GE P742

P74
x/EN FD/Na7
Firmware Design
(FD) 9
-
8
MiCOM P74
1, P742, P743
FD
FIGURE 4: RELAY MODULES AND INFORMATION FLOW
1.2.2 System services software
The system services software provides the low-level control of the relay hardware. For
example, the system services software controls the boot of the relay’s software from the
non-volatile flash EPROM memory at power-on, and provides driver software for the user
interface via the LCD and keypad, and via the serial communication ports. The system
services software provides an interface layer between the control of the relay’s hardware and
the rest of the relay software.