On Fri, 03 Jul 2009 12:39:45 -0500, Jon Elson
wrote:

Don Foreman wrote:

One difference between the approaches is that the cams operate the
mechanical switches gradually compared to switches and electric air
valves, so changing to electric might introduce some "hammer" when
they abruptly open and/or close. The difference may also affect
system timing, but once set up right it would tend to survive repairs
involving replacement of switches and/or valves.
No, these MicroSwitch pneumatic valves are
snap-action, just like an electrical MicroSwitch.
I have some of them in my pick and place
machine, and they definitely do not respond slowly.

Jon

Right. They may be noticably quicker than mechanical valves operated
by cams.