Post By atomarc
Question on wiring a air cylinder
I want to hard wire a air cylinder to go back and forth with a timed stop while it is fully extracted and it would still have tohave pressure forward until the timer times out. Is there a way of doing this?
There are small solid state recycling timers that are pretty inexpensive and could control the solenoid valve the directs the cylinder. McMaster Carr has these little 'ice cube' times along with a great explanation page telling how the various types work.
Automation Direct has some very low cost PLC's, they have one called the Click or something like that
that has free software and free tech support.
Depending on how precise your timing needs are, you could do this with, say, a Festo VZO time delay valve and simple pneumatic logic.
You can get it all done with air, and save needing to run power/solenoids/PLCs/etc. entirely.
Festo also sells straight up timers, some of which are accurate to 1/10 of a second.
Like DB said timing accuracy will dictate how compelex your device will need to be. I could rig up somthing rather simple with a couple limit switches, pneumatic vales and an off the shelf type timer.
I moonlight doing R & D work and machine repair. If your intersted pm me with some specs.
I built an automated feed mechanism that uses a pneumatic cyliner shuttling back and forth that needs to stay at one end of the stroke for several seconds. The rod has a small cam mounted on it that hits a pneumatic limit swith on either end. The output from the limit switch drives a piloted valve, which is what ultimately makes it go back and forth.
To create a time delay on one end the output from the limit switch goes through a meter in flow control to a small reservoir, then out to the pilot input on the valve. In use, it takes a few seconds to fill the reservoir before the vlave will see the pilot pressure and switch the direction of the piston. No electrical parts are required.