EN 50155-2017 pdf download.Railway applications – Rolling stock – Electronic equipment.
4.2.4 Performance criterion C
During the testlevent temporary loss of function is allowed. The equipment could:
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 data is not allowed; or
manually restart or process controlled restart. In this case this shall be agreed between user and supplier and/or clearly defined in the user manual. In this case the user manual shall be available to the user at the tender stage.
NOTE Significant stored data are application dependent and stated into the Performance specifications.
4.3 Environmental service conditions
4.3.1 Altitude
The altitude at which the equipment is normally to function does not exceed the values called for in
EN 50125-1:2014, Table I “Classes of altitude range”. In case of required attitude above the
EN 50125-1:2014, Table 1 class Al, compliance with the requirements shall be agreed between the
involved parties.
Unless otherwise specified, the requirements of EN 50125-1:2014, Table 1 class Al apply.
4.3.2 Operating temperature
Electronic equipment shall be designed and manufactured to meet the full performance specification requirement for the selected temperature classes as stated in Table 1.
The supplier of the electronic equipment shall specify its power dissipation and the thermal integration constraints (e.g. natural convection cooling, forced air cooling, cooled plate, mounting position, free space inside integration volume, preheating, air outlet) to respect a correct integration of this electronic equipment into their operating environment.
The user of the electronic equipment shall respect the thermal integration constraints specified by the supplier and shall design the integration environment in order to ensure an operational temperature compliant with the operational temperature class of the integrated electronic equipment.
The requirements for active or assisted cooling system shall be described according to Subclause 12.5 Equipment integration/installation documentation
‘Electronic equipment” and integration environment” are generic designations applicable to several levels; some examples are listed below:
an “Enclosed” or “Open frame” complex component integrated on a PCB:
Class 0T5 and 0T6 cannot be used as a general specification for temperature in vehicle requirement (e.g. can be used for Semiconductor Drive Unit (SDU), combustion engine control unit).
Temperature classes OT1 and 0T2 should be used for passenger compartments and driver’s cab with a reference permanent temperature of 25 °C for which the effects on the material ageing are equivalent to those of the climatic temperature during lifetime. 0T3 and 0T4 should be used for equipment in technical cabinet with a reference permanent temperature of 45 C for which the effects on the material ageing are equivalent to those of the climatic temperature during lifetime.
Unless otherwise specified, the requirements of category 0T3 apply.
4.3.3 Switch-on extended operating temperature
The design shall take into account temperature rises within cubicles to ensure that the components do not exceed their specified temperature ratings. For example, it is expected, that the air temperature surrounding the individual printed boards rises about 15 °C (this temperature rise depends significantly on the power dissipation of the board itself and on the power dissipation of other boards in the vicinity of it, on the natural or forced air flow, etc.). This shall be taken into account for the design of the PBA. particularly when individual PBA’s are intended to be horizontally or vertically juxtaposed or when sub-racks containing the PBAS are superposed.
The supplier should take into account the requirements resulting from the specific an board installation (see Annex C).
In some special cases (e.g. cubicle, effect of sun, assisting cooling system shutdown) an extra operational check at the equipment switched on at short-term thermal conditions is carried out according to the classes ST1 or ST2 of Table 2.EN 50155-2017 pdf download.