ABB Relion 670 series, Technical Reference Manual, Page: 1098 / 1232

19.2.4.2 Functionality
The NUM, Numeric processing module is a high performance, standard off-the-shelf
compact-PCI CPU module. It is 6U high and occupies one slot. Contact with the
backplane is via two compact PCI connectors and an euro connector.
The NUM has one PMC slot (32-bit IEEE P1386.1 compliant) and two PC-MIP slots
onto which mezzanine cards such as SLM or LDCM can be mounted.
To reduce bus loading of the compact PCI bus in the backplane the NUM has one
internal PCI bus for internal resources and the PMC/PC-MIP slots and external PCI
accesses through the backplane are buffered in a PCI/PCI bridge.
The application code and configuration data are stored in flash memory using a flash
file system.
The NUM is equipped with a real time clock. It uses a capacitor for power backup of
the real time clock.
No forced cooling is used on this standard module because of the low power dissipation.
Section 19
1MRK505222-UUS C
IED hardware
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Technical reference manual