Beckhoff EL1918 Operation Manual page 31

Operation
5.2.3.5 Notes on the arrangement of TwinSAFE components
The following notes illustrate favorable and unfavorable terminal arrangements from a thermal perspective.
Components with higher waste heat are identified with a red symbol , components with lower waste heat
are identified with a blue symbol .
EK11xx EtherCAT Coupler and EL9410 power supply terminal
The more terminals are attached after an EtherCAT Coupler or a power supply terminal, the higher the E-bus
current that their power supply units have to supply. With increasing current the waste heat from the power
supply units also increases.
EL69x0
The EL69x0 emits a relatively high amount of waste heat, since it has a high internal clock rate and high
logic performance.
EL2904, EL291x, EL291x-2200
The EL2904 emits a relatively high amount of waste heat due to the potentially high output current of the
connected actuators.
EL1904
The EL1904 also emits a relatively high amount of waste heat, despite the fact that the external load due to
clock outputs and safe inputs is relatively low.
Thermally unfavorable arrangement of the TwinSAFE terminals
The following arrangement is rather unfavorable, as terminals with relatively high waste heat are attached
directly to the EtherCAT Coupler or the power supply terminal with high E-bus load. The additional external
heating of the TwinSAFE terminals by the adjacent power supply units increases the internal terminal
temperature, which can lead to the maximum permissible temperature being exceeded. This leads to the
diagnosis message "Overtemperature".
EL1918 and EL1918-2200 Version: 2.0.0 31