http://www.sea.siemens.com/instrbu/docs/pdf/77%20&%20771.pdf
I understand the pros and cons of using electronics to control pneumatics from the perspective of a control technican and that of an operating engineer.
If all else fails, the watch engineer can pull off the control devices and...
I don't have a quick and easy answer, but I did find some interesting links.
I am reading them myself.
http://www.saftronics.com/pdf_fils/CaseStudy/CS_VFD_001.pdf...