I have a prototype machine with mechanical moving parts (all contained inside a transparent interlocked enclosure) to review. Single-phase AC power enters at the rear via a fused IEC 60320 C14 inlet, through a rotary isolator switch (adjacent to the inlet at the rear) to a front-mounted emergency stop switch and then on to the rest of the unit.
The main unit is controlled via an LCD display with a rotary turn and click encoder for navigating menus. Selecting a task and starting / stopping it is achieved via this interface - effectively implementing a software Start / Stop switch. All stops are uncontrolled - i.e. a shutdown signal is sent to the motor drivers causing an immediate loss of power to all moving parts (they have minimal inertia).
In many machines with simpler functionality (pillar drill, band saw) I see this same topology but with the addition of a series contactor controlled by a pair of mechanical Start and Stop switches. Obviously, in this case there is no need for a complex LCD + encoder control system, so the start and stop switches are both necessary and sufficient. But in the case of the system I have described , does the LCD control described provide compliant control of the system, or is an additional pair of mechanical Start / Stop switches required for compliance with EN60204?