned to buying $10 waterproof servo's and just swapping out the cheap part when one goes bad. That would make computer control quite easy with one of those as a 16 port usb servo controller is $40. Only question would be how long the wires for pwm/servo control can be...


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## Greg Elmassian (Jan 3, 2008)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

No problem with mine, running DC solenoids from DCC switch machine controllers. Not one failure. 

I feel that in the weather, the pneumatic systems are absolutely the most reliable... they are completely unaffected by moisture from my experience. 


*http://www.elmassian.com/trains-mai...inmenu-101*

Greg


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## JPCaputo (Jul 26, 2009)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

For the frequency the Pwm frequency the cable can be extended around 10 ft or so. What you may have trouble with is the current needed to for the motor. 

One way I know can go long distances with little to no signal loss, use rf antenna cable for the long signal runs. Along with a pos voltage cable. Using the shield on the antenna cable as the ground. 

Easy way to test the theory /concept is to get a long antenna cable, and connect it coiled up at the bench.


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## Greg Elmassian (Jan 3, 2008)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

Say what? No mention of PWM, talking about DC servos... 

Greg


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## Brandon (Jul 6, 2011)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

Posted By JPCaputo on 16 Dec 2011 12:17 AM 
For the frequency the Pwm frequency the cable can be extended around 10 ft or so. What you may have trouble with is the current needed to for the motor. 

One way I know can go long distances with little to no signal loss, use rf antenna cable for the long signal runs. Along with a pos voltage cable. Using the shield on the antenna cable as the ground. 

Easy way to test the theory /concept is to get a long antenna cable, and connect it coiled up at the bench. 
Thanks for the info on servo pwm distance. 10' is a fair bit, longer than I thought but shorter than I hoped (100' would have been nice...) I can see how voltage drop over a long distance would make it hard to provide current that far out, especially when dealing with pwm on the small motors since servo's do need a fair bit of current. 


I started to look for some pneumatic valves that were servo controlled (I need a way to control the switches from a computer and usb relay boards are quite expensive but you can get a usb 24 port servo controller for $50 which would be enough for all my switches and $2 a switch vs about $10 per switch for usb relay boards). No luck yet on a servo controlled valve but this gave me an interesting thought. 


Greg, can your switches by hand thrown as well or can they only be controlled by the solenoid valve and electronics? I couldn't see a manual throw on the solenoid you used. I'm wondering if you have to (or most people did because of cost or complexity) pick either solenoid or hand toggle. 

Then the thought came to me of having a servo throw a mechanical pneumatic toggle switch to be able to throw switches both ways. Basically I could solder a ring (maybe an EZ connector for model airplanes/servos) to the top of the toggle switch and use a servo/control rod to push/pull the switch. I could also easily disconnect the control rod and hand throw or disable a switch if I wanted or needed to -- the best of both worlds. The price per switch would be $2 (usb controller portion) $5 servo, then the cost of each pneumatic switch parts ~$23. So for about $30 per switch I could have computer controlled pneumatic switch. This would eliminate the need for a $24 solenoid and $10 usb relay to control the solenoid with a $9 toggle switch, $5 servo and $2 cost for the usb servo port. So $34 vs $16 and for less cost I also get manual control if needed. Add the $8 actuating cylinder, ~$1 per port for the manifold and you're only at $25 per switch plus the cost of any other bits and pieces. 


Thoughts?


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## High Ball John (Jan 26, 2009)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

I use solenoid values and have not had one failure in over five years in any part of the system. They are controller from my DCC system by using Littfinski SA-DEC-4 standalone decoders, the relays on the SA-DEC-4 are used to turn the power on and off to the solenoid valves. I also do computer control. 
  
http://www.ldt-infocenter.com/english/sadec02e.htm


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## Greg Elmassian (Jan 3, 2008)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

No manual throw on my switches, but it is easy to add pushbuttons to the DCC controller. If you needed a manual throw at the switch, it would not really be convenient to do it with air power, in my opinion. I control all my switches from any wireless throttle. 

In my case, all of the electronics is far away from the switch, only the 1/8" air line is out there in the elements, the switch activates with pressure, an internal return spring moves it in the opposite direction when pressure is released. 

My method is definitely not the lowest cost. It is, however, the most bulletproof, weatherproof, and reliable remote control system I have encountered, which was my goal. 

Regards, Greg


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## Cougar Rock Rail (Jan 2, 2008)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

You may also want to look at the Uhlenbrock digital servo which has a built in decoder. That to me would be the simplest assuming you wanted to use a servo--hook it your track power DCC and away you go. http://shop.conrad-uk.com/hobbies/m...igital-systems/uhlenbrock-digital/248046.html 

You would have to do a little work to waterproof it though. If you are building a new layout then maybe the air system would be viable, but I sure wouldn't want to have to retrofit that system into an existing layout. 

Keith


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## Mike Reilley (Jan 2, 2008)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

Clippard sells a complete line of pneumatic valves. Here's one of the simpler ones. Clippard EC-2-12 Electronic valve

Here's a link to all the 2 way electrically controlled valves. Clippard 2 way valves


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## High Ball John (Jan 26, 2009)

*RE: Are pneumatic switch still less hassle if you need DC Solenoid valves to control them?*

Weather proofing is not required with any of this pneumatic stuff, if the system is designed correctly. All of the electronics, valves etc can be kept inside with your control system. All that is needed outside is air hose and the actual activators. 

http://www.youtube.com/user/ytgeorgc


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