BS EN 50155 pdf free download

BS EN 50155-2021 pdf free download.Railway applications一Rolling stock一Electronic equipment.
4 General requirements
4.1 Requirement for equipment characteristics
The requirements for equipment characteristics (e.g. functional, electrical, mechanical, appearance, interfaces) shall be defined by the user or derived from market needs for a generic equipment.
The supplier will generate a technical specification how to fulfil these requirements.
4.2 Classes of environmental, constructional and service conditions
The standard specifies a set of default performance classes of requirements; different classes may be requested at tender stage.
The summary of default requirements is given in Annex A.
4.3 Performance criteria
4.3.1 General
The normal performance level (i.e. the equipment is functioning as specified), expected from the equipment under test, shall be specified.
If agreed between the involved parties, the normal performance level of the equipment under test can be replaced by a defined deviation of the specified performance.
If the deviation of the normal performance of the equipment under test is not specified by the manufacturer/supplier, either of these may be derived from the product description and documentation and what the user may reasonably expect from the equipment if used as intended.
No damage to any connected equipment is allowed when the electronic equipment does not operate as intended during or after the test. Possible causes of failure are incorrect timing of output signals, overvoltage outside specifications, etc.
4.3.2 Performance criterion A
The equipment shall continue to operate as intended during and after the test and/or during and after an environmental disturbance.
No degradation of performance or loss of function is allowed.
Changes of actual operating state or stored data are not allowed.
Performance criterion A also satisfies performance criteria B and C.
4.3.3 Performance criterion B
The equipment shall continue to operate as intended after the test or after an environmental disturbance.
However, during the test or an environmental disturbance, degradation of performance is allowed.
Changes of actual operating state or stored data are not allowed.
Performance criterion B also satisfies performance criterion C.
4.3.4 Performance criterion C
During the test or during an environmental disturbance, temporary loss of function is allowed. The equipment:
— shall automatically restart. The normal performance shall be obtained within a maximum defined time. After this time the equipment shall retain the previous operating state and shall work as intended. The loss of significant stored data is not allowed;
NOTE Significant stored data are application dependent and stated in the equipment documentation.
or:
— shall be manually restarted or process-controlled restarted. In this case the restart process shall be clearly defined in the user manual and agreed between user and supplier at tender stage.
4.4 Environmental service conditions
4.4.1 Altitude
The altitude at which the equipment is normally to function should not exceed the values called for in EN 50125-1:2014, Table 1 “Classes of altitude range”. If the required altitude exceeds the one specified in EN 50125-1:2014, Table I class Al, compliance with the requirements shall be agreed between the involved parties.
Unless otherwise specified, the requirements of EN 50125-1:2014, Table I class Al apply.BS EN 50155 pdf download.