... what are the requirements for mounting emergency stop buttons?

Safety Simplifier with emergency stop button and operating elements

The stopping of machines in an emergency situation is probably one of the most important requirements of the Machinery Directive 2006/4 2/EC. This gives rise to the requirement that every machine or plant must have at least one or more emergency stop command devices. It must be possible to stop an unexpectedly occurring, dangerous machine situation as quickly as possible by one of the operators.

» EN ISO 13850:2015 "Safety of machinery Emergency stop function design principles" considers the emergency stop command devices, as well as the basic requirements for an emergency stop function. «

Under point 3.9 of EN 13850, an operator station is defined as follows

Operator station with display

Operating station on enable switch

Operating station at a material lock

Operating station on safety switch

Point 4.3.2 of EN 13850 describes what must be observed when mounting an emergency stop button:

Basically at every operator station (unless a C standard or risk assessment comes to a different conclusion).
At all locations or positions defined by the risk assessment
At all positions where persons intervene in the system, such as during setup with an enabling switch. If there is no emergency stop button in the operator's direct working area, it must ideally be installed on the enabling switch.
At all positions where persons come into contact with the machine/system, for example during loading and unloading