At City Tech (where I teach) we are in the process of unifying all our automation controls. Being a school with a mission of serving the industry, we try to adopt industry best practices as much as possible. Previously, I surveyed the industry to see the most popular I/O voltage.
Now, I'm looking at Emergency Stop (E-Stop) control for show equipment. If you work with this kind of gear, please take two minutes and fill out this survey before 10am NYC time Friday, December 7. Thanks!
I will post results here on controlgeek.net