There is no way to control the position of a pneumatic cylinder without mechanical stops. Once air enters the cylinder, the piston will move based on the air pressure and the force it is trying to move. If it can overcome the force it is trying to move, it will move until it comes to the end of it’s travel (a mechanical stop inside the cylinder). You can control the speed at which the cylinder is moved by using flow control valves at the ports of the cylinder. There is a tradeoff in the time it takes to travel.
You can use a double solenoid valve with a spring return center off position to stop a piston in mid stroke. You can get vavles from SMC that look nearly identical to the double solenoid valves we recieved in the kit but are about 1 cm longer that will accomplish what you want.
You want an smc SY3340-6H, which is a three position, close center valve. The one in the KOP is a two position, so it won’t stop in the middle. Warning: when a cylinder stops halfway, it will be “spongy” because its air holding it. If its a light load, it might be OK. Be forewarned, when it drops, it will drop quickly for a small amount until the air is compressed on the drop side.
You can send the vent from the first valve to another valve. The first controls direction and the second is stop/go. There are some nuances to this method but and old team I was on used it with moderate success.
This is the flow control fitting that comes with the kit. You use it instead of the standard fitting. The little white knob controls how fast the air fills the cylinder giving you control of the speed but it will still deliver the full 60psi.