An engineer at a packaging company asked:

NFPA 79, 2007, Paragraph 9.2.7.5 states:

Use of more than one Operator Control Station; Where a machine has more than one operator control station measures shall be taken to ensure that only one control station shall be enabled at a given time.

If you're familiar with this code, what does it really mean and how is it best applied? I have a machine line with 5 stations and I need to control the machine at any of the 5 stations. Do I have to lockout all stations but one and how do I switch stations?

SafetyMan Says:

It is not necessary to lock out the stations. One recommendation would be to use a supervisory control such as a key switch that enables the station when it needs to be in service. The key would be in your possession when you are not at the particular station.

A similar solution would be a password protected device, such as an HMI,  allowing use of the system with perhaps a time out back to locked if the station is not used.