Rodless air cylinder being semi automated

by GGarner
(San Diego CA)

I am setting up a semi automated spray booth at my company (small company so I am doing it myslef)

I purchased a 6' long rodless air cylinder which will support the spray head/atomizer.

The question is I am having a hard time figuring out what type of switches to use and how to do the wiring. The air cylinder has a magnet in it so a reed switch seems to be the way to go. We want the trolley to travel to the ends of the rail so i imagine putting the reed switches where they trigger when the trolley gets to the end of its run. Then I want it to reverse direction and do the same thing at the other end.

I am new to pneumatics so I dont know what sort of a solenoid I should use. I am pretty sure that I need a 4 way 2 position solenoid but am unsure if i should use one with a single solenoid and spring or dual solenoid.

The more I think about it the more i think the dual solenoid would be the way to go.

Is my following logic correct given the following configuration:
Dual solenoid is plumbed as follows
In: from air regulator
Out: nothing... exhausts into room
A: plumbed for right to left motion
B: plumbed for left to right motion

The solenoid which activates left to right motion is wired to the reed switch 1 on the left side of cylinder


The solenoid which activates right to left motion is wired to reed switch 2 on the right side of the cylinder

Say the trolley starts out with path A (R to L) active it passes by the reed switch 1 firing the solenoid to activate path B. Then travels L to R activates reed switch 2 and the whole thing repeats???

In order to reduce any shock hazzard I am running 24V DC solenoid/transformer etc.

I am also curious about how to do the electrical wiring.
- from 24v transformer to reed switch 1 then to solenoid activating path A
- from 24v transformer to reed switch 2 then to solenoid activating path B
+ from all solenoids to + on transformer

___________________-
Bill says...

First off, for a spray application, either you want to find explosion proof or intrinsically safe solenoids to avert an explosion.

Your overall logic works, yet in your application, I would opt for an all pneumatic logic sequence to avoid the use of electricity altogether.

Either way you wish to go, setting up air circuits is something I do, but not for free. If you wish a quotation from me to prepare a circuit and drawings for you, please send in another ASK question with the words "need quote for logic" as the subject, so I can get to it more quickly.

Cheers,

Bill