The 5 V DC power is needed by the CPU, the control of the interfaces, and the I/O modules. It is generated by a clocked 24 V DC/ 5V DC power supply module bearing the F 7130A identification. The subrack is equipped with two power supply modules. The power supply modules are paralleled. If one of them fails, the other supplies the PES.The 5 V DC output voltage of the power supply modules (for the CPU, I/O, and the interfaces) are monitored on the central unit checking undervoltage and failure.
