Product Announcement from ABB Low Voltage Products & Systems
Safety Devices have a fixed amount of time it takes to react to a demand of the safety function which is compounded with the more controls you use, i.e. a Light Curtain, a Safety Relay, switching contactors, etc.
Due to the tolerance stack up of these devices, it may be possible to reach through the Light Curtain and reach the hazard before the machine has stopped.
By installing safety on the machine and not knowing the "true" stop time, you may be exposed to more danger than if you did not have any safety at all. Improperly installed safety devices give a false sense of security.