JVL MAC050 User Manual page 271

5.7 Emergency stop considerations
Paragraph 9.2.5.4.2 Emergency stop (DS/EN 60204-1)
Principles for the design of emergency stop equipment, including functional aspects, are
given in ISO 13850.
The emergency stop shall function either as a category 0 or as a category 1 stop (para-
graph 9.2.2 in DS/EN 60240-1). The choice of the stop category of the emergency stop
depends on the results of a risk assessment of the machine.
In addition to the requirements for stop functions (paragraph 9.2.5.3 in DS/EN 60204-1),
the emergency stop function has the following requirements:
- it shall override all other functions and operations in all modes.
- power to the machine actuators that can cause a hazardous situation(s) shall be either
removed immediately (category 0 stop) or shall be controlled in such a way to stop
the hazardous motion as quickly as possible (stop category 1) without creating other
hazards.
- reset shall not initiate a restart.
Considerations are also given regarding the safety and reliability of control circuits:
5.7.3 Paragraph 9.4 Control functions in the event of failure
Paragraph 9.4.1 General requirements (DS/EN 60204-1)
Where failures or disturbances in the electrical equipment can cause a hazardous
situation or damage to the machine or to the work in progress, appropriate measures
shall be taken to minimize the probability of the occurrence of such failure or
disturbances. The required measures and the extent to which they are implemented,
either individually or in combination, depend on the level of risk associated with the
respective application (paragraph 4.1in DS/EN 60204-1).
The electrical control circuits shall have an appropriate level of safety performance that
has been determined from the risk assessment at the machine. The requirements of IEC
62061 and/or ISO 13849-1:1999, ISO 13849-2:2003 shall apply.
Measures to reduce those risks include, but are not limited to:
- Protective devices on the machine (for example. interlocks guards, trip devices),
- Protective interlocking of the electrical circuit,
- use of proven circuit techniques and components (paragraph 9.4.2.1 in DS/EN
60204-1)
- provision of partial or complete redundancy (paragraph 9.4.2.2 in DS/EN 60204-1)
or diversity (paragraph 9.4.2.3 in DS/EN 60204-1),
- Provision for functional tests (paragraph 9.4.2.4 in DS/EN 60204-1).
As noted, reference is made to several other standards which describe how safety relat-
ed parts of the control system can be implemented.
In practice DS/EN 954-1 can be used, although this will be superseded by DS/EN ISO
13849-1 in 2009. The principles of both standards is the same: to first determine the
required level of safety and reliability of the control circuits and thereafter design the
safety related components of the control system to achieve the required level.
In DS/EN 954-1 the architecture of the safety related circuits is used exclusively as the
goal for the level of safety. The standard prescribes 5 categories: B, 1, 2, 3, and 4, where
B represents the lowest level and 4 the highest.
JVL Industri Elektronik A/S - User Manual - Integrated Servo Motors MAC050 - 800 267