Selection of control or operating modes
Annex I of the Machinery Directive describes the essential health and safety requirements & article 1.2.5 refer to the selection of control or operating modes.
The control or operating mode selected must override all other control or operating modes, with the exception of the emergency stop.
If machinery has been designed and constructed to allow its use in several control or operating modes requiring different protective measures and/or work procedures, it must be fitted with a mode selector which can be locked in each position. Each position of the selector must be clearly identifiable and must correspond to a single operating or control mode.
The selector may be replaced by another selection method which restricts the use of certain functions of the machinery to certain categories of operator.
If, for certain operations, the machinery must be able to operate with a guard displaced or removed and/or a protective device disabled, the control or operating mode selector must simultaneously:
- disable all other control or operating modes,
- permit operation of hazardous functions only by control devices requiring sustained action,
- permit the operation of hazardous functions only in reduced risk conditions while preventing hazards from linked sequences,
- prevent any operation of hazardous functions by voluntary or involuntary action on the machine's sensors.
If these four conditions cannot be fulfilled simultaneously, the control or operating mode selector must activate other protective measures designed and constructed to ensure a safe intervention zone.
In addition, the operator must be able to control operation of the parts he is working on from the adjustment point.
The Edition 2.2 of the Guidelines will explain that in detail.